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Heritability of pain catastrophizing and associations with experimental pain outcomes: a twin study.
Trost, Zina; Strachan, Eric; Sullivan, Michael; Vervoort, Tine; Avery, Ally R; Afari, Niloofar
This study used a twin paradigm to examine genetic and environmental contributions to pain catastrophizing and the observed association between pain catastrophizing and cold-pressor task (CPT) outcomes. Male and female monozygotic (n = 206) and dizygotic twins (n = 194) from the University of Washington Twin Registry completed a measure of pain catastrophizing and performed a CPT challenge. As expected, pain catastrophizing emerged as a significant predictor of several CPT outcomes, including cold-pressor Immersion Tolerance, Pain Tolerance, and Delayed Pain Rating. The heritability estimate for pain catastrophizing was found to be 37% with the remaining 63% of variance attributable to unique environmental influence. Additionally, the observed associations between pain catastrophizing and CPT outcomes were not found attributable to shared genetics or environmental exposure, which suggests a direct relationship between catastrophizing and experimental pain outcomes. This study is the first to examine the heritability of pain catastrophizing and potential processes by which pain catastrophizing is related to experimental pain response.
Decreased pain sensitivity among people with schizophrenia: a meta-analysis of experimental pain induction studies.
Stubbs, Brendon; Thompson, Trevor; Acaster, Sarah; Vancampfort, Davy; Gaughran, Fiona; Correll, Christoph U
Patients with schizophrenia report reduced pain sensitivity in clinical studies, but experimental studies are required to establish pain sensitivity as a potential endophenotype. We conducted a systematic review of electronic databases from database inception until April 15, 2015, including experimental studies investigating pain among patients with schizophrenia spectrum disorder vs healthy controls. A random-effect meta-analysis yielding Hedges' g ±95% confidence intervals (CIs) as the effect size (ES) measure was conducted. Primary outcome was a pooled composite of pain threshold and pain tolerance; secondary outcomes included these parameters individually, plus sensory threshold, physiological pain response, and pain intensity or unpleasantness. Across 17 studies, patients with schizophrenia spectrum disorder (n = 387; age, 30.7 ± 6.9 years; females, 31.9%; illness duration, 7.0 ± 5.7 years) were compared with controls (n = 483; age, 29.5 ± 7.4 years; females, 31.0%). Patients had elevated pain threshold/pain tolerance vs controls (ES = 0.583; 95% CI, 0.212-0.954; P = 0.002; studies = 15). Results were similar in antipsychotic-free individuals (ES = 0.599; 95% CI, 0.291-0.907; P < 0.0001; studies = 8), with trend-level significance in antipsychotic-treated individuals (ES = 0.566; 95% CI, -0.007 to 1.125; P = 0.047; studies = 9). Likewise, patients with schizophrenia had increased pain tolerance (ES = 0.566; 95% CI, 0.235-0.897; P = 0.0001; studies = 6), sensory threshold (ES = 1.16; 95% CI, 0.505-1.727; P < 0.0001; studies = 5), and pain threshold (ES = 0.696; 95% CI, 0.407-0.986; P < 0.001; studies = 9), as well as reduced physiological response to noxious stimuli (ES = 0.456; 95% CI, 0.131-0.783; P = 0.006) and pain intensity/unpleasantness ratings (ES = 0.547; 95% CI, 0.146-0.949; P = 0.008). Findings were similarly significant in antipsychotic-free patients with schizophrenia (analysable parameters = 4) and antipsychotic-treated individuals (analysable
The effect of paracetamol and tropisetron on pain: experimental studies and a review of published data.
Tiippana, Elina; Hamunen, Katri; Kontinen, Vesa; Kalso, Eija
Experimental studies suggest that paracetamol-induced analgesia is mediated via central serotonergic pathways and attenuated by 5-HT3-antagonists. However, clinical studies do not support this, and 5-HT3-antagonists are expected to reduce pain by blocking the descending pronociceptive pathway. The current project tested whether tropisetron attenuates analgesia by paracetamol. Two randomized, double-blind, crossover studies with 18 healthy male volunteers in each were performed. Pain stimuli were cold water immersion (cold pressor test), contact heat pain (study 1) and electrical stimulation (study 2). In both studies, tropisetron 5 mg i.v. or saline was administered, followed by paracetamol 2 g i.v. 30 min. later. Individual changes in heat and cold pain intensity, cold pain tolerance and unpleasantness were recorded. The same thresholds were also expressed as scores (% of the individual score at baseline). Additionally, previously published findings on the effects of paracetamol and its interaction with 5HT3-antagonists in human experimental pain models were reviewed. After calculation of the sensory and pain scores (%), tropisetron seemed to amplify the analgesic action of paracetamol. Paracetamol 2 g i.v. did not show any statistically significant analgesia in thermal tests (study 1), or differences in sensory, pain detection or moderate pain thresholds of the electrical stimulus (study 2). As paracetamol did not have a measurable analgesic effect in these tests, no conclusions can be drawn about the interaction between paracetamol and tropisetron. However, tropisetron may have an analgesic effect of its own. Clinicians should not avoid using these drugs together, unless larger clinical studies indicate otherwise.
No effect of a single session of transcranial direct current stimulation on experimentally induced pain in patients with chronic low back pain--an exploratory study.
Luedtke, Kerstin; May, Arne; Jürgens, Tim P
Transcranial direct current stimulation (tDCS) has been shown to modulate cortical excitability. A small number of studies suggested that tDCS modulates the response to experimental pain paradigms. No trials have been conducted to evaluate the response of patients already suffering from pain, to an additional experimental pain before and after tDCS. The present study investigated the effect of a single session of anodal, cathodal and sham stimulation (15 mins/1 mA) over the primary motor cortex on the perceived intensity of repeated noxious thermal and electrical stimuli and on elements of quantitative sensory testing (thermal pain and perception thresholds) applied to the right hand in 15 patients with chronic low back pain. The study was conducted in a double-blind sham-controlled and cross-over design. No significant alterations of pain ratings were found. Modalities of quantitative sensory testing remained equally unchanged. It is therefore hypothesized that a single 15 mins session of tDCS at 1 mA may not be sufficient to alter the perception of experimental pain and in patients with chronic pain. Further studies applying repetitive tDCS to patients with chronic pain are required to fully answer the question whether experimental pain perception may be influenced by tDCS over the motor cortex.
No Effect of a Single Session of Transcranial Direct Current Stimulation on Experimentally Induced Pain in Patients with Chronic Low Back Pain – An Exploratory Study
Luedtke, Kerstin; May, Arne; Jürgens, Tim P.
Transcranial direct current stimulation (tDCS) has been shown to modulate cortical excitability. A small number of studies suggested that tDCS modulates the response to experimental pain paradigms. No trials have been conducted to evaluate the response of patients already suffering from pain, to an additional experimental pain before and after tDCS. The present study investigated the effect of a single session of anodal, cathodal and sham stimulation (15 mins/1 mA) over the primary motor cortex on the perceived intensity of repeated noxious thermal and electrical stimuli and on elements of quantitative sensory testing (thermal pain and perception thresholds) applied to the right hand in 15 patients with chronic low back pain. The study was conducted in a double-blind sham-controlled and cross-over design. No significant alterations of pain ratings were found. Modalities of quantitative sensory testing remained equally unchanged. It is therefore hypothesized that a single 15 mins session of tDCS at 1 mA may not be sufficient to alter the perception of experimental pain and in patients with chronic pain. Further studies applying repetitive tDCS to patients with chronic pain are required to fully answer the question whether experimental pain perception may be influenced by tDCS over the motor cortex. PMID:23189136
The role of neuroplasticity in experimental neck pain: a study of potential mechanisms impeding clinical outcomes of training.
Rittig-Rasmussen, Bjarne; Kasch, Helge; Fuglsang-Frederiksen, Anders; Svensson, Peter; Jensen, Troels Staehelin
Training is a mainstay in the clinical management of neck pain, yet, effects of various training protocols are only small to moderate and improvements are required. Previous investigations of the nervous system indicate a correlation between neuroplastic adaptation to training and functional recovery. The interaction between neck pain and training thus needs further exploration. This was a randomized experimental study of the effects of experimental neck pain and training on corticomotor excitability. Healthy volunteers were randomized to training and experimental neck pain, training and no pain, and pain and no training. Primary endpoints were corticomotor excitability assessed by transcranial magnetic stimulation and electromyography measured as changes in amplitudes and latencies of motor evoked potentials (MEPs), recorded at baseline and after 30 min, 1 h, and 1 week. Additionally, correlations between changes in MEPs and motor learning, effects of pain and concomitant neck training on pain, muscle strength, and fatigue were investigated. Data were analyzed by repeated measurement ANOVA, paired t tests, Grubbs' outlier test and correlation coefficients. Results indicated that neck pain and training significantly enhanced the inhibition of the amplitudes of the MEPs for 1 week. The results indicate that moderate neck pain and training induce long-lasting inhibition of the corticomotor pathways. This inhibition may limit the outcome of neck training in painful conditions in contrast to pain-free training conditions.
Experimental tooth clenching. A model for studying mechanisms of muscle pain.
Dawson, Andreas
The overall goal of this thesis was to broaden knowledge of pain mechanisms in myofascial temporomandibular disorders (M-TMD). The specific aims were to: Develop a quality assessment tool for experimental bruxism studies (study I). Investigate proprioceptive allodynia after experimental tooth clenching exercises (study II). Evaluate the release of serotonin (5-HT), glutamate, pyruvate, and lactate in healthy subjects (study III) and in patients with M-TMD (study IV), after experimental tooth clenching exercises. In (I), tool development comprised 5 steps: (i) preliminary decisions, (ii) item generation, (iii) face-validity assessment, (iv) reliability and discriminative validity testing, and (v) instrument refinement. After preliminary decisions and a literature review, a list of 52 items to be considered for inclusion in the tool was generated. Eleven experts were invited to participate on the Delphi panel, of which 10 agreed. After four Delphi rounds, 8 items remained and were included in the Quality Assessment Tool for Experimental Bruxism Studies (Qu-ATEBS). Inter-observer reliability was acceptable (k = 0.77), and discriminative validity high (phi coefficient 0.79; P < 0.01). During refinement, 1 item was removed; the final tool comprised 7 items. In (II), 16 healthy females participated in three 60-min sessions, each with 24- and 48-h follow-ups. Participants were randomly assigned to a repetitive experimental tooth clenching task with a clenching level of 10%, 20%, or 40% of maximal voluntary clenching force (MVCF). Pain intensity, fatigue, perceived intensity of vibration (PIV), perceived discomfort (PD), and pressure pain threshold (PPT) were measured throughout. A significant increase in pain intensity and fatigue but not in PD was observed over time. A significant increase in PIV was only observed at 40 min, and PPT decreased significantly over time at 50 and 60 min compared to baseline. In (III), 30 healthy subjects (16 females, and 14 males
Pain in experimental autoimmune encephalitis: a comparative study between different mouse models
Background Pain can be one of the most severe symptoms associated with multiple sclerosis (MS) and develops with varying levels and time courses. MS-related pain is difficult to treat, since very little is known about the mechanisms underlying its development. Animal models of experimental autoimmune encephalomyelitis (EAE) mimic many aspects of MS and are well-suited to study underlying pathophysiological mechanisms. Yet, to date very little is known about the sensory abnormalities in different EAE models. We therefore aimed to thoroughly characterize pain behavior of the hindpaw in SJL and C57BL/6 mice immunized with PLP139-151 peptide or MOG35-55 peptide respectively. Moreover, we studied the activity of pain-related molecules and plasticity-related genes in the spinal cord and investigated functional changes in the peripheral nerves using electrophysiology. Methods We analyzed thermal and mechanical sensitivity of the hindpaw in both EAE models during the whole disease course. Qualitative and quantitative immunohistochemical analysis of pain-related molecules and plasticity-related genes was performed on spinal cord sections at different timepoints during the disease course. Moreover, we investigated functional changes in the peripheral nerves using electrophysiology. Results Mice in both EAE models developed thermal hyperalgesia during the chronic phase of the disease. However, whereas SJL mice developed marked mechanical allodynia over the chronic phase of the disease, C57BL/6 mice developed only minor mechanical allodynia over the onset and peak phase of the disease. Interestingly, the magnitude of glial changes in the spinal cord was stronger in SJL mice than in C57BL/6 mice and their time course matched the temporal profile of mechanical hypersensitivity. Conclusions Diverse EAE models bearing genetic, clinical and histopathological heterogeneity, show different profiles of sensory and pathological changes and thereby enable studying the mechanistic basis
Vicarious pain while observing another in pain: an experimental approach
Vandenbroucke, S.; Crombez, G.; Van Ryckeghem, D. M. L.; Brass, M.; Van Damme, S.; Goubert, L.
Objective: This study aimed at developing an experimental paradigm to assess vicarious pain experiences. We further explored the putative moderating role of observer's characteristics such as hypervigilance for pain and dispositional empathy. Methods: Two experiments are reported using a similar procedure. Undergraduate students were selected based upon whether they reported vicarious pain in daily life, and categorized into a pain responder group or a comparison group. Participants were presented a series of videos showing hands being pricked whilst receiving occasionally pricking (electrocutaneous) stimuli themselves. In congruent trials, pricking and visual stimuli were applied to the same spatial location. In incongruent trials, pricking and visual stimuli were in the opposite spatial location. Participants were required to report on which location they felt a pricking sensation. Of primary interest was the effect of viewing another in pain upon vicarious pain errors, i.e., the number of trials in which an illusionary sensation was reported. Furthermore, we explored the effect of individual differences in hypervigilance to pain, dispositional empathy and the rubber hand illusion (RHI) upon vicarious pain errors. Results: Results of both experiments indicated that the number of vicarious pain errors was overall low. In line with expectations, the number of vicarious pain errors was higher in the pain responder group than in the comparison group. Self-reported hypervigilance for pain lowered the probability of reporting vicarious pain errors in the pain responder group, but dispositional empathy and the RHI did not. Conclusion: Our paradigm allows measuring vicarious pain experiences in students. However, the prevalence of vicarious experiences of pain is low, and only a small percentage of participants display the phenomenon. It remains however unknown which variables affect its occurrence. PMID:23781187
Can personality traits and gender predict the response to morphine? An experimental cold pain study.
Pud, Dorit; Yarnitsky, David; Sprecher, Elliot; Rogowski, Zeev; Adler, Rivka; Eisenberg, Elon
The aim of the present study was to examine the possible role of personality traits, in accordance with Cloninger's theory, and gender, in the variability of responsiveness to opioids. Specifically, it was intended to test whether or not the three personality dimensions - harm avoidance (HA), reward dependence (RD) and novelty seeking (NS) - as suggested by Cloninger, can predict inter-personal differences in responsiveness to morphine after exposure to experimental cold pain. Thirty-four healthy volunteers (15 females, 19 males) were given the cold pressor test (CPT). Pain threshold, tolerance, and magnitude (VAS) were measured before and after (six measures, 30 min apart) the administration of either 0.5 mg/kg oral morphine sulphate (n=21) or 0.33 mg/kg oral active placebo (diphenhydramine) (n=13) in a randomized, double blind design. Assessment of the three personality traits, according to Cloninger's Tridimensional Personality Questionnaire, was performed before the CPT. A high HA score (but not RD, NS, or baseline values of the three pain parameters) predicted a significantly larger pain relief following the administration of morphine sulphate (but not of the placebo). Women exhibited a larger response in response to both treatments, as indicated by a significantly increased threshold and tolerance following morphine sulphate as well as significantly increased tolerance and decreased magnitude following placebo administration. The present study confirms the existence of individual differences in response to analgesic treatment. It suggests that high HA personality trait is associated with better responsiveness to morphine treatment, and that females respond better than men to both morphine and placebo.
Neuronal and immunological basis of action of antidepressants in chronic pain - clinical and experimental studies.
Mika, Joanna; Zychowska, Magdalena; Makuch, Wioletta; Rojewska, Ewelina; Przewlocka, Barbara
The current knowledge of the pharmacological actions of the tricyclic antidepressants (TCAs) has slowly evolved through their over 40-year history. Chronic pain represents one of the most important public health problems, and antidepressants are an essential part of the therapeutic strategy in addition to classical analgesics. This article reviews the available evidence on the efficacy and safety of antidepressants in chronic pain conditions; namely, headaches, low back pain, fibromyalgia, cancer pain and especially neuropathic pain. TCAs are traditionally the main type of depression medication used to treat chronic pain. Recently, new antidepressants were introduced into clinical use, with a significant reduction in side effects and equivalent efficacy on mood disorders. These new drugs that are effective for chronic pain belong to the tetracyclic antidepressants (TeCAs) group (amoxapine, maprotiline), the serotonin and noradrenaline reuptake inhibitors (SNRIs) group (duloxetine, venlafaxine, milnacipran) and the atypical antidepressants group (bupropion, trazodone, mirtazapine, nefazodone). In this review, we present the available publications on TCAs (amitriptyline, doxepin, imipramine, desipramine, nortriptyline), TeCAs (amoxapine, maprotiline), selective serotonin reuptake inhibitors (SSRIs) (citalopram, fluoxetine, paroxetine), SNRIs (duloxetine, venlafaxine, milnacipran) and atypical antidepressants (bupropion) for the treatment of neuropathic pain. We also review analgesics acting as both opioid receptor agonists and also acting as aminergic reuptake inhibitors. Existing data are insufficient to conclude which of these new classes of antidepressants has the best clinical profile and will be the most effective in the treatment of neuropathic pain; in addition, a lower incidence of side effects should be considered. Increased experimental and translational research is a key for further improvement of the treatment of chronic pain with antidepressants. However
Experimental manipulations of pain catastrophizing influence pain levels in patients with chronic pain and healthy volunteers.
Kjøgx, Heidi; Kasch, Helge; Zachariae, Robert; Svensson, Peter; Jensen, Troels S; Vase, Lene
Pain catastrophizing (PC) has been related to pain levels in both patients experiencing acute or chronic pain and in healthy volunteers exposed to experimental pain. Still, it is unclear whether high levels of pain catastrophizing lead to high levels of pain or vice versa. We therefore tested whether levels of pain catastrophizing could be increased and decreased in the same participant through hypnotic suggestions and whether the altered level of situation-specific pain catastrophizing was related to increased and decreased pain levels, respectively. Using the spontaneous pain of 22 patients with chronic tension-type headache and experimentally induced pain in 22 healthy volunteers, participants were tested in 3 randomized sessions where they received 3 types of hypnotic suggestions: Negative (based on the 13 items in the Pain Catastrophizing Scale), Positive (coping-oriented reversion of the Pain Catastrophizing Scale), and Neutral (neutral sentence) hypnotic suggestions. The hypnotic suggestions significantly increased and decreased situation-specific PC in both patients and healthy volunteers (P < 0.001). Also, the levels of pain intensity and pain unpleasantness were significantly altered in both patients and healthy volunteers (P < 0.001). Furthermore, regression analyses showed that changes in pain catastrophizing predicted changes in pain in patients (R = 0.204-0.304; P < 0.045) and in healthy volunteers (R = 0.328-0.252; P < 0.018). This is the first study to successfully manipulate PC in positive and negative directions in both patients with chronic pain and healthy volunteers and to show that these manipulations significantly influence pain levels. These findings may have important theoretical and clinical implications.
Effects of perceived and exerted pain control on neural activity during pain relief in experimental heat hyperalgesia: a fMRI study.
Mohr, C; Leyendecker, S; Petersen, D; Helmchen, C
Perceived control over pain can attenuate pain perception by mechanisms of endogenous pain control and emotional reappraisal irrespective of whether this control is exerted or only perceived. Self-initiated termination of pain elicits different expectations of subsequent pain relief as compared to perceived pain control. It is unknown whether and how this perceived vs. exerted control on pain differs and affects subsequent pain relief. Using fMRI, we studied two factors of pain control on pain relief: the (i) sense of control (perceived control but no execution) and (ii) the execution of control (exerted control). To account for the impact of factual execution of pain control on pain relief we applied bearable short and hardly bearable long contact-heat stimuli which were applied either controllable or not. Using controllability as factor, there was dissociable neural activity during pain relief: following the perceived control condition neural activity was found in the orbitofrontal and mediofrontal cortex and, following the exerted control condition, in the anterolateral and dorsolateral prefrontal cortex and posterior parietal cortex. We conclude that (i) pain controllability has an impact on pain relief and (ii) the prefrontal cortex shows dissociable neural activity during pain relief following exerted vs. perceived pain control. This might reflect the higher grade of uncertainty during pain relief following perceived pain control mediated by the orbitofrontal and medial prefrontal cortex and processes of working memory and updating expectations during pain relief following exerted control mediated by the lateral prefrontal cortex.
Reduced habituation to experimental pain in migraine patients: a CO(2) laser evoked potential study.
Valeriani, M; de Tommaso, M; Restuccia, D; Le Pera, D; Guido, M; Iannetti, G D; Libro, G; Truini, A; Di Trapani, G; Puca, F; Tonali, P; Cruccu, G
The habituation to sensory stimuli of different modalities is reduced in migraine patients. However, the habituation to pain has never been evaluated. Our aim was to assess the nociceptive pathway function and the habituation to experimental pain in patients with migraine. Scalp potentials were evoked by CO(2) laser stimulation (laser evoked potentials, LEPs) of the hand and facial skin in 24 patients with migraine without aura (MO), 19 patients with chronic tension-type headache (CTTH), and 28 control subjects (CS). The habituation was studied by measuring the changes of LEP amplitudes across three consecutive repetitions of 30 trials each (the repetitions lasted 5 min and were separated by 5-min intervals). The slope of the regression line between LEP amplitude and number of repetitions was taken as an index of habituation. The LEPs consisted of middle-latency, low-amplitude responses (N1, contralateral temporal region, and P1, frontal region) followed by a late, high-amplitude, negative-positive complex (N2/P2, vertex). The latency and amplitude of these responses were similar in both patients and controls. While CS and CTTH patients showed a significant habituation of the N2/P2 response, in MO patients this LEP component did not develop any habituation at all after face stimulation and showed a significantly lower habituation than in CS after hand stimulation. The habituation index of the vertex N2/P2 complex exceeded the normal limits in 13 out of the 24 MO patients and in none of the 19 CTTH patients (P<0.0001; Fisher's exact test). Moreover, while the N1-P1 amplitude showed a significant habituation in CS after hand stimulation, it did not change across repetitions in MO patients. In conclusion, no functional impairment of the nociceptive pathways, including the trigeminal pathways, was found in either MO or CTTH patients. But patients with migraine had a reduced habituation, which probably reflects an abnormal excitability of the cortical areas involved in
The effect of Reiki on pain and anxiety in women with abdominal hysterectomies: a quasi-experimental pilot study.
Vitale, Anne T; O'Connor, Priscilla C
The purpose of this pilot study was to compare reports of pain and levels of state anxiety in 2 groups of women after abdominal hysterectomy. A quasi-experimental design was used in which the experimental group (n = 10) received traditional nursing care plus three 30-minute sessions of Reiki, while the control group (n = 12) received traditional nursing care. The results indicated that the experimental group reported less pain and requested fewer analgesics than the control group. Also, the experimental group reported less state anxiety than the control group on discharge at 72 hours postoperation. The authors recommend replication of this study with a similar population, such as women who require nonemergency cesarian section deliveries.
Brain Network Response to Acupuncture Stimuli in Experimental Acute Low Back Pain: An fMRI Study.
Shi, Yu; Liu, Ziping; Zhang, Shanshan; Li, Qiang; Guo, Shigui; Yang, Jiangming; Wu, Wen
Most neuroimaging studies have demonstrated that acupuncture can significantly modulate brain activation patterns in healthy subjects, while only a few studies have examined clinical pain. In the current study, we combined an experimental acute low back pain (ALBP) model and functional magnetic resonance imaging (fMRI) to explore the neural mechanisms of acupuncture analgesia. All ALBP subjects first underwent two resting state fMRI scans at baseline and during a painful episode and then underwent two additional fMRI scans, once during acupuncture stimulation (ACUP) and once during tactile stimulation (SHAM) pseudorandomly, at the BL40 acupoint. Our results showed that, compared with the baseline, the pain state had higher regional homogeneity (ReHo) values in the pain matrix, limbic system, and default mode network (DMN) and lower ReHo values in frontal gyrus and temporal gyrus; compared with the OFF status, ACUP yielded broad deactivation in subjects, including nearly all of the limbic system, pain status, and DMN, and also evoked numerous activations in the attentional and somatosensory systems; compared with SHAM, we found that ACUP induced more deactivations and fewer activations in the subjects. Multiple brain networks play crucial roles in acupuncture analgesia, suggesting that ACUP exceeds a somatosensory-guided mind-body therapy for ALBP.
The effect of experimental low back pain on lumbar muscle activity in people with a history of clinical low back pain: a muscle functional MRI study.
Danneels, Lieven; Cagnie, Barbara; D'hooge, Roseline; De Deene, Yves; Crombez, Geert; Vanderstraeten, Guy; Parlevliet, Thierry; Van Oosterwijck, Jessica
In people with a history of low back pain (LBP), structural and functional alterations have been observed at several peripheral and central levels of the sensorimotor pathway. These existing alterations might interact with the way the sensorimotor system responds to pain. We examined this assumption by evaluating the lumbar motor responses to experimental nociceptive input of 15 participants during remission of unilateral recurrent LBP. Quantitative T2 images (muscle functional MRI) were taken bilaterally of multifidus, erector spinae, and psoas at several segmental levels (L3 upper and L4 upper and lower endplate) and during several conditions: 1) at rest, 2) upon trunk-extension exercise without pain, and 3) upon trunk-extension exercise with experimental induced pain at the clinical pain-side (1.5-ml intramuscular hypertonic saline injections in erector spinae). Following experimental pain induction, muscle activity levels similarly reduced for all three muscles, on both painful and nonpainful sides, and at multiple segmental levels (P = 0.038). Pain intensity and localization from experimental LBP were similar as during recalled clinical LBP episodes. In conclusion, unilateral and unisegmental experimental LBP exerts a generalized and widespread decrease in lumbar muscle activity during remission of recurrent LBP. This muscle response is consistent with previous observed patterns in healthy people subjected to the same experimental pain paradigm. It is striking that similar inhibitory patterns in response to pain could be observed, despite the presence of preexisting alterations in the lumbar musculature during remission of recurrent LBP. These results suggest that motor output can modify along the course of recurrent LBP.
Effects of acupressure on menstrual distress and low back pain in dysmenorrheic young adult women: an experimental study.
Chen, Huei-Mein; Wang, Hsiu-Hung; Chiu, Min-Huei; Hu, Hsou-Mei
The purpose of this study was to examine the effects of acupressure on menstrual distress and low back pain (LBP) in dysmenorrheic young adult women. In all, 129 female students, who had been experiencing dysmenorrhea with LBP during menstruation and who scored more than 4 points on the visual analog scale for pain, were randomly assigned to an experimental group and a control group. The experimental group (n = 65) received acupressure massage three times a week for 30 minutes on the sanyinjiao (SP6), ciliao (BL32), and taichong (Liver 3) acupoints. The control group (n = 64) received only a manual of menstrual health education without acupressure intervention. Data were collected at five time points: at baseline, 30 minutes, and 4, 8, and 12 months after the intervention. During the 12-month follow-up, the experimental group had significantly lower menstrual distress and LBP scores than the control group. Among 65 participants in the experimental group, 53 (82%) reported a moderate to high levels of menstrual distress, 51 (78%) reported moderate to high levels of LBP relief, and 49 (75%) reported moderate to high levels of satisfaction with acupressure. Our findings may serve as a reference for health care professionals and young women to improve self-care during menstruation and help further understand the therapeutic effects of acupressure on menstrual distress and LBP.
Pain Intensity after an Ice Pack Application Prior to Venipuncture among School-Age Children: An Experimental Study
ERIC Educational Resources Information Center
Alalo, Fadeelah Mansour Ahmed; Ahmad, Awatef El Sayed; El Sayed, Hoda Mohamed Nafee
Venipuncture and other invasive procedures as blood draws, intramuscular injections or heel pricks are the most commonly performed painful procedures in children. These can be a terrifying and painful experience for children and their families. The present study aimed to identify Pain intensity after an ice pack application prior to venipuncture…
Pain-related emotions modulate experimental pain perception and autonomic responses.
Rainville, Pierre; Bao, Quoc Viet Huynh; Chrétien, Pablo
The effect of emotions on pain perception is generally recognized but the underlying mechanisms remain unclear. Here, emotions related to pain were induced in healthy volunteers using hypnosis, during 1-min immersions of the hand in painfully hot water. In Experiment 1, hypnotic suggestions were designed to induce various positive or negative emotions. Compared to a control condition with hypnotic-relaxation, negative emotions produced robust increases in pain. In Experiment 2, induction of pain-related anger and sadness were found to increase pain. Pain increases were associated with increases in self-rated desire for relief and decreases in expectation of relief, and with increases in arousal, negative affective valence and decreases in perceived control. In Experiment 3, hypnotic suggestions specifically designed to increase and decrease the desire for relief produced increases and decreases in pain, respectively. In all three experiments, emotion-induced changes in pain were most consistently found on ratings of pain unpleasantness compared to pain intensity. Changes in pain-evoked cardiac responses (R-R interval decrease), measured in experiments 2 and 3, were consistent with changes in pain unpleasantness. Correlation and multiple regression analyses suggest that negative emotions and desire for relief influence primarily pain affect and that pain-evoked autonomic responses are strongly associated with pain affect. These results confirm the hypothesized influence of the desire for relief on pain perception, and particularly on pain affect, and support the functional relation between pain affect and autonomic nociceptive responses. This study provides further experimental confirmation that pain-related emotions influence pain perception and pain-related physiological responses.
Meta-analysis on brain representation of experimental dental pain.
Lin, C-S; Niddam, D M; Hsu, M-L
Functional magnetic resonance imaging (fMRI) has been widely used for investigating the brain representation associated with dental pain evoked by pulpal electrical stimulation. However, because of the heterogeneity of experimental designs and the small sample size of individual studies, the common brain representation regarding dental pain has remained elusive. We used imaging meta-analysis to investigate six dental pain-related fMRI studies (n = 87) and tested 3 hypotheses: (1) Dental pain is associated with the 'core' pain-related network; (2) pain-related brain activation is somatotopically organized in the somatosensory cortex; and (3) dental pain is associated with the cognitive-affective network related to pain. Qualitative and quantitative meta-analyses revealed: (1) common activation of the core pain-related network, including the somatosensory cortex, the insula, and the cingulate cortex; (2) inconsistency in somatotopically organized activation of the primary somatosensory cortex; and (3) common activation in the dorsolateral prefrontal cortex, suggesting a role of re-appraisal and coping in the experience of dental pain. In conclusion, fMRI combined with pulpal stimulation can effectively evoke activity in the pain-related network. The dental pain-related brain representation disclosed the mechanisms of how sensory and cognitive-affective factors shape dental pain, which will help in the development of more effective customized methods for central pain control.
Spontaneous Chronic Pain After Experimental Thoracotomy Revealed by Conditioned Place Preference: Morphine Differentiates Tactile Evoked Pain From Spontaneous Pain.
Hung, Ching-Hsia; Wang, Jeffrey Chi-Fei; Strichartz, Gary R
Chronic pain after surgery limits social activity, interferes with work, and causes emotional suffering. A major component of such pain is reported as resting or spontaneous pain with no apparent external stimulus. Although experimental animal models can simulate the stimulus-evoked chronic pain that occurs after surgery, there have been no studies of spontaneous chronic pain in such models. Here the conditioned place preference (CPP) paradigm was used to reveal resting pain after experimental thoracotomy. Male Sprague Dawley rats received a thoracotomy with 1-hour rib retraction, resulting in evoked tactile hypersensitivity, previously shown to last for at least 9 weeks. Intraperitoneal injections of morphine (2.5 mg/kg) or gabapentin (40 mg/kg) gave equivalent 2- to 3-hour-long relief of tactile hypersensitivity when tested 12 to 14 days postoperatively. In separate experiments, single trial CPP was conducted 1 week before thoracotomy and then 12 days (gabapentin) or 14 days (morphine) after surgery, followed the next day by 1 conditioning session with morphine or gabapentin, both versus saline. The gabapentin-conditioned but not the morphine-conditioned rats showed a significant preference for the analgesia-paired chamber, despite the equivalent effect of the 2 agents in relieving tactile allodynia. These results show that experimental thoracotomy in rats causes spontaneous pain and that some analgesics, such as morphine, that reduce evoked pain do not also relieve resting pain, suggesting that pathophysiological mechanisms differ between these 2 aspects of long-term postoperative pain. Perspective: Spontaneous pain, a hallmark of chronic postoperative pain, is demonstrated here in a rat model of experimental postthoracotomy pain, further validating the use of this model for the development of analgesics to treat such symptoms. Although stimulus-evoked pain was sensitive to systemic morphine, spontaneous pain was not, suggesting different mechanistic
Amantadine sulfate reduces experimental sensitization and pain in chronic back pain patients.
Kleinböhl, Dieter; Görtelmeyer, Roman; Bender, Hans-Joachim; Hölzl, Rupert
We investigated if established psychophysical measures of enhanced experimental sensitization in chronic musculoskeletal pain can be reduced by adjuvant treatment with a N-methyl-d-aspartate receptor antagonist, amantadine sulfate, and whether a reduction in sensitization might be accompanied by a concurrent improvement in clinical pain. Sensitization was evaluated by an experimental tonic heat model of short-term sensitization with concurrent subjective and behavioral psychophysical scaling. Twenty-six patients with chronic back pain were included in the randomized, double-blind, placebo-controlled study and received daily dosages of either placebo or 100 mg of amantadine sulfate during a 1-wk treatment. Participants completed quantitative sensory testing of pain thresholds and experimental sensitization before and after treatment and clinical pain ratings before, during, and after treatment. Experimental sensitization and clinical pain were reduced in patients receiving verum. Initially, experimental sensitization was enhanced in patients, with early sensitization at nonpainful intensities of contact heat and enhanced sensitization at painful intensities, as shown previously. After 1 wk of treatment, experimental sensitization was reduced with amantadine sulfate but not with placebo. We conclude that adjuvant chronic pain treatment with N-methyl-d-aspartate receptor antagonists might be beneficial for chronic pain if enhanced sensitization is involved and that the quantitative sensory test of temporal summation may be used to verify this.
The influence of experimentally induced pain on shoulder muscle activity.
Diederichsen, Louise Pyndt; Winther, Annika; Dyhre-Poulsen, Poul; Krogsgaard, Michael R; Nørregaard, Jesper
Muscle function is altered in painful shoulder conditions. However, the influence of shoulder pain on muscle coordination of the shoulder has not been fully clarified. The aim of the present study was to examine the effect of experimentally induced shoulder pain on shoulder muscle function. Eleven healthy men (range 22-27 years), with no history of shoulder or cervical problems, were included in the study. Pain was induced by 5% hypertonic saline injections into the supraspinatus muscle or subacromially. Seated in a shoulder machine, subjects performed standardized concentric abduction (0 degrees -105 degrees) at a speed of approximately 120 degrees/s, controlled by a metronome. During abduction, electromyographic (EMG) activity was recorded by intramuscular wire electrodes inserted in two deeply located shoulder muscles and by surface-electrodes over six superficially located shoulder muscles. EMG was recorded before pain, during pain and after pain had subsided and pain intensity was continuously scored on a visual analog scale (VAS). During abduction, experimentally induced pain in the supraspinatus muscle caused a significant decrease in activity of the anterior deltoid, upper trapezius and the infraspinatus and an increase in activity of lower trapezius and latissimus dorsi muscles. Following subacromial injection a significantly increased muscle activity was seen in the lower trapezius, the serratus anterior and the latissimus dorsi muscles. In conclusion, this study shows that acute pain both subacromially and in the supraspinatus muscle modulates coordination of the shoulder muscles during voluntary movements. During painful conditions, an increased activity was detected in the antagonist (latissimus), which support the idea that localized pain affects muscle activation in a way that protects the painful structure. Further, the changes in muscle activity following subacromial pain induction tend to expand the subacromial space and thereby decrease the load
Verbally reinforcing pain reports: an experimental test of the operant model of chronic pain.
Jolliffe, Christopher D; Nicholas, Michael K
Effective treatments for chronic pain have been based on the operant model for chronic pain, which holds that pain behaviours can be operantly controlled by various reinforcers. Support for the operant model comes primarily from treatment/outcome studies which report significant reductions in pain behaviours in chronic pain patients, but fail to demonstrate the underlying operant thesis that various reinforcers play a significant role in the establishment and maintenance of pain behaviours. In an experimental test of this hypothesis, the pain reports of forty-six healthy undergraduate students were measured over two sets of fifteen trials, in which the pressure from a blood-pressure cuff applied to their arm either remained stable or decreased over time. Half of the subjects received positive verbal reinforcement from the experimenter after each trial if their report of pain intensity exceeded that of the previous trial. Overall, the mean pain reports of reinforced subjects were significantly greater than those of the non-reinforced subjects both when the intensity of the cuff was stable over trials, and when it decreased, as expected. These results provide support for the operant model of chronic pain. The clinical and theoretical implications of these results for the operant model of chronic pain are discussed, and suggestions for future research are made.
Pain referral and regional deep tissue hyperalgesia in experimental human hip pain models.
Izumi, Masashi; Petersen, Kristian Kjær; Arendt-Nielsen, Lars; Graven-Nielsen, Thomas
Hip disorder patients typically present with extensive pain referral and hyperalgesia. To better understand underlying mechanisms, an experimental hip pain model was established in which pain referrals and hyperalgesia could be studied under standardized conditions. In 16 healthy subjects, pain was induced by hypertonic saline injection into the gluteus medius tendon (GMT), adductor longus tendon (ALT), or gluteus medius muscle (GMM). Isotonic saline was injected contralaterally as control. Pain intensity was assessed on a visual analogue scale (VAS), and subjects mapped the pain distribution. Before, during, and after injections, passive hip joint pain provocation tests were completed, together with quantitative sensory testing as follows: pressure pain thresholds (PPTs), cuff algometry pain thresholds (cuff PPTs), cutaneous pin-prick sensitivity, and thermal pain thresholds. Hypertonic saline injected into the GMT resulted in higher VAS scores than hypertonic injections into the ALT and GMM (P<.05). Referred pain areas spread to larger parts of the leg after GMT and GMM injections compared with more regionalized pain pattern after ALT injections (P<.05). PPTs at the injection site were decreased after hypertonic saline injections into GMT and GMM compared with baseline, ALT injections, and isotonic saline. Cuff PPTs from the thigh were decreased after hypertonic saline injections into the ALT compared with baseline, GMT injections, and isotonic saline (P<.05). More subjects had positive joint pain provocation tests after hypertonic compared with isotonic saline injections (P<.05), indicating that this provocation test also assessed hyperalgesia in extra-articular soft tissues. The experimental models may open for better understanding of pain mechanisms associated with painful hip disorders.
Effects of experimental craniofacial pain on fine jaw motor control: a placebo-controlled double-blinded study.
Kumar, Abhishek; Castrillon, Eduardo; Svensson, Krister G; Baad-Hansen, Lene; Trulsson, Mats; Svensson, Peter
The aim of the experiment was to test the hypothesis that experimental pain in the masseter muscle or temporomandibular joint (TMJ) would perturb the oral fine motor control, reflected in bigger variability of bite force values and jaw muscle activity, during repeated splitting of food morsels. Twenty healthy volunteers participated in four sessions. An intervention was made by injection of either 0.2 ml of monosodium glutamate/isotonic saline (MSG/IS) (randomized) in either the masseter or TMJ (randomized). The participants were asked to hold and split a flat-faced placebo tablet with their anterior teeth, thirty times each at baseline, during intervention and post-intervention. Pain was measured using a 0-10 visual analog scale. The force applied by the teeth to "hold" and "split" the tablet along with the corresponding electromyographic (EMG) activity of the jaw muscles and subject-based reports on perception of pain was recorded. The data analysis included a three-way analysis of variance model. The peak pain intensity was significantly higher during the painful MSG injections in the TMJ (6.1 ± 0.4) than the injections in masseter muscle (5.5 ± 0.5) (P = 0.037). Variability of hold force was significantly smaller during the MSG injection than IS injection in the masseter (P = 0.024). However, there was no significant effect of intervention on the variability of split force during the masseter injections (P = 0.769) and variability of hold and split force during the TMJ injections (P = 0.481, P = 0.545). The variability of the EMG activity of the jaw muscles did not show significant effects of intervention. Subject-based reports revealed that pain did not interfere in the ability to hold the tablet in 57.9 and 78.9 %, and the ability to split the tablet in 78.9 and 68.4 %, of the participants, respectively, during painful masseter and TMJ injections. Hence, experimental pain in the masseter muscle or TMJ did not have any robust effect in terms of bigger
The effect of experimentally-induced subacromial pain on proprioception.
Sole, Gisela; Osborne, Hamish; Wassinger, Craig
Shoulder injuries may be associated with proprioceptive deficits, however, it is unknown whether these changes are due to the experience of pain, tissue damage, or a combination of these. The aim of this study was to investigate the effect of experimentally-induced sub-acromial pain on proprioceptive variables. Sub-acromial pain was induced via hypertonic saline injection in 20 healthy participants. Passive joint replication (PJR) and threshold to detection of movement direction (TTDMD) were assessed with a Biodex System 3 Pro isokinetic dynamometer for baseline control, experimental pain and recovery control conditions with a starting position of 60° shoulder abduction. The target angle for PJR was 60° external rotation, starting from 40°. TTDMD was tested from a position of 20° external rotation. Repeated measures ANOVAs were used to determine differences between PJR absolute and variable errors and TTDMD for the control and experimental conditions. Pain was elicited with a median 7 on the Numeric Pain Rating Scale. TTDMD was significantly decreased for the experimental pain condition compared to baseline and recovery conditions (≈30%, P = 0.003). No significant differences were found for absolute (P = 0.152) and variable (P = 0.514) error for PJR. Movement sense was enhanced for the experimental sub-acromial pain condition, which may reflect protective effects of the central nervous system in response to the pain. Where decreased passive proprioception is observed in shoulders with injuries, these may be due to a combination of peripheral tissue injury and neural adaptations that differ from those due to acute pain.
Experimentally induced pain perception is acutely reduced by aerobic exercise in people with chronic low back pain.
Hoffman, Martin D; Shepanski, Melissa A; Mackenzie, Sean P; Clifford, Philip S
This study examined whether subjects with chronic low back pain demonstrate exercise-induced analgesia to experimentally induced pressure pain. We employed a repeated measures design to study eight subjects with chronic low back pain (mean +/- standard deviation age = 40 +/- 10, duration of pain = 7 +/- 4 years). Pain ratings were measured immediately before and 2 minutes and 32 minutes after 25 minutes of cycle ergometry (5 minutes at 50% peak oxygen uptake, then 20 minutes at 70% peak oxygen uptake). We based the pain ratings on subject input on a visual analog scale at 10-second intervals during the 2-minute pressure pain stimulus to the nondominant index finger. Compared with preexercise values, pain ratings were significantly (p < 0.05) decreased after exercise at both 2 and 32 minutes postexercise. We conclude that pressure pain perception can be reduced for more than 30 minutes following aerobic exercise from leg cycling among people with chronic low back pain.
Ischemic compression and joint mobilisation for the treatment of nonspecific myofascial foot pain: findings from two quasi-experimental before-and-after studies
Hains, Guy; Boucher, Pierre B.; Lamy, Anne-Marie
Objective: The aim of this study was to evaluate the efficacy of myofascial therapy involving ischemic compression on trigger points in combination with mobilization therapy on patients with chronic nonspecific foot pain. Study design: Two quasi-experimental before-and-after studies involving two different baseline states. Method: Foot pain patients at a private clinic were divided into two separate cohorts: A, custom orthotic users; and B, non-users. In Study A, 31 users received 15 experimental treatments consisting of ischemic compressions on trigger points and mobilization of articulations through the foot immediately after study enrollment. In study B, ten non-users were prescribed a soft prefabricated insole and were monitored for five weeks before subsequently receiving 15 experimental treatments after the initial five-week delay. Outcome measures: The Foot Function Index (FFI) and patients' perceived improvement score (PIS) on a scale from 0% to 100%. Results: The Study A group (n=31) maintained a significant reduction in the FFI at all three follow-up evaluations. Mean improvement from baseline in FFI was 47%, 49% and 56% at 0, 1 and 6 months, respectively, post-treatment. Mean PIS was 58%, 57%, and 58%, again at 0, 1 and 6 months post-treatment. For the Study B group, mean improvement in FFI was only 19% after the monitoring period, and 64% after the experimental treatment period. Mean PIS was 31% after monitoring, and 78% after experimental treatment. In repeated measures analyses, experimental treatment was associated with a significant main effect in both of these before-and after studies (all P values<0.01). Conclusion: Combined treatment involving ischemic compression and joint mobilization for chronic foot pain is associated with significant improvements in functional and self-perceived improvement immediately and at up to six-months post-treatment. Further validation of this treatment approach within a randomized controlled trial is needed. PMID
Interaction between histamine-induced itch and experimental muscle pain.
Wasner, G; Schwarz, K; Schattschneider, J; Binder, A; Jensen, T S; Baron, R
Itch sensation can be inhibited by simultaneously applied cutaneous pain at the same skin site via a central mechanism. Deep muscle pain is often associated with sensory changes in the corresponding dermatome. We investigated whether experimentally induced muscle pain has any influence on histamine-induced itch and vice versa in a double blind placebo-controlled study. Experiments were performed in 18 healthy subjects. In nine individuals control iontophoresis of histamine into the forearm produced a distinct itch sensation. Another nine individuals participated in an additional experiment in which histamine and saline were iontophoresed on the forearm in a randomized double-blinded two-way crossover design after intramuscular injection of capsaicin into the ipsilateral brachioradial muscle. Capsaicin-induced muscle pain reduced itch sensation significantly. In contrast, capsaicin-induced muscle pain increased significantly after cutaneous histamine application compared to muscle pain after iontophoresis of saline (placebo). These novel data indicate that muscle pain inhibits itch and histamine increases muscle pain. A bi-directional interaction between cutaneous histamine-sensitive afferents and nociceptive muscle afferents via central mechanisms is suggested.
Assessing analgesic actions of opioids by experimental pain models in healthy volunteers – an updated review
Staahl, Camilla; Olesen, Anne Estrup; Andresen, Trine; Arendt-Nielsen, Lars; Drewes, Asbjørn Mohr
AIM Experimental pain models may help to evaluate the mechanisms of action of analgesics and target the clinical indications for their use. This review addresses how the efficacy of opioids can be assessed in human volunteers using experimental pain models. The drawback with the different study designs is also discussed. METHOD A literature search was completed for randomized controlled studies which included human experimental pain models, healthy volunteers and opioids. RESULTS Opioids with a strong affinity for the µ-opioid receptor decreased the sensation in a variety of experimental pain modalities, but strong tonic pain was attenuated more than short lasting pain and non-painful sensations. The effects of opioids with weaker affinity for the µ-opioid receptor were detected by a more narrow range of pain models, and the assessment methods needed to be more sensitive. CONCLUSION The way the pain is induced, assessed and summarized is very important for the sensitivity of the pain models. This review gives an overview of how different opioids perform in experimental pain models. Generally experimental pain models need to be designed with careful consideration of pharmacological mechanisms and pharmacokinetics of analgesics. This knowledge can aid the decisions needed to be taken when designing experimental pain studies for compounds entering phase 1 clinical trials. PMID:19694733
Effects of Extracorporeal Shock Wave Therapy on Pain in Patients With Chronic Refractory Coccydynia: A Quasi-Experimental Study
Haghighat, Shila; Mashayekhi Asl, Mahboobeh
Background Several nonsurgical and surgical treatment modalities are available for patients with chronic coccydynia, with controversial results. Extracorporeal shock wave therapy (ECSWT) is effective in the treatment of many musculoskeletal disorders; however, it has not been tested for chronic coccydynia. Objectives We performed the current study to determine the effects of ECSWT on pain in patients with chronic coccydynia. Patients and Methods This quasi-interventional clinical study included 10 patients with chronic coccydynia without acute fracture. All the patients received ECSWT with a radial probe delivering 3,000 shock waves of 2 bar per session at 21 Hz frequency directed to the coccyx. Each patient received four sessions of ECSWT at one-week intervals. The pain severity was recorded according to the visual analog scale (VAS) at one, two, three, and four weeks after initiation of therapy. The VAS score was also evaluated at one and six months after ending the therapy. Results Most of the participants were women (90.0%), and the participants' mean age was 39.1 ± 9.1 (ranging from 28 to 52) years. The VAS score did not decrease significantly seven months after therapy when compared to baseline (3.3 ± 3.6 vs. 7.3 ± 2.1; P = 0.011). However, the VAS score at two months (2.6 ± 2.9 vs. 7.3 ± 2.1; P = 0.007) and at four weeks (3.2 ± 2.8 vs. 7.3 ± 2.1; P = 0.007) significantly decreased when compared to baseline. The decrease in VAS scores was not persistent after cessation of the therapy. Conclusions ECSWT is an effective modality in relieving the pain intensity in patients with refractory chronic coccydynia for the early period after intervention. PMID:27843777
Levin, L M; Cooper, S A; Betts, N J; Wedell, D; Hermann, D G; Lamp, C; Secreto, S A; Hersh, E V
Ketoprofen is a nonsteroidal antiinflammatory drug, recently approved as an over-the-counter (OTC) analgesic at a 12.5 mg dosage strength. This is the first published study which explores the analgesic efficacy and safety of ketoprofen 12.5 mg in patients experiencing pain following the removal of impacted third molars. This study was single-dose, double-blind and randomized utilizing a 6-hour in-patient evaluation period. Patients ingested a single dose of ketoprofen 12.5 mg (n = 30), ketoprofen 37.5 mg (n = 32) or placebo (n = 15) when their post-surgical pain reached at least a moderate intensity on a 5-point categorical (CAT) scale and greater than 50 mm on a 100 mm visual analog scale (VAS). Measures of pain intensity and relief were gathered every 20 minutes for the first 2 hours, and then hourly from hours 3 through 6. Adverse drug reactions were also recorded as they occurred. Both dosages of ketoprofen were significantly more efficacious than placebo (two way ANOVAs, p < 0.05). For pain intensity difference (PID) and pain relief, the 12.5 mg dose exhibited statistical superiority from hours 1 through 3, while the 37.5 mg dose exhibited statistical superiority from 40 minutes through 4 hours. Ketoprofen 37.5 mg was significantly more efficacious than the 12.5 mg dose only at 40 minutes for PID(VAS) and relief, and at 60 minutes for PID(VAS). Both ketoprofen dosages displayed significantly greater 3-hr, 4-hr and 6-hr summary analgesic measures (SPID(VAS), SPID(CAT), TOTPAR) than placebo, with the exception of the 6-hr SPID(CAT) measure for ketoprofen 12.5 mg. No serious side effects were observed in this study. We conclude that ketoprofen in a dose range of 12.5 mg to 37.5 mg is a safe and effective analgesic for the relief of post-operative dental pain.
Effects of hypnotic analgesia and hypnotizability on experimental ischemic pain.
DeBenedittis, G; Panerai, A A; Villamira, M A
Mechanisms of hypnotic analgesia are still poorly understood and conflicting data are reported regarding the underlying neurochemical correlates. The present study was designed to investigate the effects of hypnotically induced analgesia and hypnotizability on experimental ischemic pain, taking into account pain and distress tolerance as well as the neurochemical correlates. 11 high hypnotizable Ss and 10 low hypnotizable Ss, as determined by scores on the Stanford Hypnotic Susceptibility Scale, Form C (Weitzenhoffer & E. R. Hilgard, 1962), were administered an ischemic pain test in both waking and hypnotic conditions. The following variables were measured: (a) pain and distress tolerance, (b) anxiety levels, and (c) plasma concentrations of beta-endorphin and adrenocorticotropic hormone (ACTH). Results confirmed significant increases of pain and distress tolerance during hypnosis as compared to the waking state, with positive correlations between pain and distress relief and hypnotizability. Moreover, a hypnotically induced dissociation between the sensory-discriminative and the affective-motivational dimensions of pain experience was found, but only in high hypnotizable Ss. Hypnotic analgesia was unrelated to anxiety reduction and was not mediated either by endorphins or by ACTH.
Differences in pain-related fear acquisition and generalization: an experimental study comparing patients with fibromyalgia and healthy controls.
Meulders, Ann; Jans, Anne; Vlaeyen, Johan W S
Anomalies in fear learning, such as failure to inhibit fear to safe stimuli, lead to sustained anxiety, which in turn may augment pain. In the same vein, stimulus generalization is adaptive as it enables individuals to extrapolate the predictive value of 1 stimulus to similar stimuli. However, when fear spreads in an unbridled way to novel technically safe stimuli, stimulus generalization becomes maladaptive and may lead to dysfunctional avoidance behaviors and culminate in severe pain disability. In a voluntary movement conditioning paradigm, we compared the acquisition and generalization of pain-related fear in patients with fibromyalgia (FM) and healthy controls. During acquisition, participants received predictable pain in 1 context (ie, 1 movement predicts pain, whereas another does not), and unpredictable pain in another (ie, pain never contingent upon movement). Fear generalization to novel movements (resembling the original painful or nonpainful movement) was tested in both contexts. Results indicated that the FM group showed slower differential acquisition of pain-related fear in the predictable context, and more contextual pain-related fear in the unpredictable context. Fear of movement-related pain spreads selectively to novel movements similar to the original painful movement, and not to those resembling the nonpainful movement in the healthy controls, but nondifferential fear generalization was observed in FM. As expected, in the unpredictable context, we also observed nondifferential fear generalization; this effect was more pronounced in FM. Given the status of overgeneralization as a plausible transdiagnostic pathogenic marker, we believe that this research might increase our knowledge about pathogenesis of musculoskeletal widespread pain.
Experimental pain phenotyping in community-dwelling individuals with knee osteoarthritis.
Cardoso, Josue S; Riley, Joseph L; Glover, Toni; Sibille, Kimberly T; Bartley, Emily J; Goodin, Burel R; Bulls, Hailey W; Herbert, Matthew; Addison, Adriana S; Staud, Roland; Redden, David T; Bradley, Laurence A; Fillingim, Roger B; Cruz-Almeida, Yenisel
Pain among individuals with knee osteoarthritis (OA) is associated with significant disability in older adults, and recent evidence demonstrates enhanced experimental pain sensitivity. Although previous research showed considerable heterogeneity in the OA clinical pain presentation, less is known regarding the variability in responses to experimental pain. The present study included individuals with knee OA (n = 292) who participated in the Understanding Pain and Limitations in Osteoarthritic Disease study and completed demographic and psychological questionnaires followed by a multimodal quantitative sensory testing (QST) session. Quantitative sensory testing measures were subjected to variable reduction procedures to derive pain sensitivity index scores, which in turn were entered into a cluster analysis. Five clusters were significantly different across all pain sensitivity index variables (P < 0.001) and were characterized by: (1) low pain sensitivity to pressure pain (N = 39); (2) average pain sensitivity across most modalities (N = 88); (3) high temporal summation of punctate pain (N = 38); (4) high cold pain sensitivity (N = 80); and (5) high sensitivity to heat pain and temporal summation of heat pain (N = 41). Clusters differed significantly by race, gender, somatic reactivity, and catastrophizing (P < 0.05). Our findings support the notion that there are distinct subgroups or phenotypes based on experimental pain sensitivity in community-dwelling older adults with knee OA, expanding previous findings of similar cluster characterizations in healthy adults. Future research is needed to further understand the pathophysiological mechanisms underlying pain within these subgroups, which may be of added value in tailoring effective treatments for people with OA.
Ultrasound guided, painful electrical stimulation of lumbar facet joint structures: an experimental model of acute low back pain.
O'Neill, Søren; Graven-Nielsen, Thomas; Manniche, Claus; Arendt-Nielsen, Lars
Quantitative sensory testing has indicated generalized muscle hyperalgesia in patients with chronic low back pain. The temporal development of such hyperalgesia is not well understood. The aim of the present study was to demonstrate whether generalized muscle hyperalgesia can develop within minutes of acute low back pain using a new experimental model of lumbar facet joint pain. Thirteen healthy volunteers were included and baseline pressure pain thresholds were assessed at eight separate sites, outside the area of evoked low back and referred pain. Using ultrasonography, two electrode needles were placed either side of a lumbar facet joint (right L3-4) and used to induce experimental low back pain for 10 min with continuous stimulation. Thresholds, stimulus-response relationships, distribution and quality of the electrically induced pain were recorded. Electrical facet joint stimulation induced low back pain and pain referral into the anterior leg, ipsilaterally, proximal to the knee, similar to what is observed clinically. Pressure pain thresholds did not change significantly before, during and after facet joint stimulation. In conclusion, we describe a novel model of acute experimental low back pain and demonstrate that generalized hyperalgesia did not develop within minutes of acute low back pain.
Nonpainful wide-area compression inhibits experimental pain.
Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena
Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM.
Nonpainful wide-area compression inhibits experimental pain
Honigman, Liat; Bar-Bachar, Ofrit; Yarnitsky, David; Sprecher, Elliot; Granovsky, Yelena
Abstract Compression therapy, a well-recognized treatment for lymphoedema and venous disorders, pressurizes limbs and generates massive non-noxious afferent sensory barrages. The aim of this study was to study whether such afferent activity has an analgesic effect when applied on the lower limbs, hypothesizing that larger compression areas will induce stronger analgesic effects, and whether this effect correlates with conditioned pain modulation (CPM). Thirty young healthy subjects received painful heat and pressure stimuli (47°C for 30 seconds, forearm; 300 kPa for 15 seconds, wrist) before and during 3 compression protocols of either SMALL (up to ankles), MEDIUM (up to knees), or LARGE (up to hips) compression areas. Conditioned pain modulation (heat pain conditioned by noxious cold water) was tested before and after each compression protocol. The LARGE protocol induced more analgesia for heat than the SMALL protocol (P < 0.001). The analgesic effect interacted with gender (P = 0.015). The LARGE protocol was more efficient for females, whereas the MEDIUM protocol was more efficient for males. Pressure pain was reduced by all protocols (P < 0.001) with no differences between protocols and no gender effect. Conditioned pain modulation was more efficient than the compression-induced analgesia. For the LARGE protocol, precompression CPM efficiency positively correlated with compression-induced analgesia. Large body area compression exerts an area-dependent analgesic effect on experimental pain stimuli. The observed correlation with pain inhibition in response to robust non-noxious sensory stimulation may suggest that compression therapy shares similar mechanisms with inhibitory pain modulation assessed through CPM. PMID:27152691
Hypnosis and Local Anesthesia for Dental Pain Relief-Alternative or Adjunct Therapy?-A Randomized, Clinical-Experimental Crossover Study.
Wolf, Thomas Gerhard; Wolf, Dominik; Callaway, Angelika; Below, Dagna; d'Hoedt, Bernd; Willershausen, Brita; Daubländer, Monika
This prospective randomized clinical crossover trial was designed to compare hypnosis and local anesthesia for experimental dental pain relief. Pain thresholds of the dental pulp were determined. A targeted standardized pain stimulus was applied and rated on the Visual Analogue Scale (0-10). The pain threshold was lower under hypnosis (58.3 ± 17.3, p < .001), maximal (80.0) under local anesthesia. The pain stimulus was scored higher under hypnosis (3.9 ± 3.8) than with local anesthesia (0.0, p < .001). Local anesthesia was superior to hypnosis and is a safe and effective method for pain relief in dentistry. Hypnosis seems to produce similar effects observed under sedation. It can be used in addition to local anesthesia and in individual cases as an alternative for pain control in dentistry.
Postural Responses to a Suddenly Released Pulling Force in Older Adults with Chronic Low Back Pain: An Experimental Study
Lee, Pei-Yun; Lin, Sang-I; Liao, Yu-Ting; Lin, Ruey-Mo; Hsu, Che-Chia; Huang, Kuo-Yuan; Chen, Yi-Ting
Chronic low back pain (CLBP), one of the most common musculoskeletal conditions in older adults, might affect balance and functional independence. The purpose of this study was to investigate the postural responses to a suddenly released pulling force in older adults with and without CLBP. Thirty community-dwelling older adults with CLBP and 26 voluntary controls without CLBP were enrolled. Participants were required to stand on a force platform while, with one hand, they pulled a string that was fastened at the other end to a 2-kg or to a 4-kg force in the opposite direction at a random order. The number of times the participants lost their balance and motions of center of pressure (COP) when the string was suddenly released were recorded. The results demonstrated that although the loss of balance rates for each pulling force condition did not differ between groups, older adults with CLBP had poorer postural responses: delayed reaction, larger displacement, higher velocity, longer path length, and greater COP sway area compared to the older controls. Furthermore, both groups showed larger postural responses in the 4-kg pulling force condition. Although aging is generally believed to be associated with declining balance and postural control, these findings highlight the effect of CLBP on reactive balance when responding to an externally generated force in an older population. This study also suggests that, for older adults with CLBP, in addition to treating them for pain and disability, reactive balance evaluation and training, such as reaction and movement strategy training should be included in their interventions. Clinicians and older patients with CLBP need to be made aware of the significance of impaired reactive balance and the increased risk of falls when encountering unexpected perturbations. PMID:27622646
The Effect of Intrathecal Administration of Muscimol on Modulation of Neuropathic Pain Symptoms Resulting from Spinal Cord Injury; an Experimental Study
Hosseini, Marjan; Karami, Zohreh; Janzadenh, Atousa; Jameie, Seyed Behnamedin; Haji Mashhadi, Zahra; Yousefifard, Mahmoud; Nasirinezhad, Farinaz
Introduction: Neuropathic pain can be very difficult to treat and it is one of the important medical challenging about pain treatments. Muscimol as a new agonist of gamma-Aminobutyric acid receptor type A (GABAA) have been introduced for pain management. Thus, the present study was performed to evaluate the pain alleviating effect of intrathecal injection of different doses of muscimol as GABAA receptor agonist in spinal cord injury (SCI) model of neuropathic pain. Methods: In the present experimental study, male Wistar rats were treated by muscimol 0.01, 0.1 or 1 µg/10ul, intrathecally (i.t.) three weeks after induction of spinal cord injury using compression injury model. Neuropathic pain symptoms were assessed at before treatment, 15 minutes, one hour and three hours after muscimol administration. The time of peak effect and optimum dosage was assessed by repeated measures analysis of variance and analysis of covariance, respectively. Results: Muscimol with the dose of 0.01 µg in 15 minutes caused to improve the thermal hyperalgesia (df: 24, 5; F= 6.6; p<0.001), mechanical hyperalgesia (df: 24, 5; F= 7.8; p<0.001), cold allodynia (df: 24, 5; F= 6.96; p<0.001), and mechanical allodynia (df: 24, 5; F= 15.7; p<0.001). The effect of doses of 0.1 µg and 1 µg were also significant. In addition, the efficacy of different doses of muscimol did not have difference on thermal hyperalgesia (df: 24, 5; F= 1.52; p= 0.24), mechanical hyperalgesia (df: 24, 5; F= 0.3; p= -0.75), cold allodynia (df: 24, 5; F= 0.8; p= -0.56), and mechanical allodynia (df: 24, 5; F= 1.75; p= 0.86). Conclusion: The finding of the present study revealed that using muscimol with doses of 0.01µg, 0.1µg, and 1 µg reduces the symptoms of neuropathic pain. In addition, the effect of GABAA agonist is short term and its effectiveness gradually decreases by time. PMID:26495371
Pain perception in people with Down syndrome: a synthesis of clinical and experimental research
McGuire, Brian E.; Defrin, Ruth
People with an intellectual disability experience both acute and chronic pain with at least the same frequency as the general population. However, considerably less is known about the pain perception of people with Down syndrome. In this review paper, we evaluated the available clinical and experimental evidence. Some experimental studies of acute pain have indicated that pain threshold was higher than normal but only when using a reaction time method to measure pain sensitivity. However, when reaction time is not part of the calculation of the pain threshold, pain sensitivity in people with Down syndrome is in fact lower than normal (more sensitive to pain). Clinical studies of chronic pain have shown that people with an intellectual disability experience chronic pain and within that population, people with Down syndrome also experience chronic pain, but the precise prevalence of chronic pain in Down syndrome has yet to be established. Taken together, the literature suggests that people with Down syndrome experience pain, both acute and chronic, with at least the same frequency as the rest of the population. Furthermore, the evidence suggests that although acute pain expression appears to be delayed, once pain is registered, there appears to be a magnified pain response. We conclude by proposing an agenda for future research in this area. PMID:26283936
Experimental pain responses in children with chronic pain and in healthy children: How do they differ?
Tsao, Jennie CI; Evans, Subhadra; Seidman, Laura C; Zeltzer, Lonnie K
BACKGROUND: Extant research comparing laboratory pain responses of children with chronic pain with healthy controls is mixed, with some studies indicating lower pain responsivity for controls and others showing no differences. Few studies have included different pain modalities or assessment protocols. OBJECTIVES: To compare pain responses among 26 children (18 girls) with chronic pain and matched controls (mean age 14.8 years), to laboratory tasks involving thermal heat, pressure and cold pain. Responses to cold pain were assessed using two different protocols: an initial trial of unspecified duration and a second trial of specified duration. METHODS: Four trials of pressure pain and of thermal heat pain stimuli, all of unspecified duration, were administered, as well as the two cold pain trials. Heart rate and blood pressure were assessed at baseline and after completion of the pain tasks. RESULTS: Pain tolerance and pain intensity did not differ between children with chronic pain and controls for the unspecified trials. For the specified cold pressor trial, 92% of children with chronic pain completed the entire trial compared with only 61.5% of controls. Children with chronic pain exhibited a trend toward higher baseline and postsession heart rate and reported more anxiety and depression symptoms compared with control children. CONCLUSIONS: Contextual factors related to the fixed trial may have exerted a greater influence on pain tolerance in children with chronic pain relative to controls. Children with chronic pain demonstrated a tendency toward increased arousal in anticipation of and following pain induction compared with controls. PMID:22518373
Sex differences in experimental pain among healthy children: a systematic review and meta-analysis.
Boerner, Katelynn E; Birnie, Kathryn A; Caes, Line; Schinkel, Meghan; Chambers, Christine T
Sex differences in response to experimental pain are commonly reported in systematic reviews in the adult literature. The objective of the present research was to conduct a systematic review and meta-analysis of sex differences in healthy children's responses to experimental pain (e.g., cold pressor, heat pain, pressure pain) and, where possible, to conduct analyses separately for children and adolescents. A search was conducted of electronic databases for published papers in English of empirical research using experimental pain tasks to examine pain-related outcomes in healthy boys and girls between 0 and 18 years of age. Eighty articles were eligible for inclusion and were coded to extract information relevant to sex differences. The systematic review indicated that, across different experimental pain tasks, the majority of studies reported no significant differences between boys and girls on pain-related outcomes. However, the meta-analysis of available combined data found that girls reported significantly higher cold pressor pain intensity compared to boys in studies where the mean age of participants was greater than 12 years. Additionally, a meta-analysis of heat pain found that boys had significantly higher tolerance than girls overall, and boys had significantly higher heat pain threshold than girls in studies where the mean age of participants was 12 years or younger. These findings suggest that developmental stage may be relevant for understanding sex differences in pain.
Transcranial direct current stimulation over the opercular somatosensory region does not influence experimentally induced pain: a triple blind, sham-controlled study
Koyama, Soichiro; Nakagawa, Kei
Transcranial magnetic stimulation (TMS) over the opercular somatosensory region (OP), which includes the secondary somatosensory cortex and the insular cortex, suppresses pain sensation. However, whether transcranial direct current stimulation (tDCS) over the OP has a similar effect on pain sensation remains unknown. We examined whether pain sensation would be suppressed by tDCS over the OP. Our experiment with a triple-blind, sham-controlled, crossover design involved 12 healthy participants. Participants were asked to rate their subjective pain intensity during and after three types of bihemispheric tDCS: right anodal/left cathodal OP tDCS, left anodal/right cathodal OP tDCS (2 mA, 12 min), and sham tDCS (15 s). Pain stimuli were alternately applied to the dorsum of each index finger using intraepidermal electrical stimulation. We observed no significant effect of tDCS over the OP on the perception of experimentally induced pain. Subjective pain intensity did not differ significantly between the three tDCS conditions. The present null results have crucial implications for the selection of optimal stimulation regions and parameters for clinical pain treatment. PMID:27984542
Human experimental pain models: A review of standardized methods in drug development
Reddy, K. Sunil kumar; Naidu, M. U. R.; Rani, P. Usha; Rao, T. Ramesh Kumar
Human experimental pain models are essential in understanding the pain mechanisms and appear to be ideally suited to test analgesic compounds. The challenge that confronts both the clinician and the scientist is to match specific treatments to different pain-generating mechanisms and hence reach a pain treatment tailored to each individual patient. Experimental pain models offer the possibility to explore the pain system under controlled settings. Standardized stimuli of different modalities (i.e., mechanical, thermal, electrical, or chemical) can be applied to the skin, muscles, and viscera for a differentiated and comprehensive assessment of various pain pathways and mechanisms. Using a multimodel-multistructure testing, the nociception arising from different body structures can be explored and modulation of specific biomarkers by new and existing analgesic drugs can be profiled. The value of human experimental pain models is to link animal and clinical pain studies, providing new possibilities for designing successful clinical trials. Spontaneous pain, the main compliant of the neuropathic patients, but currently there is no human model available that would mimic chronic pain. Therefore, current human pain models cannot replace patient studies for studying efficacy of analgesic compounds, although being helpful for proof-of-concept studies and dose finding. PMID:23626642
Experimental reduction of pain catastrophizing modulates pain report but not spinal nociception as verified by mediation analyses.
Terry, Ellen L; Thompson, Kathryn A; Rhudy, Jamie L
Pain catastrophizing is associated with enhanced pain; however, the mechanisms by which it modulates pain are poorly understood. Evidence suggests that catastrophizing modulates supraspinal processing of pain but does not modulate spinal nociception (as assessed by nociceptive flexion reflex [NFR]). Unfortunately, most NFR studies have been correlational. To address this, this study experimentally reduced catastrophizing to determine whether it modulates spinal nociception (NFR). Healthy pain-free participants (N = 113) were randomly assigned to a brief 30-minute catastrophizing reduction manipulation or a control group that received pain education. Before and after manipulations, 2 types of painful stimuli were delivered to elicit (1) NFR (single trains of stimuli) and (2) temporal summation of NFR (3 stimulations at 2 Hz). After each set of stimuli, participants were asked to report their pain intensity and unpleasantness, as well as their situation-specific catastrophizing. Manipulation checks verified that catastrophizing was effectively reduced. Furthermore, pain intensity and unpleasantness to both stimulation types were reduced by the catastrophizing manipulation, effects that were mediated by catastrophizing. Although NFRs were not affected by the catastrophizing manipulation, temporal summation of NFR was reduced. However, this effect was not mediated by catastrophizing. These results indicate that reductions in catastrophizing lead to reductions in pain perception but do not modulate spinal nociception and provides further evidence that catastrophizing modulates pain at the supraspinal, not the spinal, level.
Sex differences in experimental measures of pain sensitivity and endogenous pain inhibition
Bulls, Hailey W; Freeman, Emily L; Anderson, Austen JB; Robbins, Meredith T; Ness, Timothy J; Goodin, Burel R
It has been suggested that increased pain sensitivity and disruption of endogenous pain inhibitory processes may account, at least in part, for the greater prevalence and severity of chronic pain in women compared to men. However, previous studies addressing this topic have produced mixed findings. This study examined sex differences in pain sensitivity and inhibition using quantitative sensory testing (QST), while also considering the influence of other important factors such as depressive symptoms and sleep quality. Healthy men (n=24) and women (n=24) each completed a QST battery. This battery included an ischemic pain task (IPT) that used a submaximal effort tourniquet procedure as well as a conditioned pain modulation (CPM) procedure for the assessment of endogenous pain inhibition. Prior to QST, participants completed the Center for Epidemiologic Studies Depression Scale and the Pittsburgh Sleep Quality Index. Analyses revealed significant sex differences for the ischemic pain task and the conditioned pain modulation procedure, such that women tolerated the ischemic pain for a shorter amount of time and demonstrated less pain inhibition compared with men. This remained true even when accounting for sex differences in depressive symptoms and sleep quality. The results of this study suggest that women may be more pain sensitive and possess less-efficient endogenous pain inhibitory capacity compared with men. Whether interventions that decrease pain sensitivity and enhance pain inhibition in women ultimately improve their clinical pain outcomes is an area of research that deserves additional attention in the future. PMID:26170713
Pain modulatory phenotypes differentiate subgroups with different clinical and experimental pain sensitivity.
Vaegter, Henrik B; Graven-Nielsen, Thomas
Pain biomarkers are warranted for individualized pain management. Based on different pain modulatory phenotypes, the objectives of this study were to explore the existence of subgroups within patients with nonmalignant chronic pain and to investigate differences in clinical pain and pain hypersensitivity between subgroups. Cuff algometry was performed on lower legs in 400 patients with chronic pain to assess pressure pain threshold, pressure pain tolerance, temporal summation of pain (TSP: increase in pain scores to 10 repeated stimulations), and conditioned pain modulation (CPM: increase in cuff pressure pain threshold during cuff pain conditioning on the contralateral leg). Heat detection and heat pain thresholds at clinical painful and nonpainful body areas were assessed. Based on TSP and CPM, 4 distinct groups were formed: group 1 (n = 85) had impaired CPM and facilitated TSP; group 2 (n = 148) had impaired CPM and normal TSP; group 3 (n = 45) had normal CPM and facilitated TSP; and group 4 (n = 122) had normal CPM and normal TSP. Group 1 showed more pain regions than the other 3 groups (P < 0.001), indicating that impaired CPM and facilitated TSP play an important role in widespread pain. Groups 1 and 2 compared with group 4 had lower heat pain threshold at nonpainful areas and lower cuff pressure pain tolerance (P < 0.02), indicating that CPM plays a role for widespread hyperalgesia. Moreover, group 1 demonstrated higher clinical pain scores than group 4 (P < 0.05). Although not different between subgroups, patients were profiled on demographics, disability, pain catastrophizing, and fear of movement. Future research should investigate interventions tailored towards these subgroups.
Effects of a Pain Catastrophizing Induction on Sensory Testing in Women with Chronic Low Back Pain: A Pilot Study
Sturgeon, John A.; Johnson, Kevin A.
Pain catastrophizing, a pattern of negative cognitive-emotional responses to actual or anticipated pain, maintains chronic pain and undermines response to treatments. Currently, precisely how pain catastrophizing influences pain processing is not well understood. In experimental settings, pain catastrophizing has been associated with amplified pain processing. This study sought to clarify pain processing mechanisms via experimental induction of pain catastrophizing. Forty women with chronic low back pain were assigned in blocks to an experimental condition, either a psychologist-led 10-minute pain catastrophizing induction or a control (10-minute rest period). All participants underwent a baseline round of several quantitative sensory testing (QST) tasks, followed by the pain catastrophizing induction or the rest period, and then a second round of the same QST tasks. The catastrophizing induction appeared to increase state pain catastrophizing levels. Changes in QST pain were detected for two of the QST tasks administered, weighted pin pain and mechanical allodynia. Although there is a need to replicate our preliminary results with a larger sample, study findings suggest a potential relationship between induced pain catastrophizing and central sensitization of pain. Clarification of the mechanisms through which catastrophizing affects pain modulatory systems may yield useful clinical insights into the treatment of chronic pain. PMID:28348505
The role of experimentally-induced subacromial pain on shoulder strength and throwing accuracy.
Wassinger, Craig A; Sole, Gisela; Osborne, Hamish
Shoulder injuries often comprise two separate yet related components, structural tissue damage and pain. The role of each of these components on shoulder function is difficult to ascertain. Experimental pain models allow the assessment of consequences of localized pain when applied to healthy individuals. By understanding the role of pain on shoulder function, clinicians will be able to more efficiently assess and treat shoulder injuries. The objective of the study was to evaluate the role of experimentally-induced sub-acromial pain on shoulder isokinetic rotational strength and throwing accuracy. This was a block counterbalanced, crossover, repeated measures study design utilizing 20 individuals without self-reported shoulder or cervical pathology. Shoulder function was measured with and without experimental pain injection (2 mL of 5% hypertonic saline) in the sub-acromial space. Functional tasks consisted of shoulder rotational strength utilizing isokinetic testing and throwing accuracy via the functional throwing performance index. The hypertonic saline induced moderate pain levels in all participants (4.3-5.1/10). Normalized shoulder internal (t = 3.76, p = 0.001) and external (t = 3.12, p = 0.006) rotation strength were both diminished in the painful condition compared to the pain free condition. Throwing accuracy was also reduced while the participants experienced pain (t = 3.99, p = 0.001). Moderate levels of experimental shoulder pain were sufficient to negatively influence shoulder strength and throwing accuracy in participants without shoulder pathology.
Gender, variation in opioid receptor genes and sensitivity to experimental pain
Background Pain tolerance is subject to considerable inter-individual variation, which may be influenced by a number of genetic and non-genetic factors. The mu, delta and kappa opioid receptors play a role in pain perception and are thought to mediate different pain modalities. The aim of this study was to explore associations between pain thresholds and gender and genetic variants in the three opioid receptor genes (OPRM, OPRD and OPRK). Experimental multi-modal pain data from previously published studies carried out in healthy Caucasian volunteers were used in order to limit the number of confounders to the study outcome. Data on thermal skin pain (n=36), muscle pressure pain (n=31) and mechanical visceral pain (n=50)) tolerance thresholds were included. Results Nineteen genetic polymorphisms were included in linear regression modeling. Males were found to tolerate higher thermal and muscle pressure pain than females (p=0.003 and 0.02). Thirty four percent of variability in thermal skin pain was accounted for by a model consisting of OPRK rs6473799 and gender. This finding was just outside significance when correction for multiple testing was applied. Variability in muscle pressure pain tolerance was associated with OPRK rs7016778 and rs7824175. These SNPs accounted for 43% of variability in muscle pressure pain sensitivity and these findings remained significant after adjustment for multiple testing. No association was found with mechanical visceral pain. Conclusion This is a preliminary and hypothesis generating study due to the relatively small study size. However, significant association between the opioid receptor genes and experimental pain sensitivity supports the influence of genetic variability in pain perception. These findings may be used to generate hypotheses for testing in larger clinical trials of patients with painful conditions. PMID:23570317
Long-Term Effects of Interprofessional Biopsychosocial Rehabilitation for Adults with Chronic Non-Specific Low Back Pain: A Multicentre, Quasi-Experimental Study
Semrau, Jana; Hentschke, Christian; Buchmann, Jana; Meng, Karin; Vogel, Heiner; Faller, Hermann; Bork, Hartmut; Pfeifer, Klaus
Background Improvement of the long-term effectiveness of multidisciplinary ortho-paedic rehabilitation (MOR) in the management of chronic non-specific low back pain (CLBP) remains a central issue for health care in Germany. We developed an interprofessional and interdisciplinary, biopsychosocial rehabilitation concept named "PASTOR" to promote self-management in adults with CLBP and compared its effectiveness with the current model of MOR. Methods A multicentre quasi-experimental study with three measurement time points was implemented. 680 adults aged 18 to 65 with CLBP were assed for eligibil-ity in three inpatient rehabilitation centres in Germany. At first the effects of the MOR, with a total extent of 48 hours (control group), were assessed. Thereafter, PASTOR was implemented and evaluated in the same centres (intervention group). It consisted of six interprofessional modules, which were provided on 12 days in fixed groups, with a total extent of 48 hours. Participants were assessed with self-report measures at baseline, discharge, and 12 months for functional ability (primary outcome) using the Hannover Functional Ability Questionnaire (FFbH-R) and vari-ous secondary outcomes (e.g. pain, health status, physical activity, pain coping, pain-related cognitions). Results In total 536 participants were consecutively assigned to PASTOR (n=266) or MOR (n=270). At 12 months, complete data of 368 participants was available. The adjusted between-group difference in the FFbH-R at 12 months was 6.58 (95% CI 3.38 to 9.78) using complete data and 3.56 (95% CI 0.45 to 6.67) using available da-ta, corresponding to significant small-to-medium effect sizes of d=0.42 (p<0.001) and d=0.10 (p=0.025) in favour of PASTOR. Further improvements in secondary out-comes were also observed in favour of PASTOR. Conclusion The interprofessional and interdisciplinary, biopsychosocial rehabilita-tion program PASTOR shows some improvements of the long-term effectiveness of inpatient
Experimental neck muscle pain impairs standing balance in humans.
Vuillerme, Nicolas; Pinsault, Nicolas
Impaired postural control has been reported in patients with chronic neck pain of both traumatic and non-traumatic etiologies, but whether painful stimulation of neck muscle per se can affect balance control during quiet standing in humans remains unclear. The purpose of the present experiment was thus to investigate the effect of experimental neck muscle pain on standing balance in young healthy adults. To achieve this goal, 16 male university students were asked to stand upright as still as possible on a force platform with their eyes closed in two conditions of No pain and Pain of the neck muscles elicited by experimental painful electrical stimulation. Postural control and postural performance were assessed by the displacements of the center of foot pressure (CoP) and of the center of mass (CoM), respectively. The results showed increased CoP and CoM displacements variance, range, mean velocity, and mean and median frequencies in the Pain relative to the No pain condition. The present findings emphasize the destabilizing effect of experimental neck muscle pain per se, and more largely stress the importance of intact neck neuromuscular function on standing balance.
Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats.
Long, Hu; Liao, Lina; Gao, Meiya; Ma, Wenqiang; Zhou, Yang; Jian, Fan; Wang, Yan; Lai, Wenli
Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals.
Sex, Gender, and Pain: A Review of Recent Clinical and Experimental Findings
Fillingim, Roger B.; King, Christopher D.; Ribeiro-Dasilva, Margarete C.; Rahim-Williams, Bridgett; Riley, Joseph L.
Sex-related influences on pain and analgesia have become a topic of tremendous scientific and clinical interest, especially in the last 10 to 15 years. Members of our research group published reviews of this literature more than a decade ago, and the intervening time period has witnessed robust growth in research regarding sex, gender, and pain. Therefore, it seems timely to revisit this literature. Abundant evidence from recent epidemiologic studies clearly demonstrates that women are at substantially greater risk for many clinical pain conditions, and there is some suggestion that postoperative and procedural pain may be more severe among women than men. Consistent with our previous reviews, current human findings regarding sex differences in experimental pain indicate greater pain sensitivity among females compared with males for most pain modalities, including more recently implemented clinically relevant pain models such as temporal summation of pain and intramuscular injection of algesic substances. The evidence regarding sex differences in laboratory measures of endogenous pain modulation is mixed, as are findings from studies using functional brain imaging to ascertain sex differences in pain-related cerebral activation. Also inconsistent are findings regarding sex differences in responses to pharmacologic and non-pharmacologic pain treatments. The article concludes with a discussion of potential biopsychosocial mechanisms that may underlie sex differences in pain, and considerations for future research are discussed. Perspective This article reviews the recent literature regarding sex, gender, and pain. The growing body of evidence that has accumulated in the past 10 to 15 years continues to indicate substantial sex differences in clinical and experimental pain responses, and some evidence suggests that pain treatment responses may differ for women versus men. PMID:19411059
A novel modelling and experimental technique to predict and measure tissue temperature during CO2 laser stimuli for human pain studies.
Al-Saadi, Mohammed Hamed; Nadeau, V; Dickinson, M R
Laser nerve stimulation is now accepted as one of the preferred methods for applying painful stimuli to human skin during pain studies. One of the main concerns, however, is thermal damage to the skin. We present recent work based on using a CO2 laser with a remote infrared (IR) temperature sensor as a feedback system. A model for predicting the subcutaneous skin temperature derived from the signal from the IR detector allows us to accurately predict the laser parameters, thus maintaining an optimum pain stimulus whilst avoiding dangerous temperature levels, which could result in thermal damage. Another aim is to relate the modelling of the CO2 fibre laser interaction to the pain response and compare these results with practical measurements of the pain threshold for various stimulus parameters. The system will also allow us to maintain a constant skin temperature during the stimulus. Another aim of the experiments underway is to review the psychophysics for pain in human subjects, permitting an investigation of the relationship between temperature and perceived pain.
Effect of experimental chewing on masticatory muscle pain onset
CONTI, Paulo César Rodrigues; SILVA, Rafael dos Santos; de ARAUJO, Carlos dos Reis Pereira; ROSSETI, Leylha Maria N.; YASSUDA, Shigueharu; da SILVA, Renato Oliveira Ferreira; PEGORARO, Luiz Fernando
Objectives To evaluate the effect of a chewing exercise on pain intensity and pressurepain threshold in patients with myofascial pain. Methods Twenty-nine consecutive women diagnosed with myofascial pain (MFP) according to the Research Diagnostic Criteria comprised the experimental group and 15 healthy age-matched female were used as controls. Subjects were asked to chew a gum stick for 9 min and to stay at rest for another 9 min afterwards. Pain intensity was rated on a visual analog scale (VAS) every 3 min. At 0, 9 and 18 min, the pressure-pain threshold (PPT) was measured bilaterally on the masseter and the anterior, medium, and posterior temporalis muscles. Results Patients with myofascial pain reported increase (76%) and no change (24%) on the pain intensity measured with the VAS. A reduction of the PPT at all muscular sites after the exercise and a non-significant recovery after rest were also observed. Conclusion The following conclusions can be drawn: 1. there are at least two subtypes of patients with myofascial pain that respond differently to experimental chewing; 2. the chewing protocol had an adequate discriminative ability in distinguishing patients with myofascial pain from healthy controls. PMID:21437467
Sex differences in parent and child pain ratings during an experimental child pain task.
Moon, E C; Chambers, C T; Larochette, Anne-Claire; Hayton, K; Craig, K D; McGrath, P J
Research in the field of pediatric pain has largely ignored the role of fathers in their children's pain experiences. The first objective of the present study was to examine the effect of the presence of mothers versus fathers on children's subjective ratings, facial expressions and physiological responses to acute pain. The second objective was to examine whether child and parent sex influence parents' proxy ratings of their children's pain. The final objective was to compare levels of agreement between mothers' and fathers' assessments of their children's pain. Participants included 73 children (37 boys, 36 girls), four to 12 years of age, along with 32 fathers and 41 mothers. Children undertook the cold pressor pain task while observed by one of their parents. During the task, the children's heart rates and facial expressions were recorded. Children provided self-reports and parents provided proxy reports of child pain intensity using the seven-point Faces Pain Scale. Neither child nor parent sex had a significant impact on children's subjective reports, facial expressions or heart rates in response to acute pain. Fathers gave their sons higher pain ratings than their daughters, whereas mothers' ratings of their sons' and daughters' pain did not differ. Kappa statistics and t tests revealed that fathers tended to be more accurate judges of their children's pain than mothers. Overall, this research highlights the importance of examining both parent and child sex differences in pediatric pain research.
Adult attachment and reports of pain in experimentally-induced pain.
Andrews, Nicole Emma; Meredith, Pamela Joy; Strong, Jenny
Attachment theory has been proposed as a framework for understanding the development of chronic pain, with evidence supporting the overrepresentation of insecure attachment styles in chronic pain populations and links between insecure attachment and factors known to impact one's ability to cope with pain. The present study sought to extend two earlier studies exploring the relationships between adult attachment and communication of an acute pain experience, in anticipation of providing insight into individual differences in vulnerability in development of chronic pain. It was hypothesised that: (a) fearful attachment would be associated with perceptions of the pain as less intense, and (b) anxious attachment would be associated with lower pain thresholds. A convenience sample of 82 healthy adults completed self-report measures of attachment, neuroticism, and negative affect prior to taking part in a coldpressor pain inducement task. Results demonstrated that fearful attachment was associated with lower levels of pain intensity throughout the coldpressor task. In addition, dismissing attachment was also associated with less intense pain, as well as increased coldpressor endurance (tolerance) in the presence of a known assessor. These associations were retained after controlling for measures of neuroticism, negative affect, age, and social desirability. The results of this study are consistent with the proposition that fearful and dismissing individuals tend to mask their underlying distress caused by the pain experience, potentially leading to difficulties coping with pain over time.
Central Pain Processing in Early-Stage Parkinson's Disease: A Laser Pain fMRI Study
Petschow, Christine; Scheef, Lukas; Paus, Sebastian; Zimmermann, Nadine; Schild, Hans H.; Klockgether, Thomas; Boecker, Henning
Background & Objective Pain is a common non-motor symptom in Parkinson's disease. As dopaminergic dysfunction is suggested to affect intrinsic nociceptive processing, this study was designed to characterize laser-induced pain processing in early-stage Parkinson's disease patients in the dopaminergic OFF state, using a multimodal experimental approach at behavioral, autonomic, imaging levels. Methods 13 right-handed early-stage Parkinson's disease patients without cognitive or sensory impairment were investigated OFF medication, along with 13 age-matched healthy control subjects. Measurements included warmth perception thresholds, heat pain thresholds, and central pain processing with event-related functional magnetic resonance imaging (erfMRI) during laser-induced pain stimulation at lower (E = 440 mJ) and higher (E = 640 mJ) target energies. Additionally, electrodermal activity was characterized during delivery of 60 randomized pain stimuli ranging from 440 mJ to 640 mJ, along with evaluation of subjective pain ratings on a visual analogue scale. Results No significant differences in warmth perception thresholds, heat pain thresholds, electrodermal activity and subjective pain ratings were found between Parkinson's disease patients and controls, and erfMRI revealed a generally comparable activation pattern induced by laser-pain stimuli in brain areas belonging to the central pain matrix. However, relatively reduced deactivation was found in Parkinson's disease patients in posterior regions of the default mode network, notably the precuneus and the posterior cingulate cortex. Conclusion Our data during pain processing extend previous findings suggesting default mode network dysfunction in Parkinson's disease. On the other hand, they argue against a genuine pain-specific processing abnormality in early-stage Parkinson's disease. Future studies are now required using similar multimodal experimental designs to examine pain processing in more advanced
The relationship of the audible pop to hypoalgesia associated with high velocity, low amplitude thrust manipulation: A secondary analysis of an experimental study in pain free participants
Bishop, Mark D; Robinson, Michael E; George, Steven Z
Objective High velocity, low amplitude (HVLA) manipulation is an effective treatment for low back pain (LBP); however, the corresponding mechanisms are undetermined. Hypoalgesia is associated with HVLA manipulation and suggests specific mechanisms of action. An audible pop (AP) is also associated with HVLA manipulation; however, the influence of the AP on the hypoalgesia associated with HVLA manipulation is not established. The purpose of the current study was to observe the influence of the AP on hypoalgesia associated with HVLA manipulation. Methods The current study represents a secondary analysis of 40 participants. All participants underwent thermal pain sensitivity testing to their leg and low back using protocols specific to Aδ fiber mediated pain and temporal summation. Next, participants received HVLA manipulation to their low back and the examiner recorded whether or not an AP was perceived. Finally, participants underwent immediate follow up thermal pain sensitivity testing using the same protocols. Separate repeated measure ANOVAs were used to observe changes in pain sensitivity prior to and immediately following HVLA manipulation. Results Hypoalgesia of Aδ fiber mediated pain was observed in the low back following HVLA (p< 0.05) and this was independent of whether an AP was perceived (p> 0.05). Hypoalgesia of temporal summation was observed in the lower extremity following HVLA (p< 0.05) and this was independent of whether an AP was perceived (p= 0.08). However, a moderate effect size for temporal summation was observed favoring participants in whom an AP was perceived. Conclusion The current study suggests hypoalgesia is associated with HVLA manipulation and occurs independently of a perceived AP. Inhibition of lower extremity temporal summation may be larger in individuals in whom an AP is perceived, but further study is necessary to confirm this finding. PMID:20170777
Effects of coping statements on experimental pain in chronic pain patients.
Roditi, Daniela; Robinson, Michael E; Litwins, Nola
The present study measured the effects of catastrophizing self-statements and positive coping self-statements on cold pressor-induced pain. Participants were 58 adult chronic pain patients with current facial pain. It was hypothesized that catastrophizing would lead to a decrease in pain endurance whereas positive coping would lead to an increase in pain endurance. It was also hypothesized that catastrophizing would lead to an increase in peak pain intensity whereas positive coping would lead to a decrease in peak pain intensity. At pretest, participants submerged their nondominant hand in the cold pressor. Pain sensitivity ranges (PSR) were subsequently determined by calculating the difference between tolerance and threshold times. Ratings of peak pain intensity were measured using a pressure sensitive bladder/transducer. Participants underwent random assignment to either a catastrophizing group or a positive coping self-statement group. ANCOVA results revealed that on average, participants employing catastrophizing statements as a coping strategy experienced significantly lower PSR (M = 35.53, SD = 39.71) compared to participants employing positive coping self-statements (M = 73.70, SD = 86.14) when controlling for pretest PSR. Group assignment had no significant influence on peak pain intensity ratings. Thus, our results reveal that manipulation of coping causes changes in pain endurance.
Asians differ from non-Hispanic Whites in experimental pain sensitivity.
Rowell, Lauren N; Mechlin, Beth; Ji, Ellen; Addamo, Michael; Girdler, Susan S
This study examined differences between Asians and non-Hispanic Whites (Whites) in pain sensitivity, and its relationship to mean arterial pressure (MAP) and heart rate (HR). In 30 Whites (50% female) and 30 Asians (50% female), experimental pain sensitivity was assessed with a hand cold pressor task, yielding measures of pain threshold, tolerance, intensity, and unpleasantness. Mean arterial pressure and HR measurements taken at rest and in response to speech stress were assessed. Perceived stress, anxiety, perfectionism, parental criticism, parental expectations and depressive symptoms were also measured. The results indicated that for the cold pain test, Asians demonstrated significantly lower pain threshold and tolerance levels than Whites. Although no ethnic differences were seen for MAP or HR responses to stress, for Whites higher stress MAP levels were correlated with reduced pain sensitivity, while for Asians higher baseline and stress HR levels were correlated with reduced pain sensitivity. Asians reported higher parental expectations and greater parental criticism than Whites. For Asians only, higher levels of perfectionism were related to more depressive symptoms, anxiety and perceived stress. These results indicate that Asian Americans are more sensitive to experimental pain than Whites and suggest ethnic differences in endogenous pain regulatory mechanisms (e.g. MAP and HR). The results may also have implications for understanding ethnic differences in clinical pain.
Is experimentally induced pain associated with socioeconomic status? Do poor people hurt more?
Miljković, Ana; Stipčić, Ana; Braš, Marijana; Đorđević, Veljko; Brajković, Lovorka; Hayward, Caroline; Pavić, Arsen; Kolčić, Ivana; Polašek, Ozren
Background The association of pain and socioeconomic status is widely reported, yet much less clearly understood. The aim of this study was to investigate the association of experimentally induced pain threshold and tolerance with socioeconomic status. Material/Methods The study sample consisted of 319 adult subjects from the population of the island of Vis, Croatia, which was previously shown to have a high level of social homogeneity. A manual dolorimeter was used to measure mechanical pressure pain threshold (least stimulus intensity) and pain tolerance (maximum tolerance stimulus intensity) on both hands. Pain tolerance interval was defined as the difference between pain tolerance and threshold. Years of schooling and material status were used as socioeconomic estimates. Results Both of the socioeconomic estimates were significantly correlated with pain threshold, tolerance, and tolerance interval (P<0.001). The mixed modeling analysis, controlled for the effects of age, gender, and 4 psychological variables, indicated that education was not a significant predictor in any of the 3 models. However, lower material status was significantly associated with lower pain tolerance (P=0.038) and narrower pain tolerance interval (P=0.032), but not with pain threshold (P=0.506). The overall percentages of explained variance were lower in the tolerance interval model (20.2%) than in pain tolerance (23.1%) and threshold (33.1%), suggesting the increasing share of other confounding variables in pain tolerance and even more so in tolerance interval model. Conclusions These results suggest a significant association between experimentally induced pain tolerance and tolerance interval with material status, suggesting that poor people indeed do hurt more. PMID:25029965
IL17 Mediates Pelvic Pain in Experimental Autoimmune Prostatitis (EAP)
Murphy, Stephen F.; Schaeffer, Anthony J.; Done, Joseph; Wong, Larry; Bell-Cohn, Ashlee; Roman, Kenny; Cashy, John; Ohlhausen, Michelle; Thumbikat, Praveen
Chronic pelvic pain syndrome (CPPS) is the most common form of prostatitis, accounting for 90–95% of all diagnoses. It is a complex multi-symptom syndrome with unknown etiology and limited effective treatments. Previous investigations highlight roles for inflammatory mediators in disease progression by correlating levels of cytokines and chemokines with patient reported symptom scores. It is hypothesized that alteration of adaptive immune mechanisms results in autoimmunity and subsequent development of pain. Mouse models of CPPS have been developed to delineate these immune mechanisms driving pain in humans. Using the experimental autoimmune prostatitis (EAP) in C57BL/6 mice model of CPPS we examined the role of CD4+T-cell subsets in the development and maintenance of prostate pain, by tactile allodynia behavioral testing and flow cytometry. In tandem with increased CD4+IL17A+ T-cells upon EAP induction, prophylactic treatment with an anti-IL17 antibody one-day prior to EAP induction prevented the onset of pelvic pain. Therapeutic blockade of IL17 did not reverse pain symptoms indicating that IL17 is essential for development but not maintenance of chronic pain in EAP. Furthermore we identified a cytokine, IL7, to be associated with increased symptom severity in CPPS patients and is increased in patient prostatic secretions and the prostates of EAP mice. IL7 is fundamental to development of IL17 producing cells and plays a role in maturation of auto-reactive T-cells, it is also associated with autoimmune disorders including multiple sclerosis and type-1 diabetes. More recently a growing body of research has pointed to IL17's role in development of neuropathic and chronic pain. This report presents novel data on the role of CD4+IL17+ T-cells in development and maintenance of pain in EAP and CPPS. PMID:25933188
Analgesics as Reinforcers with Chronic Pain: Evidence from Operant Studies
Ewan, Eric E.; Martin, Thomas J.
Previously preclinical pain research has focused on simple behavioral endpoints to assess the efficacy of analgesics in acute and chronic pain models, primarily reflexive withdrawal from an applied mechanical or thermal stimulus. However recent research has been aimed at investigating other behavioral states in the presence of pain, including spontaneous, non-elicited pain. One approach is to investigate the reinforcing effects of analgesics in animals with experimental pain, which should serve as reinforcers by virtue of their ability to alleviate the relevant subjective states induced by pain. The gold standard for assessing drug reinforcement is generally accepted to be drug self-administration, and this review highlights the ability of drugs to serve as reinforcers in animals with experimental neuropathic pain, and the extent to which this behavior is altered in chronic pain states. Additionally, intracranial self-stimulation is an operant procedure that has been used extensively to study drug reinforcement mechanisms and the manner in which neuropathic pain alters the ability of drugs to serve as reinforcers in this paradigm will also be discussed. Drug self-administration and intracranial self-stimulation have promise as tools to investigate behavioral effects of analgesics in animals with chronic pain, particularly regarding the mechanisms through which these drugs motivate consumption in a chronic pain state. PMID:23973302
Analgesics as reinforcers with chronic pain: Evidence from operant studies.
Ewan, Eric E; Martin, Thomas J
Previously preclinical pain research has focused on simple behavioral endpoints to assess the efficacy of analgesics in acute and chronic pain models, primarily reflexive withdrawal from an applied mechanical or thermal stimulus. However recent research has been aimed at investigating other behavioral states in the presence of pain, including spontaneous, non-elicited pain. One approach is to investigate the reinforcing effects of analgesics in animals with experimental pain, which should serve as reinforcers by virtue of their ability to alleviate the relevant subjective states induced by pain. The gold standard for assessing drug reinforcement is generally accepted to be drug self-administration, and this review highlights the ability of drugs to serve as reinforcers in animals with experimental neuropathic pain, and the extent to which this behavior is altered in chronic pain states. Additionally, intracranial self-stimulation is an operant procedure that has been used extensively to study drug reinforcement mechanisms and the manner in which neuropathic pain alters the ability of drugs to serve as reinforcers in this paradigm will also be discussed. Drug self-administration and intracranial self-stimulation have promise as tools to investigate behavioral effects of analgesics in animals with chronic pain, particularly regarding the mechanisms through which these drugs motivate consumption in a chronic pain state.
Experimenter Effects on Pain Reporting in Women Vary across the Menstrual Cycle
Vigil, Jacob M.; DiDomenico, Jared; Strenth, Chance; Coulombe, Patrick; Kruger, Eric; Mueller, Andrea A.; Guevara Beltran, Diego; Adams, Ian
Background. Separate lines of research have shown that menstrual cycling and contextual factors such as the gender of research personnel influence experimental pain reporting. Objectives. This study examines how brief, procedural interactions with female and male experimenters can affect experimentally reported pain (cold pressor task, CPT) across the menstrual cycle. Methods. Based on the menstrual calendars 94 naturally cycling women and 38 women using hormonal contraceptives (Mage = 19.83, SD = 3.09) were assigned to low and high fertility groups. This assignment was based on estimates of their probability of conception given their current cycle day. Experimenters (12 males, 7 females) engaged in minimal procedural interactions with participants before the CPT was performed in solitude. Results. Naturally cycling women in the high fertility group showed significantly higher pain tolerance (81 sec, d = .79) following interactions with a male but not a female experimenter. Differences were not found for women in the low fertility or contraceptive groups. Discussion. The findings illustrate that menstrual functioning moderates the effect that experimenter gender has on pain reporting in women. Conclusion. These findings have implications for standardizing pain measurement protocols and understanding how basic biopsychosocial mechanisms (e.g., person-perception systems) can modulate pain experiences. PMID:25892990
Clinical pharmacology of analgesics assessed with human experimental pain models: bridging basic and clinical research
Oertel, Bruno Georg; Lötsch, Jörn
The medical impact of pain is such that much effort is being applied to develop novel analgesic drugs directed towards new targets and to investigate the analgesic efficacy of known drugs. Ongoing research requires cost-saving tools to translate basic science knowledge into clinically effective analgesic compounds. In this review we have re-examined the prediction of clinical analgesia by human experimental pain models as a basis for model selection in phase I studies. The overall prediction of analgesic efficacy or failure of a drug correlated well between experimental and clinical settings. However, correct model selection requires more detailed information about which model predicts a particular clinical pain condition. We hypothesized that if an analgesic drug was effective in an experimental pain model and also a specific clinical pain condition, then that model might be predictive for that particular condition and should be selected for development as an analgesic for that condition. The validity of the prediction increases with an increase in the numbers of analgesic drug classes for which this agreement was shown. From available evidence, only five clinical pain conditions were correctly predicted by seven different pain models for at least three different drugs. Most of these models combine a sensitization method. The analysis also identified several models with low impact with respect to their clinical translation. Thus, the presently identified agreements and non-agreements between analgesic effects on experimental and on clinical pain may serve as a solid basis to identify complex sets of human pain models that bridge basic science with clinical pain research. PMID:23082949
Effects of restricted environmental stimulation: enhancement of hypnotizability for experimental and chronic pain control.
Barabasz, A F; Barabasz, M
Enhancement of hypnotizability and pain tolerance has been demonstrated using restricted environmental stimulation therapy (REST) with university students as Ss (A. F. Barabasz, 1982). The purpose of the present study was to determine whether or not similar results could be obtained with chronic pain patients. Ss consisted of outpatients in treatment for conditions in which pain is prominent who also demonstrated low hypnotizability after repeated hypnosis plateau sessions. 2 groups of Ss were exposed to REST. Situational demand characteristics (Orne, 1962) favored an increase in hypnotizability for REST Group 1 (high demand). REST Group 2 (low demand) was exposed to situational demand characteristics designed to disguise the experimental hypothesis. 2 groups of control Ss were exposed to the same alternative demand characteristic manipulations as the experimental groups, but environmental stimulation was maintained. The Stanford Hypnotic Susceptibility Scale, Form C (SHSS:C) of Weitzenhoffer and E. R. Hilgard (1962), including a posthypnotic suggestion for an anesthetic reaction, and an ischemic pain test were administered prior to treatment and again immediately following treatment. After 6 hours of REST, significant increases in SHSS:C scores were found for high-demand and low-demand experimental Ss, as well as for high-demand control Ss. No such increase was found for low-demand controls. Significant decreases in pain scores were found for both high- and low-demand experimental groups. No significant pain score decreases were found for either control group, suggesting a relatively weak effect of demand characteristics. An independent postexperimental inquiry suggested all Ss believed they received active treatments. The inquiry, conducted 10-15 days after the experiment, also revealed a majority of experimental Ss were using hypnosis on a daily basis to reduce pain with a substantial decrease in pain medication. Only 2 control Ss (highest in hypnotizability
Sex differences in how social networks and relationship quality influence experimental pain sensitivity.
Vigil, Jacob M; Rowell, Lauren N; Chouteau, Simone; Chavez, Alexandre; Jaramillo, Elisa; Neal, Michael; Waid, David
This is the first study to examine how both structural and functional components of individuals' social networks may moderate the association between biological sex and experimental pain sensitivity. One hundred and fifty-two healthy adults (mean age = 22yrs., 53% males) were measured for cold pressor task (CPT) pain sensitivity (i.e., intensity ratings) and core aspects of social networks (e.g., proportion of friends vs. family, affection, affirmation, and aid). Results showed consistent sex differences in how social network structures and intimate relationship functioning modulated pain sensitivity. Females showed higher pain sensitivity when their social networks consisted of a higher proportion of intimate types of relationship partners (e.g., kin vs. non kin), when they had known their network partners for a longer period of time, and when they reported higher levels of logistical support from their significant other (e.g., romantic partner). Conversely, males showed distinct patterns in the opposite direction, including an association between higher levels of logistical support from one's significant other and lower CPT pain intensity. These findings show for the first time that the direction of sex differences in exogenous pain sensitivity is likely dependent on fundamental components of the individual's social environment. The utility of a social-signaling perspective of pain behaviors for examining, comparing, and interpreting individual and group differences in experimental and clinical pain reports is discussed.
Gender role affects experimental pain responses: a systematic review with meta-analysis.
Alabas, O A; Tashani, O A; Tabasam, G; Johnson, M I
Gender role refers to the culturally and socially constructed meanings that describe how women and men should behave in certain situations according to feminine and masculine roles learned throughout life. The aim of this meta-analysis was to evaluate the relationship between gender role and experimental pain responses in healthy human participants. We searched computerized databases for studies published between January 1950 and May 2011 that had measured gender role in healthy human adults and pain response to noxious stimuli. Studies were entered into a meta-analysis if they calculated a correlation coefficient (r) for gender role and experimental pain. Searches yielded 4465 'hits' and 13 studies were eligible for review. Sample sizes were 67-235 participants and the proportion of female participants was 45-67%. Eight types of gender role instrument were used. Meta-analysis of six studies (406 men and 539 women) found a significant positive correlation between masculine and feminine personality traits and pain threshold and tolerance, with a small effect size (r = 0.17, p = 0.01). Meta-analysis of four studies (263 men and 297 women) found a significant negative correlation between gender stereotypes specific to pain and pain threshold and tolerance, with a moderate effect size (r = -0.41, p < 0.001). In conclusion, individuals who considered themselves more masculine and less sensitive to pain than the typical man showed higher pain thresholds and tolerances. Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales.
A randomized, double-blind, positive-controlled, 3-way cross-over human experimental pain study of a TRPV1 antagonist (V116517) in healthy volunteers and comparison with preclinical profile.
Arendt-Nielsen, Lars; Harris, Steve; Whiteside, Garth T; Hummel, Michele; Knappenberger, Terri; O'Keefe, Sarah; Kapil, Ram; Kyle, Don
This experimental, translational, experimental pain, single-center, randomized, double-blind, single-dose, 3-treatment, 3-period cross-over proof-of-concept volunteer trial studied the efficacy of a novel TRPV1 antagonist (V116517) on capsaicin- and UV-B-induced hyperalgesia. Heat and pressure pain thresholds, von Frey stimulus-response functions, and neurogenic inflammation were assessed together with safety. Each treatment period was 4 days. The 3 single oral treatments were 300 mg V116517, 400 mg celecoxib (a COX-2 inhibitor), and placebo. The heat pain detection and tolerance thresholds were increased significantly (P < 0.0001) by V116517. Heat pain detection and tolerance thresholds showed significantly less capsaicin hyperalgesia after V116517 (P = 0.004 and P < 0.0001, respectively). Celecoxib reduced UV-B-provoked pressure pain sensitization (P = 0.01). Laser Doppler flowmetry and erythema index after UV-B were significantly (P < 0.0001) reduced by celecoxib. Stimulus-response function in capsaicin-treated areas showed significant differences between both celecoxib and placebo and between V116517 and placebo. The body temperature showed no change, and no side effects were reported for any of the treatments. The TRPV1 antagonists and the COX-2 inhibitor showed different antihyperalgesic profiles indicating different clinical targets. In addition, the preclinical profile of V116517 in rat models of UV-B and capsaicin-induced hypersensitivity was compared with the human experimental data and overall demonstrated an alignment between 2 of the 3 end points tested. The TRPV1 antagonist showed a potent antihyperalgesic action without changing the body temperature but heat analgesia may be a potential safety issue.
Social comparison performance standards, threat, and tolerance for experimentally-induced pain.
Jackson, Todd; Phillips, Heath
Social modelling experiments have illustrated how upward social comparisons (i.e., observing pain tolerant role models) can facilitate tolerance relative to downward social comparison (i.e., observing pain intolerant alternatives). However, because clinical studies suggest that people prefer to make downward social comparisons with less fortunate others when they are threatened or overwhelmed with pain or illness, it seems plausible that upward social comparisons confer fewer benefits when pain is appraised as threatening. To address this issue, we assessed effects of verbally-presented upward and downward social comparison standards on tolerance for cold pressor pain among 124 Australian adults (44 men, 80 women) primed with either more or less threatening orienting information about task-related pain sensations. As predicted, participants exposed to the lower threat orienting prime and upward comparison performance standard were significantly more pain tolerant than peers in all other conditions. Conversely, the average tolerance time for participants presented with the higher threat orienting prime and upward comparison standard did not differ from that of either downward comparison group. The research highlighted powerful situational influences on tolerance for experimental pain and identified conditions under which verbally-presented upward social comparison standards may facilitate and hinder the capacity to bear pain.
Peripheral sensory neuron injury contributes to neuropathic pain in experimental autoimmune encephalomyelitis
Wang, I-Ching; Chung, Chen-Yen; Liao, Fang; Chen, Chih-Cheng; Lee, Cheng-Han
Multiple sclerosis (MS)-induced neuropathic pain deteriorates quality of life in patients but is often refractory to treatment. In experimental autoimmune encephalomyelitis (EAE), a rodent model of MS, animals develop neuropathy and inflammation-induced tissue acidosis, which suggests the involvement of acid-sensing ion channels (ASICs). Also, peripheral neuropathy is reported in MS patients. However, the involvement of the peripheral nervous system (PNS) in MS neuropathic pain remains elusive. This study investigated the contribution of ASICs and peripheral neuropathy in MS-induced neuropathic pain. Elicited pain levels were as high in Asic1a−/−, Asic2−/− and Asic3−/− mice as wild-type mice even though only Asic1a−/− mice showed reduced EAE disease severity, which indicates that pain in EAE was independent of disease severity. We thus adopted an EAE model without pertussis toxin (EAEnp) to restrain activated immunity in the periphery and evaluate the PNS contribution to pain. Both EAE and EAEnp mice showed similar pain behaviors and peripheral neuropathy in nerve fibers and DRG neurons. Moreover, pregabalin significantly reduced neuropathic pain in both EAE and EAEnp mice. Our findings highlight the essential role of the PNS in neuropathic pain in EAE and pave the way for future development of analgesics without side effects in the CNS. PMID:28181561
Evaluation of ketamine, nimodipine, gabapentin and imipramine in partial sciatic nerve transection model of neuropathic pain in rat: an experimental study.
Hota, D; Bansal, V; Pattanaik, S
The aim of this research is to study the effects of nimodipine, gabapentin, ketamine and imipramine in the partial sciatic nerve transection (PST) model of neuropathic pain in rats. PST was produced in young Wistar rats of either sex by partial destruction of the sciatic nerve. A decrease in the latency to paw withdrawal reaction on the hot plate was considered as development of neuropathy. The drugs were given daily from the third day of the procedure, and evaluation was done on days 7, 14, 21 and 28. There was a significant decrease (p < 0.05) in the paw withdrawal response in the nimodipine group from day 14 onward when compared with the control group. In the ketamine and imipramine group, this response was seen from day 21 onward. The effect persisted till the end of the study. There was no improvement in the gabapentin group. The results of our study show that nimodipine (dihydropyridine calcium channel blocker), ketamine (NMDA antagonist) and imipramine (tricyclic antidepressant) modulated hyperalgesia and allodynia in the PST model of neuropathy. Gabapentin (an alpha-2 delta calcium subunit blocker) did not show any effect in this model of neuropathy. The widespread use of gabapentin in various types of neuropathic pain thus needs to be reevaluated.
Space Adaptation Back Pain: A Retrospective Study
NASA Technical Reports Server (NTRS)
Kerstman, E. L.; Scheuring, R. A.; Barnes, M. G.; DeKorse, T. B.; Saile, L. G.
Back pain is frequently reported by astronauts during the early phase of space flight as they adapt to the microgravity environment. However, the epidemiology of space adaptation back pain has not been well defined. The purpose of this retrospective study was to develop a case definition of space adaptation back pain, determine the incidence of space adaptation back pain, and determine the effectiveness of available treatments. Medical records from the Mercury, Apollo, Apollo-Soyuz Test Project (ASTP), Skylab, Mir, International Space Station (ISS), and Shuttle programs were reviewed. All episodes of in-flight back pain that met the criteria for space adaptation back pain were recorded. Pain characteristics, including intensity, location, and duration of the pain were noted. The effectiveness of specific treatments also was recorded. The incidence of space adaptation back pain among astronauts was determined to be 53% (384/722). Most of the affected astronauts reported mild pain (85%). Moderate pain was reported by 11% of the affected astronauts and severe pain was reported by only 4% of the affected astronauts. The most effective treatments were fetal positioning (91% effective) and the use of analgesic medications (85% effective). This retrospective study aids in the development of a case definition of space adaptation back pain and examines the epidemiology of space adaptation back pain. Space adaptation back pain is usually mild and self-limited. However, there is a risk of functional impairment and mission impact in cases of moderate or severe pain that do not respond to currently available treatments. Therefore, the development of preventive measures and more effective treatments should be pursued.
Inflammation-induced pain sensitization in men and women: does sex matter in experimental endotoxemia?
Wegner, Alexander; Elsenbruch, Sigrid; Rebernik, Laura; Roderigo, Till; Engelbrecht, Elisa; Jäger, Marcus; Engler, Harald; Schedlowski, Manfred; Benson, Sven
A role of the innate immune system is increasingly recognized as a mechanism contributing to pain sensitization. Experimental administration of the bacterial endotoxin lipopolysaccharide (LPS) constitutes a model to study inflammation-induced pain sensitization, but all existing human evidence comes from male participants. We assessed visceral and musculoskeletal pain sensitivity after low-dose LPS administration in healthy men and women to test the hypothesis that women show greater LPS-induced hyperalgesia compared with men. In this randomized, double-blind, placebo-controlled crossover study, healthy men (n = 20) and healthy women using oral contraceptives (n = 20) received an intravenous injection of 0.4 ng/kg body weight LPS or placebo. Pain sensitivity was assessed with established visceral and musculoskeletal pain models (ie, rectal pain thresholds; pressure pain thresholds for different muscle groups), together with a heartbeat perception (interoceptive accuracy) task. Plasma cytokines (tumor necrosis factor-α and interleukin-6) were measured along with state anxiety at baseline and up to 6-hour postinjection. Lipopolysaccharide application led to significant increases in plasma cytokines and state anxiety and decreased interoceptive awareness in men and women (P < 0.001, condition effects), with more pronounced LPS-induced cytokine increases in women (P < 0.05, interaction effects). Although both rectal and pressure pain thresholds were significantly decreased in the LPS condition (all P < 0.05, condition effect), no sex differences in endotoxin-induced sensitization were observed. In summary, LPS-induced systemic immune activation leads to visceral and musculoskeletal hyperalgesia, irrespective of biological sex. These findings support the broad applicability of experimental endotoxin administration as a translational preclinical model of inflammation-induced pain sensitization in both sexes.
Adaptability to pain is associated with potency of local pain inhibition, but not conditioned pain modulation: a healthy human study.
Zheng, Zhen; Wang, Kelun; Yao, Dongyuan; Xue, Charlie C L; Arendt-Nielsen, Lars
This study investigated the relationship between pain sensitivity, adaptability, and potency of endogenous pain inhibition, including conditioned pain modulation (CPM) and local pain inhibition. Forty-one healthy volunteers (20 male, 21 female) received conditioning stimulation (CS) over 2 sessions in a random order: tonic heat pain (46 °C) on the right leg for 7 minutes and cold pressor pain (1 °C to 4 °C) on the left hand for 5 minutes. Participants rated the intensity of pain continuously using a 0 to 10 electronic visual analogue scale. The primary outcome measures were pressure pain thresholds (PPT) measured at the heterotopic and homotopic location to the CS sites before, during, and 20 minutes after CS. Two groups of participants, pain adaptive and pain nonadaptive, were identified based on their response to pain in the cold pressor test. Pain-adaptive participants showed a pain reduction between peak pain and pain at end of the test by at least 2 of 10 (n=16); whereas the pain-nonadaptive participants reported unchanged peak pain during 5-minute CS (n=25). Heterotopic PPTs during the CS did not differ between the 2 groups. However, increased homotopic PPTs measured 20 minutes after CS correlated with the amount of pain reduction during CS. These results suggest that individual sensitivity and adaptability to pain does not correlate with the potency of CPM. Adaptability to pain is associated with longer-lasting local pain inhibition.
Adult stem cell as new advanced therapy for experimental neuropathic pain treatment.
Franchi, Silvia; Castelli, Mara; Amodeo, Giada; Niada, Stefania; Ferrari, Daniela; Vescovi, Angelo; Brini, Anna Teresa; Panerai, Alberto Emilio; Sacerdote, Paola
Neuropathic pain (NP) is a highly invalidating disease resulting as consequence of a lesion or disease affecting the somatosensory system. All the pharmacological treatments today in use give a long lasting pain relief only in a limited percentage of patients before pain reappears making NP an incurable disease. New approaches are therefore needed and research is testing stem cell usage. Several papers have been written on experimental neuropathic pain treatment using stem cells of different origin and species to treat experimental NP. The original idea was based on the capacity of stem cell to offer a totipotent cellular source for replacing injured neural cells and for delivering trophic factors to lesion site; soon the researchers agreed that the capacity of stem cells to contrast NP was not dependent upon their regenerative effect but was mostly linked to a bidirectional interaction between the stem cell and damaged microenvironment resident cells. In this paper we review the preclinical studies produced in the last years assessing the effects induced by several stem cells in different models of neuropathic pain. The overall positive results obtained on pain remission by using stem cells that are safe, of easy isolation, and which may allow an autologous transplant in patients may be encouraging for moving from bench to bedside, although there are several issues that still need to be solved.
Suggestions to Reduce Clinical Fibromyalgia Pain and Experimentally Induced Pain Produce Parallel Effects on Perceived Pain but Divergent Functional MRI–Based Brain Activity
Derbyshire, Stuart W.G.; Whalley, Matthew G.; Seah, Stanley T.H.; Oakley, David A.
ABSTRACT Objective Hypnotic suggestion is an empirically validated form of pain control; however, the underlying mechanism remains unclear. Methods Thirteen fibromyalgia patients received suggestions to alter their clinical pain, and 15 healthy controls received suggestions to alter experimental heat pain. Suggestions were delivered before and after hypnotic induction with blood oxygen level–dependent (BOLD) activity measured concurrently. Results Across groups, suggestion produced substantial changes in pain report (main effect of suggestion, F2, 312 = 585.8; p < .0001), with marginally larger changes after induction (main effect of induction, F1, 312 = 3.6; p = .060). In patients, BOLD response increased with pain report in regions previously associated with pain, including thalamus and anterior cingulate cortex. In controls, BOLD response decreased with pain report. All changes were greater after induction. Region-of-interest analysis revealed largely linear patient responses with increasing pain report. Control responses, however, were higher after suggestion to increase or decrease pain from baseline. Conclusions Based on behavioral report alone, the mechanism of suggestion could be interpreted as largely similar regardless of the induction or type of pain experience. The functional magnetic resonance imaging data, however, demonstrated larger changes in brain activity after induction and a radically different pattern of brain activity for clinical pain compared with experimental pain. These findings imply that induction has an important effect on underlying neural activity mediating the effects of suggestion, and the mechanism of suggestion in patients altering clinical pain differs from that in controls altering experimental pain. Patient responses imply that suggestions altered pain experience via corresponding changes in pain-related brain regions, whereas control responses imply suggestion engaged cognitive control. PMID:27490850
Genetic predictors for acute experimental cold and heat pain sensitivity in humans
Kim, H; Mittal, D P; Iadarola, M J; Dionne, R A
Background The genetic contribution to pain sensitivity underlies a complex composite of parallel pain pathways, multiple mechanisms, and diverse inter‐individual pain experiences and expectations. Methods Variations for genes encoding receptors related to cold and heat sensation, such as transient receptor potential A subtype 1 (TRPA1), M subtype 8 (TRPM8), V subtype 1 (TRPV1), δ opioid receptor subtype 1 (OPRD1), catechol O‐methyltransferase (COMT), and fatty acid amide hydrolyase (FAAH), were investigated in four major ethnic populations. Results We defined 13 haplotype blocks in European Americans, seven blocks in African Americans, seven blocks in Hispanic subjects, and 11 blocks in Asian Americans. Further study in European American subjects found significant associations between short duration cold pain sensitivity and variations in TRPA1, COMT, and FAAH in a gender dependent manner. Our observations demonstrate that genetic variations in TRPA1, COMT, and FAAH contribute gender specifically to individual variations in short duration cold pain sensitivity in a European American cohort. Conclusions The effects of TRPA1 variations on experimental short duration heat pain sensitivity may contribute to inter‐individual variation in pain sensitivity in humans. PMID:16882734
Deciphering the Temporal Link between Pain and Sleep in a Heterogeneous Chronic Pain Patient Sample: A Multilevel Daily Process Study
Tang, Nicole K.Y.; Goodchild, Claire E.; Sanborn, Adam N.; Howard, Jonathan; Salkovskis, Paul M.
Objectives: Because insomnia is a common comorbidity of chronic pain, scientific and clinical interest in the relationship of pain and sleep has surged in recent years. Although experimental studies suggest a sleep-interfering property of pain and a pain-enhancing effect of sleep deprivation/fragmentation, the temporal association between pain and sleep as experienced by patients is less understood. The current study was conducted to examine the influence of presleep pain on subsequent sleep and sleep on pain reports the next day, taking into consideration other related psychophysiologic variables such as mood and arousal. Design: A daily process study, involving participants to monitor their pain, sleep, mood, and presleep arousal for 1 wk. Multilevel modeling was used to analyze the data. Setting: In the patients' natural living and sleeping environment. Patients: One hundred nineteen patients (73.9% female, mean age = 46 years) with chronic pain and concomitant insomnia. Measurement: An electronic diary was used to record patients' self-reported sleep quality/efficiency and ratings of pain, mood, and arousal at different times of the day; actigraphy was also used to provide estimates of sleep efficiency. Results: Results indicated that presleep pain was not a reliable predictor of subsequent sleep. Instead, sleep was better predicted by presleep cognitive arousal. Although sleep quality was a consistent predictor of pain the next day, the pain-relieving effect of sleep was only evident during the first half of the day. Conclusions: These findings challenge the often-assumed reciprocal relationship between pain and sleep and call for a diversification in thinking of the daily interaction of these 2 processes. Citation: Tang NKY; Goodchild CE; Sanborn AN; Howard J; Salkovskis PM. Deciphering the temporal link between pain and sleep in a heterogeneous chronic pain patient sample: a multilevel daily process study. SLEEP 2012;35(5):675-687. PMID:22547894
Pain management in trauma: A review study
Ahmadi, Alireza; Bazargan-Hejazi, Shahrzad; Heidari Zadie, Zahra; Euasobhon, Pramote; Ketumarn, Penkae; Karbasfrushan, Ali; Amini-Saman, Javad; Mohammadi, Reza
Abstract: Background: Pain in trauma has a role similar to the double-edged sword. On the one hand, pain is a good indicator to determine the severity and type of injury. On the other hand, pain can induce sever complications and it may lead to further deterioration of the patient. Therefore, knowing how to manage pain in trauma patients is an important part of systemic approach in trauma. The aim of this manuscript is to provide information about pain management in trauma in the Emergency Room settings. Methods: In this review we searched among electronic and manual documents covering a 15-yr period between 2000 and 2016. Our electronic search included Pub Med, Google scholar, Web of Science, and Cochrane databases. We looked for articles in English and in peer-reviewed journals using the following keywords: acute pain management, trauma, emergency room and injury. Results: More than 3200 documents were identified. After screening based on the study inclusion criteria, 560 studies that had direct linkage to the study aim were considered for evaluation based World Health Organization (WHO) pain ladder chart. Conclusions: To provide adequate pain management in trauma patients require: adequate assessment of age-specific pharmacologic pain management; identification of adequate analgesic to relieve moderate to severe pain; cognizance of serious adverse effects of pain medications and weighting medications against their benefits, and regularly reassessing patients and reevaluating their pain management regimen. Patient-centered trauma care will also require having knowledge of barriers to pain management and discussing them with the patient and his/her family to identify solutions. PMID:27414816
Complex regional pain syndrome (CRPS) or continuous unilateral distal experimental pain stimulation in healthy subjects does not bias visual attention towards one hemifield.
Filippopulos, Filipp M; Grafenstein, Jessica; Straube, Andreas; Eggert, Thomas
In natural life pain automatically draws attention towards the painful body part suggesting that it interacts with different attentional mechanisms such as visual attention. Complex regional pain syndrome (CRPS) patients who typically report on chronic distally located pain of one extremity may suffer from so-called neglect-like symptoms, which have also been linked to attentional mechanisms. The purpose of the study was to further evaluate how continuous pain conditions influence visual attention. Saccade latencies were recorded in two experiments using a common visual attention paradigm whereby orientating saccades to cued or uncued lateral visual targets had to be performed. In the first experiment saccade latencies of healthy subjects were measured under two conditions: one in which continuous experimental pain stimulation was applied to the index finger to imitate a continuous pain situation, and one without pain stimulation. In the second experiment saccade latencies of patients suffering from CRPS were compared to controls. The results showed that neither the continuous experimental pain stimulation during the experiment nor the chronic pain in CRPS led to an unilateral increase of saccade latencies or to a unilateral increase of the cue effect on latency. The results show that unilateral, continuously applied pain stimuli or chronic pain have no or only very limited influence on visual attention. Differently from patients with visual neglect, patients with CRPS did not show strong side asymmetries of saccade latencies or of cue effects on saccade latencies. Thus, neglect-like clinical symptoms of CRPS patients do not involve the allocation of visual attention.
Antinociceptive Interaction of Tramadol with Gabapentin in Experimental Mononeuropathic Pain.
Miranda, Hugo F; Noriega, Viviana; Prieto, Juan Carlos; Zanetta, Pilar; Castillo, Rodrigo; Aranda, Nicolás; Sierralta, Fernando
Neuropathic pain is the result of injury to the nervous system, and different animal models have been established to meet the manifestations of neuropathy. The pharmacotherapy for neuropathic pain includes gabapentin and tramadol, but these are only partially effective when given alone. The aim of this study was to assess the antinociceptive interaction between both drugs using the isobolographic analysis and changes of the IL-1β concentration in a mouse model of neuropathic pain (partial sciatic nerve ligation or PSNL). The i.p. administration of gabapentin (5-100 mg/kg) or tramadol (12.5-100 mg/kg) displayed a dose-dependent antinociception in the hot plate assay of PSNL mice, and effects induced by gabapentin with tramadol were synergistic. Administration of gabapentin or tramadol reversed significantly the increase in the concentration of IL-1β induced by PSNL after either 7 or 14 days and their combination was significantly more potent in reversing the elevated concentration of IL-1β. The synergism obtained by the co-administration of gabapentin and tramadol is proposed to result from action on different mechanisms in pain pathways. Gabapentin or tramadol or their combination modulates the expression of pro-inflammatory cytokine, IL-1β, in a model of mice PSNL which could be due to an inhibition of glial function.
Pain Sensitivity and Opioid Analgesia: A Pharmacogenomic Twin Study
Angst, Martin S.; Phillips, Nicholas G.; Drover, David R.; Tingle, Martha; Ray, Amrita; Swan, Gary E.; Lazzeroni, Laura C.; Clark, J. David
Opioids are the cornerstone medication for the management of moderate to severe pain. Unfortunately, vast inter-individual differences in dose requirements complicate their effective and safe clinical use. Mechanisms underlying such differences are incompletely understood, are likely multifactorial, and include genetic and environmental contributions. While accumulating evidence suggests that variants of several genes account for some of the observed response variance, the relative contribution of these factors remains unknown. This study used a twin paradigm to provide a global estimate of the genetic and environmental contributions to inter-individual differences in pain sensitivity and analgesic opioid effects. Eighty one monozygotic and 31 dizygotic twin pairs successfully underwent a computer-controlled infusion with the muopioid agonist alfentanil in a single occasion, randomized, double-blind and placebo-controlled study design. Pain sensitivity and analgesic effects were assessed with experimental heat and cold pressor pain models along with important covariates including demographic factors, depression, anxiety, and sleep quality. Significant heritability was detected for cold pressor pain tolerance and opioid-mediated elevations in heat and cold pressor pain thresholds. Genetic effects accounted for 12–60% of the observed response variance. Significant familial effects accounting for 24–32% of observed variance were detected for heat and cold pressor pain thresholds and opioid-mediated elevation in cold pressor pain tolerance. Significant covariates included age, gender, race, education, and anxiety. Results provide a strong rationale for more detailed molecular genetic studies to elucidate mechanisms underlying inter-individual differences in pain sensitivity and analgesic opioid responses. Such studies will require careful consideration of the studied pain phenotype. PMID:22444188
Spinal segmental and supraspinal mechanisms underlying the pain-relieving effects of spinal cord stimulation: an experimental study in a rat model of neuropathy.
Barchini, J; Tchachaghian, S; Shamaa, F; Jabbur, S J; Meyerson, B A; Song, Z; Linderoth, B; Saadé, N E
Spinal cord stimulation (SCS) may alleviate certain forms of neuropathic pain; its mechanisms of action are, however, not fully understood. Previous studies have mainly been focused onto segmental spinal mechanisms, though there is evidence indicating a supraspinal involvement. This study aims to evaluate the relative importance of segmental and supraspinal mechanisms related to the activation of the dorsal columns (DCs). Rats were used to induce the spared nerve injury neuropathy and simultaneously subjected to chronic bilateral DC lesions at the C6-C8 level. Two pairs of miniature electrodes were implanted in each animal, with a monopolar system placed in the dorsal epidural space at a low thoracic level (below lesion) and a bipolar system placed onto the dorsal column nuclei (above lesion). Stimulation (50 Hz, 0.2 ms, 2-4V, 5 min) was applied via either type of electrodes, and tests for sensitivity to tactile and thermal stimuli were used to assess its inhibitory effects. Various receptor antagonists {bicuculline (GABA(A)), saclofen (GABA(B)), ketanserine (5HT(2)), methysergide (5HT(1-2)), phentolamine (α-adrenergic), propranolol (β-adrenergic), sulpiride (D(2)/D(3) dopamine) or saline were injected prior to the SCS. Rostral and caudal stimulations produced a comparable inhibition of neuropathic manifestations, and these effects were attenuated by about 50% after DC lesions. Pretreatment with the various receptor antagonists differentially influenced the effects of rostral and caudal stimulation. Our findings suggest that both supraspinal and segmental mechanisms are activated by SCS, and that in this model with DC lesions, rostral and caudal stimulations may activate different synaptic circuitries and transmitter systems.
The effect of cognitive bias modification for interpretation on avoidance of pain during an acute experimental pain task.
Jones, Emma Blaisdale; Sharpe, Louise
Research confirms that patients with chronic pain show a tendency to interpret ambiguous stimuli as pain related. However, whether modifying these interpretive pain biases impacts pain outcomes is unknown. This study aimed to demonstrate that interpretation biases towards pain can be modified, and that changing these biases influences pain outcomes in the cold pressor task. One hundred and six undergraduate students were randomly allocated to receive either threatening or reassuring information regarding the cold pressor. They also were randomly allocated to 1 of 2 conditions in the Ambiguous Scenarios Task, in which they were trained to have either a threatening interpretation of pain (pain bias condition) or a nonthreatening interpretation of pain (no pain bias condition). Therefore, the study had a 2 (threat/reassuring)×2 (pain bias/no pain bias) design. Analyses showed that a bias was induced contingent on condition, and that the threat manipulation was effective. Participants in the pain bias condition hesitated more before doing the cold pressor task than those in the no pain bias condition, as did those in the threat compared with the reassurance condition. The major finding was that interpretive bias mediated the relationship between bias condition and hesitance time, supporting the causal role of interpretive biases for avoidance behaviors in current chronic pain models. No differences were found on other pain outcomes regarding bias or threat, and the efficacy of the bias modification was not impacted by different levels of threat. These results suggest that cognitive bias modification should be further explored as a potential intervention in pain.
Endogenous Opioid Antagonism in Physiological Experimental Pain Models: A Systematic Review
Werner, Mads U.; Pereira, Manuel P.; Andersen, Lars Peter H.; Dahl, Jørgen B.
Opioid antagonists are pharmacological tools applied as an indirect measure to detect activation of the endogenous opioid system (EOS) in experimental pain models. The objective of this systematic review was to examine the effect of mu-opioid-receptor (MOR) antagonists in placebo-controlled, double-blind studies using ʻinhibitory' or ʻsensitizing', physiological test paradigms in healthy human subjects. The databases PubMed and Embase were searched according to predefined criteria. Out of a total of 2,142 records, 63 studies (1,477 subjects [male/female ratio = 1.5]) were considered relevant. Twenty-five studies utilized ʻinhibitory' test paradigms (ITP) and 38 studies utilized ʻsensitizing' test paradigms (STP). The ITP-studies were characterized as conditioning modulation models (22 studies) and repetitive transcranial magnetic stimulation models (rTMS; 3 studies), and, the STP-studies as secondary hyperalgesia models (6 studies), ʻpain' models (25 studies), summation models (2 studies), nociceptive reflex models (3 studies) and miscellaneous models (2 studies). A consistent reversal of analgesia by a MOR-antagonist was demonstrated in 10 of the 25 ITP-studies, including stress-induced analgesia and rTMS. In the remaining 14 conditioning modulation studies either absence of effects or ambiguous effects by MOR-antagonists, were observed. In the STP-studies, no effect of the opioid-blockade could be demonstrated in 5 out of 6 secondary hyperalgesia studies. The direction of MOR-antagonist dependent effects upon pain ratings, threshold assessments and somatosensory evoked potentials (SSEP), did not appear consistent in 28 out of 32 ʻpain' model studies. In conclusion, only in 2 experimental human pain models, i.e., stress-induced analgesia and rTMS, administration of MOR-antagonist demonstrated a consistent effect, presumably mediated by an EOS-dependent mechanisms of analgesia and hyperalgesia. PMID:26029906
Coping With Pain: Studies in Stress Inoculation.
ERIC Educational Resources Information Center
Horan, John J.; And Others
The stress-inoculation paradigm for helping clients deal with pain consists of education about the psychological dimensions of pain, training in a number of coping skills relevant to each dimension, and practice in applying these skills to the noxious stimulus. Presented are two studies, the first of which represents a component analysis of stress…
Kinesthetic illusions attenuate experimental muscle pain, as do muscle and cutaneous stimulation.
Gay, André; Aimonetti, Jean-Marc; Roll, Jean-Pierre; Ribot-Ciscar, Edith
In the present study, muscle pain was induced experimentally in healthy subjects by administrating hypertonic saline injections into the tibialis anterior (TA) muscle. We first aimed at comparing the analgesic effects of mechanical vibration applied to either cutaneous or muscle receptors of the TA or to both types simultaneously. Secondly, pain alleviation was compared in subjects in whom muscle tendon vibration evoked kinesthetic illusions of the ankle joint. Muscle tendon vibration, which primarily activated muscle receptors, reduced pain intensity by 30% (p<0.01). In addition, tangential skin vibration reduced pain intensity by 33% (p<0.01), primarily by activating cutaneous receptors. Concurrently stimulating both sensory channels induced stronger analgesic effects (-51%, p<0.01), as shown by the lower levels of electrodermal activity. The strongest analgesic effects of the vibration-induced muscle inputs occurred when illusory movements were perceived (-38%, p=0.01). The results suggest that both cutaneous and muscle sensory feedback reduce muscle pain, most likely via segmental and supraspinal processes. Further clinical trials are needed to investigate these new methods of muscle pain relief.
Statins alleviate experimental nerve injury-induced neuropathic pain.
Shi, Xiang Qun; Lim, Tony K Y; Lee, Seunghwan; Zhao, Yuan Qing; Zhang, Ji
The statins are a well-established class of drugs that lower plasma cholesterol levels by inhibiting HMG-CoA (3-hydroxy-3-methyl-glutaryl-coenzyme A) reductase. They are widely used for the treatment of hypercholesterolemia and for the prevention of coronary heart disease. Recent studies suggest that statins have anti-inflammatory effects beyond their lipid-lowering properties. We sought to investigate whether statins could affect neuropathic pain by mediating nerve injury-associated inflammatory responses. The effects of hydrophilic rosuvastatin and lipophilic simvastatin were examined in the mouse partial sciatic nerve ligation model. Systemic daily administration of either statin from days 0 to 14 completely prevented the development of mechanical allodynia and thermal hyperalgesia. When administered from days 8 to 14 after injury, both statins dose-dependently reduced established hypersensitivity. After treatment, the effects of the statins were washed out within 2 to 7 days, depending on dose. Effects of both statins in alleviating mechanical allodynia were further confirmed in a different injury-associated neuropathic pain model, mental nerve chronic constriction, in rats. Both statins were able to abolish interleukin-1β expression in sciatic nerve triggered by nerve ligation. Additionally, quantitative analysis with Iba-1 and glial fibrillary acid protein immunoreactivity demonstrated that rosuvastatin and simvastatin significantly reduced the spinal microglial and astrocyte activation produced by sciatic nerve injury. The increase of interleukin-1β mRNA in the ipsilateral side of spinal cords was also reduced by the treatment of either statin. We identified a potential new application of statins in the treatment of neuropathic pain. The pain-alleviating effects of statins are likely attributable to their immunomodulatory effects.
The genetic influences on oxycodone response characteristics in human experimental pain.
Olesen, Anne E; Sato, Hiroe; Nielsen, Lecia M; Staahl, Camilla; Droney, Joanne; Gretton, Sophy; Branford, Ruth; Drewes, Asbjørn M; Arendt-Nielsen, Lars; Riley, Julia; Ross, Joy
Human experimental pain studies are of value to study basic pain mechanisms under controlled conditions. The aim of this study was to investigate whether genetic variation across selected mu-, kappa- and delta-opioid receptor genes (OPRM1, OPRK1and OPRD1, respectively) influenced analgesic response to oxycodone in healthy volunteers. Experimental multimodal, multitissue pain data from previously published studies carried out in Caucasian volunteers were used. Data on thermal skin pain tolerance threshold (PTT) (n = 37), muscle pressure PTT (n = 31), mechanical visceral PTT (n = 43) and thermal visceral PTT (n = 41) were included. Genetic associations with pain outcomes were explored. Nineteen opioid receptor genetic polymorphisms were included in this study. Variability in oxycodone response to skin heat was associated with OPRM1 single-nucleotide polymorphisms (SNPs) rs589046 (P < 0.0001) and rs563649 (P < 0.0001). Variability in oxycodone response to visceral pressure was associated with four OPRM1 SNPs: rs589046 (P = 0.015), rs1799971 (P = 0.045), rs9479757 (P = 0.009) and rs533586 (P = 0.046). OPRM1 SNPs were not associated with oxycodone visceral heat threshold, however, one OPRD1 rs419335 reached significance (P = 0.015). Another OPRD1 SNP rs2234918 (P = 0.041) was associated with muscle pressure. There were no associations with OPRK1 SNPs and oxycodone response for any of the pain modalities. Associations were found between analgesic effects of oxycodone and OPRM1 and OPRD1 SNPs; therefore, variation in opioid receptor genes may partly explain responder characteristics to oxycodone.
Assessment of knee joint pain in experimental rodent models of osteoarthritis.
Piel, Margaret J; Kroin, Jeffrey S; Im, Hee-Jeong
Pain assessment in animal models of osteoarthritis is integral to interpretation of a model's utility in representing the clinical condition, and enabling accurate translational medicine. Here we describe two methods for behavioral pain assessments available for use in animal models of experimental osteoarthritic pain: Von Frey filaments and spontaneous activity monitoring.
The impact of neurodynamic testing on the perception of experimentally induced muscle pain.
Coppieters, Michel W; Kurz, Kimberly; Mortensen, Thor Einar; Richards, Nicola L; Skaret, Ingrid A; McLaughlin, Laurie M; Hodges, Paul W
Neurodynamic tests such as the straight leg raising (SLR) and slump test are frequently used for assessment of mechanosensitivity of neural tissues. However, there is ongoing debate in the literature regarding the contributions of neural and non-neural tissues to the elicited symptoms because many structures are affected by these tests. Sensitizing manoeuvres are limb or spinal movements added to neurodynamic tests, which aim to identify the origin of the symptoms by preferentially loading or unloading neural structures. A prerequisite for the use of sensitizing manoeuvres to identify neural involvement is that the addition of sensitizing manoeuvres has no impact on pain perception when the origin of the pain is non-neural. In this study, experimental muscle pain was induced by injection of hypertonic saline in tibialis anterior or soleus in 25 asymptomatic, naive volunteers. A first experiment investigated the impact of hip adduction, abduction, medial and lateral rotation in the SLR position. In a second experiment, the different stages of the slump test were examined. The intensity and area of experimentally induced muscle pain did not increase when sensitizing manoeuvres were added to the SLR or throughout the successive stages of the slump test. The findings of this study lend support to the validity of the use of sensitizing manoeuvres during neurodynamic testing.
The Pain Management Life History Calendar: A Pilot Study.
McDonald, Deborah Dillon; Barri, Caroline
Pain management trajectory data that includes previous pain treatments, timing, changes, and outcomes provide crucial data for patients with chronic pain and their practitioners to use when discussing ways to optimize pain management regimens. The aim of this study was to test the use of the life history calendar method to identify pain treatments, treatment regimens, timing, and outcomes of the pain management trajectory of individuals with chronic pain, and to examine feasibility. A pilot, descriptive, methodological design was used. Settings included community-based sites such as congregate housing. Nineteen community-dwelling older adults with osteoarthritis (OA) pain of at least 1 year's duration participated. Participants were interviewed and asked to chronicle from the beginning of the OA pain to the present all of their pain treatments and treatment effects (pain outcomes and adverse events). Raters independently content analyzed the transcribed interviews to identify pain treatments, treatment groupings (regimens), and treatment effects on pain. Feasibility of patients reporting their pain management trajectories was content analyzed by identifying participant difficulty identifying pain treatments, treatment effects, treatment sequence; and difficulty discriminating between treatments, and between OA pain and other pain sources. Individual pain management trajectories were constructed that depicted chronological order of pain treatment regimens and treatment effects. Participants identified pain treatments, discriminate between treatments and between OA and other conditions, and identified treatment effects. Treatment sequence was identified, but more precise timing was generally not reported. Pain management trajectories could provide a helpful way for practitioners to discuss safe, efficacious pain management options with patients.
Comparison of pain scale preferences and pain intensity according to pain scales among Turkish Patients: a descriptive study.
Yazici Sayin, Yazile; Akyolcu, Neriman
Pain scale preferences may vary among patients. Providing a choice of which pain scale to use might be helpful for patients. The aim of this study was to determine patient pain scale preferences and compare the level of agreement among pain scales commonly used during postoperative pain assessment. A total of 621 patients during the early postoperative period were enrolled in this descriptive study. A questionnaire form, the faces pain scale (FPS), visual analog scale (VAS), numeric rating scale (NRS), verbal descriptor scale (VDS), thermometer pain scale (TPS), McGill Pain Questionnaire (MPQ), Short-form McGill Pain Questionnaire (SFMPQ), and Brief Pain Inventory (BPI) were used to collect data. Most patients reported that their pain was not measured with any of the pain scales. Patient preference for pain scales were as follows: 97.4% FPS, 88.6% NRS, 84.1% VDS, 78.1% TPS, 60.1% SFMPQ, 37.0% BPI, 11.4% VAS, and 10.5% MPQ. Education was an important factor in the preferences for all scales (p < .000). The level of pain determined by the VAS did not correlate with the level of pain identified by the NRS, TPS, FPS, and VDS (p < .05). There was no difference among the levels of pain for the NRS, TPS, FPS and VDS (p > .05), but there was for the VAS (p < .05). The pain scales chosen should be reliable, valid, and able to evaluate the effects of treatment. The results suggest that the NRS, TPS, FPS, and VDS were appropriate pain rating scales for the participants in this study, and that the VAS should be used in combination with one of these scales.
Concept priming and pain: an experimental approach to understanding gender roles in sex-related pain differences.
Fowler, Stephanie L; Rasinski, Heather M; Geers, Andrew L; Helfer, Suzanne G; France, Christopher R
Prior research has found that sex differences in pain are partially due to individual variations in gender roles. In a laboratory study, we tested the hypothesis that the presence of covert gender role cues can also moderate the extent to which women and men experience pain. Specifically, we varied gender role cues by asking male and female participants to write about instances in which they behaved in a stereotypically feminine, masculine, or neutral manner. Pain and cardiovascular reactivity to the cold pressor task were then assessed. Results revealed that, when primed with femininity, men reported less pain and anxiety from the cold pressor task than women. However, no differences existed between the sexes in the masculine or neutral prime conditions. The results indicate that covert gender cues can alter pain reports. Further, at least in some situations, feminine role cues may be more influential on pain reports than masculine role cues.
IL-17 is not essential for inflammation and chronic pelvic pain development in an experimental model of chronic prostatitis/chronic pelvic pain syndrome.
Motrich, Ruben D; Breser, María L; Sánchez, Leonardo R; Godoy, Gloria J; Prinz, Immo; Rivero, Virginia E
Pain and inflammation in the absence of infection are hallmarks in chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS) patients. The etiology of CP/CPPS is unclear, and autoimmunity has been proposed as a cause. Experimental autoimmune prostatitis (EAP) models have long been used for studying CP/CPPS. Herein, we studied prostate inflammation induction and chronic pelvic pain development in EAP using IL-12p40-KO, IL-4-KO, IL-17-KO, and wild-type (C57BL/6) mice. Prostate antigen (PAg) immunization in C57BL/6 mice induced specific Th1 and Th17 immune responses and severe prostate inflammation and cell infiltration, mainly composed of CD4 T cells and macrophages. Moreover, chronic pelvic pain was evidenced by increased allodynia responses. In immunized IL-17-KO mice, the presence of a prominent PAg-specific Th1 immune response caused similar prostate inflammation and chronic pelvic pain. Furthermore, markedly high PAg-specific Th1 immune responses, exacerbated prostate inflammation, and chronic pelvic pain were detected in immunized IL-4-KO mice. Conversely, immunized IL-12p40-KO mice developed PAg-specific Th2 immune responses, characterized by high IL-4 secretion and neither infiltration nor damage in the prostate. As observed in wild-type control animals, IL12p40-KO mice did not evidence tactile allodynia responses. Our results suggest that, as in patients, chronic pelvic pain is a consequence of prostate inflammation. After PAg immunization, a Th1-associated immune response develops and induces prostate inflammation and chronic pelvic pain. The absence of Th1 or Th2 cytokines, respectively, diminishes or enhances EAP susceptibility. In addition, IL-17 showed not to be essential for pathology induction and chronic pelvic pain development.
Experimental pain processing in individuals with cognitive impairment: current state of the science.
Defrin, Ruth; Amanzio, Martina; de Tommaso, Marina; Dimova, Violeta; Filipovic, Sasa; Finn, David P; Gimenez-Llort, Lydia; Invitto, Sara; Jensen-Dahm, Christina; Lautenbacher, Stefan; Oosterman, Joukje M; Petrini, Laura; Pick, Chaim G; Pickering, Gisele; Vase, Lene; Kunz, Miriam
Cognitive impairment (CI) can develop during the course of ageing and is a feature of many neurological and neurodegenerative diseases. Many individuals with CI have substantial, sustained, and complex health care needs, which frequently include pain. However, individuals with CI can have difficulty communicating the features of their pain to others, which in turn presents a significant challenge for effective diagnosis and treatment of their pain. Herein, we review the literature on responsivity of individuals with CI to experimental pain stimuli. We discuss pain responding across a large number of neurological and neurodegenerative disorders in which CI is typically present. Overall, the existing data suggest that pain processing is altered in most individuals with CI compared with cognitively intact matched controls. The precise nature of these alterations varies with the type of CI (or associated clinical condition) and may also depend on the type of pain stimulation used and the type of pain responses assessed. Nevertheless, it is clear that regardless of the etiology of CI, patients do feel noxious stimuli, with more evidence for hypersensitivity than hyposensitivity to these stimuli compared with cognitively unimpaired individuals. Our current understanding of the neurobiological mechanisms underpinning these alterations is limited but may be enhanced through the use of animal models of CI, which also exhibit alterations in nociceptive responding. Further research using additional behavioural indices of pain is warranted. Increased understanding of altered experimental pain processing in CI will facilitate the development of improved diagnostic and therapeutic approaches for pain in individuals with CI.
Effect of endocannabinoid degradation on pain: role of FAAH polymorphisms in experimental and postoperative pain in women treated for breast cancer.
Cajanus, Kristiina; Holmström, Emil J; Wessman, Maija; Anttila, Verneri; Kaunisto, Mari A; Kalso, Eija
Fatty acid amide hydrolase (FAAH) metabolizes the endocannabinoid anandamide, which has an important role in nociception. We investigated the role of common FAAH single-nucleotide polymorphisms (SNPs) in experimentally induced and postoperative pain. One thousand women undergoing surgery for breast cancer participated in the study. They were tested for cold (n = 900) and heat pain (n = 1000) sensitivity. After surgery, their pain intensities and analgesic consumption were carefully registered. FAAH genotyping was performed using MassARRAY platform and genome-wide chip (n = 926). Association between 8 FAAH SNPs and 9 pain phenotypes was analyzed using linear regression models. The results showed that carrying 2 copies of a missense variant converting proline at position 129 to threonine (rs324420) resulted in significantly lower cold pain sensitivity and less need for postoperative analgesia. More specifically, rs324420 and another highly correlated SNP, rs1571138, associated significantly with cold pain intensity (corrected P value, 0.0014; recessive model). Patients homozygous for the minor allele (AA genotype) were less sensitive to cold pain (β = -1.48; 95% CI, -2.14 to -0.8). Two other SNPs (rs3766246 and rs4660928) showed nominal association with cold pain, and SNPs rs4141964, rs3766246, rs324420, and rs1571138 nominal association with oxycodone consumption. In conclusion, FAAH gene variation was shown to associate with cold pain sensitivity with P129T/rs324420 being the most likely causal variant as it is known to reduce the FAAH enzyme activity. The same variant showed nominal association with postoperative oxycodone consumption. Our conclusions are, however, limited by the lack of replication and the results should be replicated in an independent cohort.
Magnetohydrodynamic generator experimental studies
NASA Technical Reports Server (NTRS)
Pierson, E. S.
The results for an experimental study of a one wavelength MHD induction generator operating on a liquid flow are presented. First the design philosophy and the experimental generator design are summarized, including a description of the flow loop and instrumentation. Next a Fourier series method of treating the fact that the magnetic flux density produced by the stator is not a pure traveling sinusoid is described and some results summarized. This approach appears to be of interest after revisions are made, but the initial results are not accurate. Finally, some of the experimental data is summarized for various methods of excitation.
Antihyperalgesic effect of pentoxifylline on experimental inflammatory pain
Vale, Mariana L; Benevides, Verônica M; Sachs, Daniela; Brito, Gerly A C; da Rocha, Francisco A C; Poole, Stephen; Ferreira, Sérgio H; Cunha, Fernando Q; Ribeiro, Ronaldo A
The antihyperalgesic effect of pentoxifylline was investigated in three experimental pain models. Pentoxifylline (0.5–1.6 mg kg−1) given 30 min before the stimulus significantly inhibited the writhing response induced by the intraperitoneal (i.p.) administration of either acetic acid (−90%) or zymosan (−83%), but not that of iloprost, in mice, as well as the zymosan-induced articular hyperalgesia in the zymosan arthritis in rats (−50%). Pentoxifylline also inhibited the mechanical hypernociception in rats induced by the intraplantar injection of either carrageenin (−81%), bradykinin (−56%) or tumor necrosis factor α (TNF-α; −46%), but not that induced by interleukin-1β (IL-1β) or prostaglandin E2 (PGE2). Pentoxifylline did not inhibit the nociceptive response in the hot plate test in mice. Further, the antinociceptive effect of pentoxifylline in the writhing test in mice and the zymosan-induced articular hyperalgesia were not reversed by the coadministration of the opioid receptor antagonist naloxone. Thus, pentoxifylline antinociceptive effect is probably not mediated at a central level. Pentoxifylline significantly reduced TNF-α (−43%) and IL-1β (−42%) concentrations in the joint exudates of rats stimulated by intra-articular injection of zymosan and the production of both cytokines (−66 and −86%, respectively) by mouse peritoneal macrophages stimulated in vivo with zymosan as well as the expression of TNF-α at the tissue level in carrageenin-injected rat paws. In conclusion, the antinociceptive activity of pentoxifylline is associated with the inhibition of the release of both TNF-α and IL-1β. PMID:15520047
Antihyperalgesic effect of pentoxifylline on experimental inflammatory pain.
Vale, Mariana L; Benevides, Verônica M; Sachs, Daniela; Brito, Gerly A C; da Rocha, Francisco A C; Poole, Stephen; Ferreira, Sérgio H; Cunha, Fernando Q; Ribeiro, Ronaldo A
The antihyperalgesic effect of pentoxifylline was investigated in three experimental pain models. Pentoxifylline (0.5-1.6 mg kg(-1)) given 30 min before the stimulus significantly inhibited the writhing response induced by the intraperitoneal (i.p.) administration of either acetic acid (-90%) or zymosan (-83%), but not that of iloprost, in mice, as well as the zymosan-induced articular hyperalgesia in the zymosan arthritis in rats (-50%). Pentoxifylline also inhibited the mechanical hypernociception in rats induced by the intraplantar injection of either carrageenin (-81%), bradykinin (-56%) or tumor necrosis factor alpha (TNF-alpha; -46%), but not that induced by interleukin-1beta (IL-1beta) or prostaglandin E(2) (PGE(2)). Pentoxifylline did not inhibit the nociceptive response in the hot plate test in mice. Further, the antinociceptive effect of pentoxifylline in the writhing test in mice and the zymosan-induced articular hyperalgesia were not reversed by the coadministration of the opioid receptor antagonist naloxone. Thus, pentoxifylline antinociceptive effect is probably not mediated at a central level. Pentoxifylline significantly reduced TNF-alpha (-43%) and IL-1beta (-42%) concentrations in the joint exudates of rats stimulated by intra-articular injection of zymosan and the production of both cytokines (-66 and -86%, respectively) by mouse peritoneal macrophages stimulated in vivo with zymosan as well as the expression of TNF-alpha at the tissue level in carrageenin-injected rat paws. In conclusion, the antinociceptive activity of pentoxifylline is associated with the inhibition of the release of both TNF-alpha and IL-1beta.
Sex differences in pain: a brief review of clinical and experimental findings
Bartley, E. J.; Fillingim, R. B.
Summary Recent years have witnessed substantially increased research regarding sex differences in pain. The expansive body of literature in this area clearly suggests that men and women differ in their responses to pain, with increased pain sensitivity and risk for clinical pain commonly being observed among women. Also, differences in responsivity to pharmacological and non-pharmacological pain interventions have been observed; however, these effects are not always consistent and appear dependent on treatment type and characteristics of both the pain and the provider. Although the specific aetiological basis underlying these sex differences is unknown, it seems inevitable that multiple biological and psychosocial processes are contributing factors. For instance, emerging evidence suggests that genotype and endogenous opioid functioning play a causal role in these disparities, and considerable literature implicates sex hormones as factors influencing pain sensitivity. However, the specific modulatory effect of sex hormones on pain among men and women requires further exploration. Psychosocial processes such as pain coping and early-life exposure to stress may also explain sex differences in pain, in addition to stereotypical gender roles that may contribute to differences in pain expression. Therefore, this review will provide a brief overview of the extant literature examining sex-related differences in clinical and experimental pain, and highlights several biopsychosocial mechanisms implicated in these male–female differences. The future directions of this field of research are discussed with an emphasis aimed towards further elucidation of mechanisms which may inform future efforts to develop sex-specific treatments. PMID:23794645
Helicopter pilot back pain: a preliminary study.
Shanahan, D F; Reading, T E
Because of the high prevalence of back pain experienced by U.S. Army helicopter pilots, a study was conducted to ascertain the feasibility of reproducing these symptoms in the laboratory. A mock-up of a UH-1H seat and control configuration was mounted to a multi-axis vibration simulator (MAVS). Eleven subjects were tested on the apparatus for two 120-min periods. During one period, the MAVS was programmed to reproduce vibrations recorded from a UH-1H in cruise flight. The subjects received no vibration during the other test period. All subjects reported back pain which they described as identical to the pain they experience during flight, during one or more of their test periods. There was no statistical difference between the vibration and nonvibration test conditions (p greater than 0.05) in terms of time of onset of pain or intensity of pain as measured by a visual analog scale. It appears the vibration at the frequencies and amplitudes tested plays little or no role in the etiology of the back symptoms reported by these pilots. It is proposed that the primary etiological factor for these symptoms is the poor posture pilots are obliged to assume for extended periods while operating helicopters.
Antihypernociceptive activity of anethole in experimental inflammatory pain.
Ritter, Alessandra M V; Domiciano, Talita P; Verri, Waldiceu A; Zarpelon, Ana Carla; da Silva, Lorena G; Barbosa, Carmem P; Natali, Maria Raquel M; Cuman, Roberto K N; Bersani-Amado, Ciomar A
Anethole has been reported to have antioxidant, antibacterial, antifungal, antiinflammatory, and anesthetic properties. In the present study, we evaluated the effects of anethole in two pain models of inflammatory origin: acute inflammation induced by carrageenan and persistent inflammation induced by Complete Freund's adjuvant. We evaluated the effects of anethole (125, 250, and 500 mg/kg) on the development of paw oedema and mechanical hypernociception. The liver was collected for histological analysis. Paw skin was collected to determine the levels of the cytokines tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-17 (IL-17), and myeloperoxidase activity. Blood was collected to assess alanine transaminase (ALT) and aspartate transaminase (AST). The chemical composition of star anise oil was determined by gas chromatography/mass spectrometry (GC/MS), showing a presence of anethole of 98.1%. Oral pretreatment with anethole in mice inhibited paw oedema, mechanical pernociception, myelopewroxidase activity, TNF-α, IL-1β and IL-17 levels in acute and persistent inflammation models. Additionally, anethole treatment did not alter prostaglandin E2-induced mechanical hypernociception. Possible side effects were also examined. Seven-day anethole treatment did not alter plasma AST and ALT levels, and the histological profile of liver tissue was normal. The present study provides evidence of the antiinflammatory and analgesic activities of anethole in acute and persistent inflammation models.
Spinal Disinhibition in Experimental and Clinical Painful Diabetic Neuropathy.
Marshall, Andrew G; Lee-Kubli, Corinne; Azmi, Shazli; Zhang, Michael; Ferdousi, Maryam; Mixcoatl-Zecuatl, Teresa; Petropoulos, Ioannis N; Ponirakis, Georgios; Fineman, Mark S; Fadavi, Hassan; Frizzi, Katie; Tavakoli, Mitra; Jeziorska, Maria; Jolivalt, Corinne G; Boulton, Andrew J M; Efron, Nathan; Calcutt, Nigel A; Malik, Rayaz A
Impaired rate dependent depression (RDD) of the Hoffman-reflex is associated with reduced dorsal spinal cord potassium chloride co-transporter expression and impaired spinal GABAA receptor function, indicative of spinal inhibitory dysfunction. We have investigated the pathogenesis of impaired RDD in diabetic rodents exhibiting features of painful neuropathy and the translational potential of this marker of spinal inhibitory dysfunction in human painful diabetic neuropathy. Impaired RDD and allodynia were present in type 1 and type 2 diabetic rats but not in rats with type 1 diabetes receiving insulin supplementation that did not restore normoglycemia. Impaired RDD in diabetic rats was rapidly normalized by spinal delivery of duloxetine acting via 5HT2A receptors and temporally coincident with the alleviation of allodynia. Deficits in RDD and corneal nerve density were demonstrated in patients with painful diabetic neuropathy when compared to healthy control subjects and patients with painless diabetic neuropathy. Spinal inhibitory dysfunction and peripheral small fibre pathology may contribute to the clinical phenotype in painful diabetic neuropathy. Deficits in RDD may help to identify patients with spinally mediated painful diabetic neuropathy who may respond optimally to therapies such as duloxetine.
Satisfaction with and Perception of Pain Management among Palliative Patients with Breakthrough Pain: A Qualitative Study.
Pathmawathi, Subramanian; Beng, Tan Seng; Li, Lee Mei; Rosli, Roshaslina; Sharwend, Supermanian; Kavitha, Rasaiah R; Christopher, Boey Chiong Meng
Breakthrough pain is a significant contributor to much suffering by patients. The experience of intense pain may interfere with, and affect, daily life functioning and has major consequences on patients' well-being if it is not well managed. The area of breakthrough pain has not been fully understood. This study thus aimed to explore the experiences of breakthrough pain among palliative patients. A qualitative study based on a series of open-ended interviews among 21 palliative patients suffering from pain at an urban tertiary hospital in Malaysia was conducted. Five themes were generated: (i) pain viewed as an unbearable experience causing misery in the lives of patients, (ii) deterioration of body function and no hope of recovery, (iii) receiving of inadequate pain management for pain, (iv) insensitivity of healthcare providers toward patients' pain experience, and (v) pain coping experiences of patients. The findings revealed that nonpharmacologic approaches such as psychosocial support should be introduced to the patients. Proper guidance and information should be given to healthcare providers to improve the quality of patient care. Healthcare providers should adopt a sensitive approach in caring for patients' needs. The aim is to meet the needs of the patients who want to be pain free or to attain adequate relief of their pain for breakthrough pain.
Pain Intensity and Pain Interference in patients with lung cancer: A pilot study of Biopsychosocial Predictors
Dalton, Jo Ann; Higgins, Melinda K.; Miller, Andrew H.; Keefe, Francis J.; Khuri, Fadlo R.
Objective To explore biopsychosocial factors (beliefs, depression, catastrophizing cytokines) in individuals newly diagnosed with lung cancer and no pain in order to determine their relationship at diagnosis and across time and to determine whether these factors contribute to pain intensity or pain interference with function at pain onset. Methods A longitudinal, exploratory, pilot study was implemented in a private medical center and a VA medical center in the southeast. Twelve subjects not experiencing pain related to cancer of the lung or its treatment were recruited. A Karnofsky status of 40% and Hemoglobin of 8 grams were required. Five questionnaires were completed and 10 cc of blood was drawn at Baseline; 4 questionnaires and blood draws were repeated monthly for 5 months. One Baseline questionnaire and a pain assessment were added at Final. Demographic, clinical and questionnaire data were summarized; standardized scale scores were calculated. Results Biopsychosocial scores that were low at Baseline increased from T1-T4 but decreased slightly T5-T6. Individuals with higher pain intensity and higher pain interference at Final had higher psychosocial scores at Baseline than individuals with lower pain intensity and lower pain interference at Final. Conclusions Unrelated to disease stage, metastasis or treatment, unique, levels of biopsychosocial factors are observed in patients newly diagnosed with lung cancer who report higher levels of Pain Intensity and higher levels of Pain Interference at the time pain occurs. Replication studies are needed to validate this response pattern and determine the value of repeated individual assessments. PMID:24064756
Tryptase - PAR2 axis in Experimental Autoimmune Prostatitis, a model for Chronic Pelvic Pain Syndrome
Roman, Kenny; Done, Joseph D.; Schaeffer, Anthony J.; Murphy, Stephen F.; Thumbikat, Praveen
Chronic prostatitis/Chronic pelvic pain syndrome (CP/CPPS) affects up to 15% of the male population and is characterized by pelvic pain. Mast cells are implicated in the murine experimental autoimmune prostatitis (EAP) model as key to chronic pelvic pain development. The mast cell mediator tryptase-β and its cognate receptor protease-activated receptor 2 (PAR2) are involved in mediating pain in other visceral disease models. Prostatic secretions and urines from CP/CPPS patients were examined for the presence of mast cell degranulation products. Tryptase-β and PAR2 expression were examined in murine experimental autoimmune prostatitis (EAP). Pelvic pain and inflammation were assessed in the presence or absence of PAR2 expression and upon PAR2 neutralization. Tryptase-β and carboxypeptidase A3 were elevated in CP/CPPS compared to healthy volunteers. Tryptase-β was capable of inducing pelvic pain and was increased in EAP along with its receptor PAR2. PAR2 was required for the development of chronic pelvic pain in EAP. PAR2 signaling in dorsal root ganglia lead to ERK1/2 phosphorylation and calcium influx. PAR2 neutralization using antibodies attenuated chronic pelvic pain in EAP. The tryptase-PAR2 axis is an important mediator of pelvic pain in EAP and may play a role in the pathogenesis of CP/CPPS. PMID:24726923
Side effects of pain and analgesia in animal experimentation.
Jirkof, Paulin
This review highlights selected effects of untreated pain and of widely used analgesics such as opioids, non-steroid anti-inflammatory drugs and antipyretics, to illustrate the relevance of carefully planned, appropriate and controlled analgesia for greater reproducibility in animal experiments involving laboratory rodents.
Atypical orofacial pain disorders: a study of diagnostic subtypes.
Fricton, J R
Atypical facial pain is a persistent pain in the face or intraoral region that does not fit into the diagnostic criteria associated with specific orofacial pain disorders. This article presents the results of a study, which showed that in most cases of presumed atypical facial pain, there is a specific physical diagnosis or multiple diagnoses that causes the persistent pain. These difficult to diagnose disorders are reviewed with discussion of future research that is needed in this area.
Tryptase-PAR2 axis in experimental autoimmune prostatitis, a model for chronic pelvic pain syndrome.
Roman, Kenny; Done, Joseph D; Schaeffer, Anthony J; Murphy, Stephen F; Thumbikat, Praveen
Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) affects up to 15% of the male population and is characterized by pelvic pain. Mast cells are implicated in the murine experimental autoimmune prostatitis (EAP) model as key to chronic pelvic pain development. The mast cell mediator tryptase-β and its cognate receptor protease-activated receptor 2 (PAR2) are involved in mediating pain in other visceral disease models. Prostatic secretions and urines from CP/CPPS patients were examined for the presence of mast cell degranulation products. Tryptase-β and PAR2 expression were examined in murine EAP. Pelvic pain and inflammation were assessed in the presence or absence of PAR2 expression and upon PAR2 neutralization. Tryptase-β and carboxypeptidase A3 were elevated in CP/CPPS compared to healthy volunteers. Tryptase-β was capable of inducing pelvic pain and was increased in EAP along with its receptor PAR2. PAR2 was required for the development of chronic pelvic pain in EAP. PAR2 signaling in dorsal root ganglia led to extracellular signal-regulated kinase (ERK)1/2 phosphorylation and calcium influx. PAR2 neutralization using antibodies attenuated chronic pelvic pain in EAP. The tryptase-PAR2 axis is an important mediator of pelvic pain in EAP and may play a role in the pathogenesis of CP/CPPS.
Effect of experimental low back pain on neuromuscular control of the trunk in healthy volunteers and patients with chronic low back pain.
Dubois, Jean-Daniel; Piché, Mathieu; Cantin, Vincent; Descarreaux, Martin
Studies of electromyographic (EMG) activity and lumbopelvic rhythm have led to a better understanding of neuromuscular alterations in chronic low back pain (cLBP) patients. Whether these changes reflect adaptations to chronic pain or are induced by acute pain is still unclear. This work aimed to assess the effects of experimental LBP on lumbar erector spinae (LES) EMG activity and lumbopelvic kinematics during a trunk flexion-extension task in healthy volunteers and LBP patients. The contribution of disability to these effects was also examined. Twelve healthy participants and 14 cLBP patients performed flexion-extension tasks in three conditions; control, innocuous heat and noxious heat, applied on the skin over L5 or T7. The results indicated that noxious heat at L5 evoked specific increases in LES activity during static full trunk flexion and extension, irrespective of participants' group. Kinematic data suggested that LBP patients adopted a different movement strategy than controls when noxious heat was applied at the L5 level. Besides, high disability was associated with less kinematic changes when approaching and leaving full flexion. These results indicate that experimental pain can induce neuromechanical alterations in cLBP patients and healthy volunteers, and that higher disability in patients is associated with decreased movement pattern changes.
Improving Pain Management and Long-Term Outcomes Following High-Energy Orthopaedic Trauma (Pain Study).
Castillo, Renan C; Raja, Srinivasa N; Frey, Katherine P; Vallier, Heather A; Tornetta, Paul; Jaeblon, Todd; Goff, Brandon J; Gottschalk, Allan; Scharfstein, Daniel O; O'Toole, Robert V
Poor pain control after orthopaedic trauma is a predictor of physical disability and numerous negative long-term outcomes. Despite increased awareness of the negative consequences of poorly controlled pain, analgesic therapy among hospitalized patients after orthopaedic trauma remains inconsistent and often inadequate. The Pain study is a 3 armed, prospective, double-blind, multicenter randomized trial designed to evaluate the effect of standard pain management versus standard pain management plus perioperative nonsteroidal anti-inflammatory drugs or pregabalin in patients of ages 18-85 with extremity fractures. The primary outcomes are chronic pain, opioid utilization during the 48 hours after definitive fixation and surgery for nonunion in the year after fixation. Secondary outcomes include preoperative and postoperative pain intensity, adverse events and complications, physical function, depression, and post-traumatic stress disorder. One year treatment costs are also compared between the groups.
Imaging studies in patients with spinal pain
Ferrari, Robert
Abstract Objective To evaluate an a priori threshold for advanced imaging in patients with spinal pain. Design Patients with spinal pain in any region for 6 to 52 weeks were assessed to determine if radiologic studies beyond x-ray scans were indicated, including magnetic resonance imaging (MRI), computed tomography (CT), and radionuclide bone scans. An a priori threshold was set before MRI, CT, or bone scans would be considered. Those who did not have MRI, CT, or bone scans ordered were followed for at least 1 year to determine if any of them went on to be diagnosed with a more serious spinal disorder (eg, infection, fracture, spondylitis, tumour, neurologic compression). Setting Four large primary care clinics in Edmonton, Alta. Participants A total of 1003 consecutively presenting patients with symptoms suspected to be related to the spine (for a duration of generally 6 to 52 weeks) who had not already undergone advanced imaging and did not have a diagnosis of nonbenign back pain. Main outcome measures Number of cases of nonbenign spinal disorder in participants who underwent advanced imaging and participants who did not undergo advanced imaging (ie, did not have any red flags). Results There were 399 women (39.8%) and 604 men (60.2%). The mean (SD) age of the group was 47.2 (14.6) years. The mean (SD) duration of symptoms was 15.1 (8.6) weeks. Of the 1003 participants, 110 met an a priori threshold for undergoing at least 1 of MRI, CT, or bone scan. In these 110 participants, there were newly diagnosed cases of radiculopathy (n = 12), including a case of cauda equina syndrome; spondyloarthropathy (n = 6); occult fracture (n = 2); solitary metastasis (n = 1); epidural lipomatosis (n = 1); osteomyelitis (n = 1), and retroperitoneal hematoma (n = 1), each of which was considered likely to be the cause of the patient's spinal symptoms. The remaining 893 participants were followed for at least 1 year and none showed evidence of a nonbenign cause of his or her
Experimental muscle pain increases variability of neural drive to muscle and decreases motor unit coherence in tremor frequency band
Yavuz, Utku Ş.; Negro, Francesco; Falla, Deborah
It has been observed that muscle pain influences force variability and low-frequency (<3 Hz) oscillations in the neural drive to muscle. In this study, we aimed to investigate the effect of experimental muscle pain on the neural control of muscle force at higher frequency bands, associated with afferent feedback (alpha band, 5–13 Hz) and with descending cortical input (beta band, 15–30 Hz). Single-motor unit activity was recorded, in two separate experimental sessions, from the abductor digiti minimi (ADM) and tibialis anterior (TA) muscles with intramuscular wire electrodes, during isometric abductions of the fifth finger at 10% of maximal force [maximum voluntary contraction (MVC)] and ankle dorsiflexions at 25% MVC. The contractions were repeated under three conditions: no pain (baseline) and after intramuscular injection of isotonic (0.9%, control) and hypertonic (5.8%, painful) saline. The results showed an increase of the relative power of both the force signal and the neural drive at the tremor frequency band (alpha, 5–13 Hz) between the baseline and hypertonic (painful) conditions for both muscles (P < 0.05) but no effect on the beta band. Additionally, the strength of motor unit coherence was lower (P < 0.05) in the hypertonic condition in the alpha band for both muscles and in the beta band for the ADM. These results indicate that experimental muscle pain increases the amplitude of the tremor oscillations because of an increased variability of the neural control (common synaptic input) in the tremor band. Moreover, the concomitant decrease in coherence suggests an increase in independent input in the tremor band due to pain. PMID:26019314
High- and low-frequency transcutaneous electrical nerve stimulation does not reduce experimental pain in elderly individuals
Bergeron-Vézina, Kayla; Corriveau, Hélène; Martel, Marylie; Harvey, Marie-Philippe; Léonard, Guillaume
Abstract Despite its widespread clinical use, the efficacy of transcutaneous electrical nerve stimulation (TENS) remains poorly documented in elderly individuals. In this randomized, double-blind crossover study, we compared the efficacy of high-frequency (HF), low-frequency (LF), and placebo (P) TENS in a group of 15 elderly adults (mean age: 67 ± 5 years). The effect of HF-, LF-, and P-TENS was also evaluated in a group of 15 young individuals (26 ± 5 years; same study design) to validate the effectiveness of the TENS protocols that were used in the elderly group. Each participant came to the laboratory on 3 separate occasions to receive, in random order, HF-, LF-, and P-TENS. Pain intensity and pain perception thresholds were assessed before, during, and after TENS, using an experimental heat pain paradigm. For the young group, there was a significant decrease in pain intensity during and after HF- and LF-TENS when compared with baseline, with both HF- and LF-TENS being superior to P-TENS. In the older group, HF- and LF-TENS did not reduce pain when compared with baseline and no difference was observed between the 2 active TENS sessions and P-TENS. High-frequency, LF-, and P-TENS all increased pain thresholds in young individuals, whereas in older individuals, only LF-TENS increased pain thresholds. Taken together, these results suggest that TENS is effective in young, but not in older, individuals. Future studies should be conducted to confirm these results in pain populations and to identify strategies that could enhance the effect of TENS in the elderly. PMID:26101836
High- and low-frequency transcutaneous electrical nerve stimulation does not reduce experimental pain in elderly individuals.
Bergeron-Vézina, Kayla; Corriveau, Hélène; Martel, Marylie; Harvey, Marie-Philippe; Léonard, Guillaume
Despite its widespread clinical use, the efficacy of transcutaneous electrical nerve stimulation (TENS) remains poorly documented in elderly individuals. In this randomized, double-blind crossover study, we compared the efficacy of high-frequency (HF), low-frequency (LF), and placebo (P) TENS in a group of 15 elderly adults (mean age: 67 ± 5 years). The effect of HF-, LF-, and P-TENS was also evaluated in a group of 15 young individuals (26 ± 5 years; same study design) to validate the effectiveness of the TENS protocols that were used in the elderly group. Each participant came to the laboratory on 3 separate occasions to receive, in random order, HF-, LF-, and P-TENS. Pain intensity and pain perception thresholds were assessed before, during, and after TENS, using an experimental heat pain paradigm. For the young group, there was a significant decrease in pain intensity during and after HF- and LF-TENS when compared with baseline, with both HF- and LF-TENS being superior to P-TENS. In the older group, HF- and LF-TENS did not reduce pain when compared with baseline and no difference was observed between the 2 active TENS sessions and P-TENS. High-frequency, LF-, and P-TENS all increased pain thresholds in young individuals, whereas in older individuals, only LF-TENS increased pain thresholds. Taken together, these results suggest that TENS is effective in young, but not in older, individuals. Future studies should be conducted to confirm these results in pain populations and to identify strategies that could enhance the effect of TENS in the elderly.
Understanding venous leg ulcer pain: results of a longitudinal study.
Nemeth, Kathleen A; Harrison, Margaret B; Graham, Ian D; Burke, Sharon
Venous leg ulcer pain experienced during compression bandaging is poorly understood. A prospective, pilot cohort study was initiated to determine the feasibility of conducting a large-scale, repeated measures cohort study of venous leg ulcer pain and to document and describe the venous leg ulcer pain experience during the first 5 weeks of treatment with compression bandages. Eligible individuals admitted to a nurse-led community leg ulcer service in one Canadian community were recruited for the 5-week study. Pain assessment tools (ie, numerical rating scale and short form McGill Pain Questionnaire) were evaluated by 20 venous ulcer patients (mean age = 73.7 years) and their nurses for ease of use during one baseline and five weekly follow-up visits. Health-related quality of life (HRQL) information was obtained. Nurses reported on ease of integrating pain data collection into regular clinical care. Each pain assessment tool was audited for completion. Most participants found the pain assessment tools easy to use, but nurses reported lengthened visit times with some participants as a result of tool administration difficulties, particularly the visual analogue scale (VAS). Overall completeness of pain assessment tools ranged from 85.0% (visual analogue scale) to 96.3% (present pain intensity and word descriptor list). The vast majority of patients (18) reported ulcer pain at baseline. Total mean scores for all pain assessment tools used decreased over time, but most patients reported pain throughout the study. The most common pain descriptors used were "aching," "stabbing," "sharp," "tender," and "tiring." Health-related quality of life was low and did not change during the 5-week study. The results of this study suggest that the vast majority of venous ulcer patients experience pain and that it is feasible to examine this pain in individuals receiving care in the community over time.
Pain in multiple sclerosis: A systematic review of neuroimaging studies
Seixas, D.; Foley, P.; Palace, J.; Lima, D.; Ramos, I.; Tracey, I.
Introduction While pain in multiple sclerosis (MS) is common, in many cases the precise mechanisms are unclear. Neuroimaging studies could have a valuable role in investigating the aetiology of pain syndromes. The aim of this review was to synthesise and appraise the current literature on neuroimaging studies of pain syndromes in MS. Methods We systematically searched PubMed and Scopus from their inception dates to the 2nd of April 2013. Studies were selected by predefined inclusion and exclusion criteria. Methodological quality was appraised. Descriptive statistical analysis was conducted. Results We identified 38 studies of variable methodology and quality. All studies but one used conventional structural magnetic resonance imaging, and the majority reported a positive association between location of demyelinating lesions and specific neuropathic pain syndromes. Most investigated headache and facial pain, with more common pain syndromes such as limb pain being relatively understudied. We identified a number of methodological concerns, which along with variable study design and reporting limit our ability to synthesise data. Higher quality studies were however less likely to report positive associations of lesion distribution to pain syndromes. Conclusions Further high quality hypothesis-driven neuroimaging studies of pain syndromes in MS are required to clarify pain mechanisms, particularly for the commonest pain syndromes. PMID:25161898
Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication.
Pasinato, Fernanda; Santos-Couto-Paz, Clarissa C; Zeredo, Jorge Luis Lopes; Macedo, Sergio Bruzadelli; Corrêa, Eliane C R
The aim of this study was to verify the effects of induced masseter-muscle pain on the amplitude of muscle activation, symmetry and coactivation of jaw- and neck-muscles during mastication. Twenty-eight male volunteers, mean age±SD 20.6±2.0years, participated in this study. Surface electromyography of the masseter and sternocleidomastoid (SCM) muscles was performed bilaterally during mastication of a gummy candy before and after injections of monosodium glutamate solution and isotonic saline solution. As a result, we observed a decrease in the amplitude of activation of the masseter muscle on the working side (p=0.009; d=0.34) and a reduction in the asymmetry between the working and the balancing side during mastication (p=0.007; d=0.38). No changes were observed either on the craniocervical electromyographic variables. In conclusion, experimentally induced pain reduced the masseter muscle activation on the working side, thereby reducing the physiological masseters' recruitment asymmetry between the two sides during mastication. No effects on SCM activity were detected. These results may partly explain the initial maladaptative changes underlying TMD conditions.
Burn patients' experience of pain management: a qualitative study.
Yuxiang, Li; Lingjun, Zhou; Lu, Tang; Mengjie, Liu; Xing, Ming; Fengping, Shen; Jing, Cui; Xianli, Meng; Jijun, Zhao
Pain is a major problem after burns and researchers continue to report that pain from burns remains undertreated. The inadequate pain control results in adverse sequalae physically and psychologically in the burn victims. A better understanding of a burn patient's experience is important in identifying the factors responsible for undertreated pain and establishing effective pain management guidelines or recommendation in the practice of pain relief for burn injuries. This study sought to explore and describe the experience that patients have about pain related to burn-injury during hospitalization. Semi-structured interviews were conducted on eight patients with moderate to severe pain from burn injuries recruited from a Burn Centre in Northwest China. Data was collected by in-depth interviews and qualitative description after full transcription of each interview. Analysis involved the identification of themes and the development of a taxonomy of patients' experience of burn pain and its management. Three themes were indentified: (1) patients' experience of pain control, (2) patients' perception on burn pain management, and (3) patients' expectation of burn pain management. Findings from this study suggested that patients experience uncontrolled pain both physically and psychologically which may serve as an alert for awareness of health professionals to recognize and establish a multidisciplinary pain management team for burn victims, including surgeons, critical care specialists, anesthesiologists, nurses, psychologists, and social workers to accomplish safe and effective strategies for pain control to reach an optimal level of pain management in burn patients. It also provides insights and suggestions for future research directions to address this significant clinical problem.
Computerized assessment of pain drawing area: A pilot study
Wenngren, Anna; Stålnacke, Britt-Marie
Aim: To investigate if pain area in patients with chronic pain could be measured by a computerized assessment on previously marked pain drawings on paper figures and to analyze the further application of the method. Methods: Seventy-two patients (54 women and 18 men) who were admitted to Umeå University Hospital during 2003 for assessment of chronic pain answered a set of questionnaires (pain intensity on the visual analog scale [VAS], disability on the Disability Rating Index [DRI], life satisfaction on the LiSat-11) and filled in pain drawings on paper figures of the human body. The pain drawings were later analyzed by using computerized assessment. Results: Women marked a greater pain area than men, but the difference was not significant (p =0.433). No significant difference was shown for the previous seven days between men and women on the VAS (p =0.914), DRI (p =0.493), or LiSat-11 (p =0.124). A statistically significant correlation was found between pain area and VAS for the previous seven days (r =0.250; p =0.046). Pain area was statistically significantly correlated to the DRI (r =0.336; p =0.014) and close to negatively correlated to the LiSat-11 (r =0.687; p =0.057). Conclusion: This pilot study shows that pain drawing area could be measured by a computerized assessment of pain drawings. The method points to the possibility of relating pain area with other instruments. In the present study, an association between the patients' pain drawing area and pain intensity and between pain area and level of activity was shown. PMID:19721724
A prospective study on postoperative pain after cataract surgery
Porela-Tiihonen, Susanna; Kaarniranta, Kai; Kokki, Merja; Purhonen, Sinikka; Kokki, Hannu
Purpose To evaluate postoperative pain and early recovery in cataract patients. Patients and methods A total of 201 patients who underwent elective first eye cataract extraction surgery were enrolled, and 196 were included in the final analysis. The study design was a single-center, prospective, follow-up study in a tertiary hospital in eastern Finland. Postoperative pain was evaluated with the Brief Pain Inventory at four time points: at baseline, and at 24 hours, 1 week, and 6 weeks postsurgery. Results Postoperative pain was relatively common during the first hours after surgery, as it was reported by 67 (34%) patients. After hospital discharge, the prevalence decreased; at 24 hours, 1 week, and 6 weeks, 18 (10%), 15 (9%) and 12 (7%) patients reported having ocular pain, respectively. Most patients with eye pain reported significant pain, with a score of ≥4 on a pain scale of 0–10, but few had taken analgesics for eye pain. Those who had used analgesics rated the analgesic efficacy of paracetamol and ibuprofen as good or excellent. Other ocular irritation symptoms were common after surgery; as a new postoperative symptom, foreign-body sensation was reported by 40 patients (22%), light sensitivity by 29 (16%), burning by 15 (8%), and itching by 15 (8%). Conclusion Moderate or severe postoperative pain was relatively common after cataract surgery. Thus, all patients undergoing cataract surgery should be provided appropriate counseling on pain and pain management after surgery. PMID:23885165
Effect of Experimental Hand Pain on Training-Induced Changes in Motor Performance and Corticospinal Excitability
Mavromatis, Nicolas; Neige, Cécilia; Gagné, Martin; Reilly, Karen T.; Mercier, Catherine
Pain influences plasticity within the sensorimotor system and the aim of this study was to assess the effect of pain on changes in motor performance and corticospinal excitability during training for a novel motor task. A total of 30 subjects were allocated to one of two groups (Pain, NoPain) and performed ten training blocks of a visually-guided isometric pinch task. Each block consisted of 15 force sequences, and subjects modulated the force applied to a transducer in order to reach one of five target forces. Pain was induced by applying capsaicin cream to the thumb. Motor performance was assessed by a skill index that measured shifts in the speed–accuracy trade-off function. Neurophysiological measures were taken from the first dorsal interosseous using transcranial magnetic stimulation. Overall, the Pain group performed better throughout the training (p = 0.03), but both groups showed similar improvements across training blocks (p < 0.001), and there was no significant interaction. Corticospinal excitability in the NoPain group increased halfway through the training, but this was not observed in the Pain group (Time × Group interaction; p = 0.01). These results suggest that, even when pain does not negatively impact on the acquisition of a novel motor task, it can affect training-related changes in corticospinal excitability. PMID:28165363
The predictive value of attentional bias towards pain-related information in chronic pain patients: a diary study.
Van Ryckeghem, Dimitri M L; Crombez, Geert; Goubert, Liesbet; De Houwer, Jan; Onraedt, Thomas; Van Damme, Stefaan
Theoretical accounts of chronic pain hypothesize that attentional bias towards pain-related information is a maintaining or exacerbating factor, fuelling further pain, disability, and distress. However, empirical research testing this idea is currently lacking. In the present study, we investigated whether attentional bias towards pain-related information predicts daily pain-related outcomes in a sample of chronic pain patients (n=69; M(age)=49.64 years; 46 females). During an initial laboratory session, attentional bias to pain-related information was assessed using a modified spatial cueing task. In advance, patients completed a number of self-report measures assessing current pain intensity, current disability, and pain duration. Subsequently, daily pain outcomes (self-reported pain severity, disability, avoidance behaviour, and distractibility) were measured for 2 weeks by means of an electronic diary. Results indicated that, although an attentional bias towards pain-related information was associated with the current level of disability and pain severity, it had no additional value above control variables in predicting daily pain severity, avoidance, distractibility, and disability. Attentional bias towards pain-related information did, however, moderate the relationship between daily pain severity and both daily disability and distractibility, indicating that, particularly in those patients with a strong attentional bias, increases in pain were associated with increased disability and distractibility. The use of interventions that diminish attentional bias may therefore be helpful to reduce daily disability and the level of distraction from current tasks despite the presence of pain in chronic pain patients.
Pain perception and hypnosis: findings from recent functional neuroimaging studies.
Del Casale, Antonio; Ferracuti, Stefano; Rapinesi, Chiara; Serata, Daniele; Caltagirone, Saverio Simone; Savoja, Valeria; Piacentino, Daria; Callovini, Gemma; Manfredi, Giovanni; Sani, Gabriele; Kotzalidis, Georgios D; Girardi, Paolo
Hypnosis modulates pain perception and tolerance by affecting cortical and subcortical activity in brain regions involved in these processes. By reviewing functional neuroimaging studies focusing on pain perception under hypnosis, the authors aimed to identify brain activation-deactivation patterns occurring in hypnosis-modulated pain conditions. Different changes in brain functionality occurred throughout all components of the pain network and other brain areas. The anterior cingulate cortex appears to be central in modulating pain circuitry activity under hypnosis. Most studies also showed that the neural functions of the prefrontal, insular, and somatosensory cortices are consistently modified during hypnosis-modulated pain conditions. Functional neuroimaging studies support the clinical use of hypnosis in the management of pain conditions.
Pelvic pain after childbirth: a longitudinal population study.
Bjelland, Elisabeth Krefting; Owe, Katrine Mari; Pingel, Ronnie; Kristiansson, Per; Vangen, Siri; Eberhard-Gran, Malin
In this longitudinal population study, the aims were to study associations of mode of delivery with new onset of pelvic pain and changes in pelvic pain scores up to 7 to 18 months after childbirth. We included 20,248 participants enrolled in the Norwegian Mother and Child Cohort Study (1999-2008) without preexisting pelvic pain in pregnancy. Data were obtained by 4 self-administered questionnaires and linked to the Medical Birth Registry of Norway. A total of 4.5% of the women reported new onset of pelvic pain 0 to 3 months postpartum. Compared to unassisted vaginal delivery, operative vaginal delivery was associated with increased odds of pelvic pain (adjusted odds ratio [OR]: 1.30; 95% confidence interval [CI]: 1.06-1.59). Planned and emergency cesarean deliveries were associated with reduced odds of pelvic pain (adjusted OR: 0.48; 95% CI: 0.31-0.74 and adjusted OR: 0.65; 95% CI: 0.49-0.87, respectively). Planned cesarean delivery, young maternal age, and low Symptom Checklist-8 scores were associated with low pelvic pain scores after childbirth. A history of pain was the only factor associated with increased pelvic pain scores over time (P = 0.047). We conclude that new onset of pelvic pain after childbirth was not commonly reported, particularly following cesarean delivery. Overall, pelvic pain scores were rather low at all time points and women with a history of pain reported increased pelvic pain scores over time. Hence, clinicians should follow up women with pelvic pain after a difficult childbirth experience, particularly if they have a history of pain.
Effect of Catechol-O-methyltransferase-gene (COMT) Variants on Experimental and Acute Postoperative Pain in 1,000 Women undergoing Surgery for Breast Cancer
Kambur, Oleg; Kaunisto, Mari A.; Tikkanen, Emmi; Leal, Suzanne M.; Ripatti, Samuli; Kalso, Eija A.
Background Catechol-O-methyltransferase (COMT) metabolizes catecholamines in different tissues. Polymorphisms in COMT gene can attenuate COMT activity and increase sensitivity to pain. Human studies exploring the effect of COMT polymorphisms on pain sensitivity have mostly included small, heterogeneous samples and have ignored several important single nucleotide polymorphisms (SNPs). This study examines the effect of COMT polymorphisms on experimental and postoperative pain phenotypes in a large ethnically homogeneous female patient cohort. Methods Intensity of cold (+2–4°C) and heat (+48°C) pain and tolerance to cold pain were assessed in 1,000 patients scheduled for breast cancer surgery. Acute postoperative pain and oxycodone requirements were recorded. Twenty-two COMT SNPs were genotyped and their association with six pain phenotypes analyzed with linear regression. Results There was no association between any of the tested pain phenotypes and SNP rs4680. The strongest association signals were seen between rs165774 and heat pain intensity as well as rs887200 and cold pain intensity. In both cases, minor allele carriers reported less pain. Neither of these results remained significant after strict multiple testing corrections. When analyzed further, the effect of rs887200 was, however, shown to be significant and consistent throughout the cold pressure test. No evidence of association between the SNPs and postoperative oxycodone consumption was found. Conclusions SNPs rs887200 and rs165774 located in the untranslated regions of the gene had the strongest effects on pain sensitivity. Their effect on pain is described here for the first time. These results should be confirmed in further studies and the potential functional mechanisms of the variants studied. PMID:24343288
HDAC inhibitors restore C-fibre sensitivity in experimental neuropathic pain model
Matsushita, Yosuke; Araki, Kohei; Omotuyi, Olaposi idowu; Mukae, Takehiro; Ueda, Hiroshi
Background and Purpose Hypoesthesia is a clinical feature of neuropathic pain. The feature is partly explained by the evidence of epigenetic repression of Nav1.8 sodium channel in the dorsal root ganglion (DRG). Experimental Approach We investigated the possibility of trichostatin A (TSA), valproic acid (VPA) and suberoylanilide hydroxamic acid (SAHA) to reverse the unique C-fibre sensitivity observed following partial ligation of sciatic nerve in mice. Key Results Nerve injury-induced down-regulation of DRG Nav1.8 sodium channel and C-fibre-related hypoesthesia were reversed by TSA, VPA and SAHA treatments, which inhibit histone deacetylase (HDAC), and increase histone acetylation at the regulatory sequence of Nav1.8. Conclusions and Implications Taken together, these studies provide the evidence that hypoesthesia and underlying down-regulation of Nav1.8, negative symptoms observed in nerve injury-induced neuropathic pain models are regulated by an epigenetic chromatin remodelling through HDAC-related machineries. PMID:24032674
Relationship between Temporomandibular Disorders, Widespread Palpation Tenderness and Multiple Pain Conditions: A Case - Control Study
Chen, Hong; Slade, Gary; Lim, Pei Feng; Miller, Vanessa; Maixner, William; Diatchenko, Luda
The multiple bodily pain conditions in temporomandibular disorders (TMD) have been associated with generalized alterations in pain processing. The purpose of this study was to examine the relationship between the presence of widespread body palpation tenderness (WPT) and the likelihood of multiple comorbid pain conditions in TMD patients and controls. This case-control study was conducted in 76 TMD subjects with WPT, 83 TMD subjects without WPT, and 181 non-TMD matched control subjects. The study population was also characterized for clinical pain, experimental pain sensitivity, and related psychological phenotypes. Results showed that (1) TMD subjects reported an average of 1.7 comorbid pain conditions compared to 0.3 reported by the control subjects (p<0.001); (2) Compared to control subjects, the odds ratio (OR) for multiple comorbid pain conditions is higher for TMD subjects with WPT [OR 8.4 (95% CI 3.1–22.8) for TMD with WPT versus OR 3.3 (95% CI 1.3–8.4) for TMD without WPT]; (3) TMD subjects with WPT presented with reduced pressure pain thresholds (PPTs) in both cranial and extra-cranial regions compared to TMD subjects without WPT; and (4) TMD subjects with WPT reported increased somatic symptoms. These findings suggest that pain assessment outside of the orofacial region may prove valuable for the classification, diagnosis, and management of TMD patients. PMID:23031401
Racial bias in pain perception and response: experimental examination of automatic and deliberate processes
Mathur, Vani A.; Richeson, Jennifer A.; Paice, Judith A.; Muzyka, Michael; Chiao, Joan Y.
Racial disparities in pain treatment pose a significant public health and scientific problem. Prior studies demonstrate clinicians and non-clinicians are less perceptive, and suggest less treatment for, the pain of African Americans, relative to European Americans. Here we investigate the effects of explicit/implicit patient race presentation, patient race, and perceiver race on pain perception and response. African American and European American participants rated pain perception, empathy, helping motivation, and treatment suggestion in response to vignettes about patients' pain. Vignettes were accompanied by a rapid (implicit), or static (explicit) presentation of an African or European American patient's face. Participants perceived and responded more to European American patients in the implicit prime condition, when the effect of patient race was below the level of conscious regulation. This effect was reversed when patient race was presented explicitly. Additionally, female participants perceived and responded more to the pain of all patients, relative to male participants, and in the implicit prime condition, African American participants were more perceptive and responsive than European Americans to the pain of all patients. Taken together, these results suggest that known disparities in pain treatment may be largely due to automatic (below the level of conscious regulation), rather than deliberate (subject to conscious regulation) biases. These biases were not associated with traditional implicit measures of racial attitudes, suggesting that biases in pain perception and response may be independent of general prejudice. Perspective Results suggest racial biases in pain perception and treatment are at least partially due to automatic processes. When the relevance of patient race is made explicit, however, biases are attenuated and even reversed. We also find preliminary evidence that African Americans may be more sensitive to the pain of others than
Computed tomographic studies of the painful abdomen
Benson, M.; Bree, R.L.; Schwab, R.E.; Ouimette, M.
Abdominal CT scans were reviewed in a series of 53 patients who had abdominal pain without objective physical, radiographic, or laboratory abnormalities. Forty patients presented with abdominal pain alone, while the remaining patients had abdominal pain associated with nausea, vomiting or mild weight loss. Abdominal CT scans in all patients were interpreted as normal. One patient had a pancreatic carcinoma discovered at surgery one month after the CT scan was obtained. The patients were followed up for 6 to 12 months to confirm absence of significant disease. Our analysis suggests a very low yield from abdominal CT in patients with abdominal pain and no other objective findings.
Pain in Alzheimer's disease: A study of behavior and neural correlates
NASA Astrophysics Data System (ADS)
Beach, Paul Anthony
Alzheimer's disease (AD) is a devastating neurodegenerative disease characterized by insidious and progressive impairment of cognition, emotion, and memory. Though pain in patients with AD is a major medical concern it is under diagnosed and under treated in patients, compared to cognitively healthy elderly. Further complicating matters, subjective self-report of pain by becomes increasingly compromised with disease progression; this often leaves clinicians and caregivers no choice but to rely on discerning pain from behavior alone. Patients also report pain at a lower frequency and intensity than healthy seniors (HS). These findings, coupled with recognition that AD pathology affects many pain processing brain regions, have prompted examination of whether AD alters pain perception. While there is evidence that AD actually predisposes heightened perception of pain, several issues remain: experimental work is limited to a handful of studies, whose results have been inconsistent; few examinations of pain in AD have included patients with advanced disease; the neural mechanism underlying altered pain in AD is not clear. I addressed these gaps in the literature by examining subjective, behavioral, and autonomic pain responses in 33 HS and 38 patients with varying severities of AD. A subset of these subjects (24 HS and 20 AD) were scanned, using fMRI. I then determined how the functional connectivity of various resting-state networks (RSNs) were associated with measured pain responses. I found that AD patients rated low-level stimuli as more painful than HS. Also, patients, regardless of severity, showed greater degrees of pain behaviors than HS - both with respect to global behaviors as measured by a clinical pain scale and facial responses as measured by an experimental tool. In contrast, autonomic responses were blunted with advancing AD. Altered pain responses in AD were associated with altered function of RSNs involved in attention and internal mentation, affect
Pain anticipatory phenomena in patients with central poststroke pain: a magnetoencephalography study.
Gopalakrishnan, Raghavan; Burgess, Richard C; Lempka, Scott F; Gale, John T; Floden, Darlene P; Machado, Andre G
Central poststroke pain (CPSP) is characterized by hemianesthesia associated with unrelenting chronic pain. The final pain experience stems from interactions between sensory, affective, and cognitive components of chronic pain. Hence, managing CPSP will require integrated approaches aimed not only at the sensory but also the affective-cognitive spheres. A better understanding of the brain's processing of pain anticipation is critical for the development of novel therapeutic approaches that target affective-cognitive networks and alleviate pain-related disability. We used magnetoencephalography (MEG) to characterize the neural substrates of pain anticipation in patients suffering from intractable CPSP. Simple visual cues evoked anticipation while patients awaited impending painful (PS), nonpainful (NPS), or no stimulus (NOS) to their nonaffected and affected extremities. MEG responses were studied at gradiometer level using event-related fields analysis and time-frequency oscillatory analysis upon source localization. On the nonaffected side, significantly greater responses were recorded during PS. PS (vs. NPS and NOS) exhibited significant parietal and frontal cortical activations in the beta and gamma bands, respectively, whereas NPS (vs. NOS) displayed greater activation in the orbitofrontal cortex. On the affected extremity, PS (vs. NPS) did not show significantly greater responses. These data suggest that anticipatory phenomena can modulate neural activity when painful stimuli are applied to the nonaffected extremity but not the affected extremity in CPSP patients. This dichotomy may stem from the chronic effects of pain on neural networks leading to habituation or saturation. Future clinically effective therapies will likely be associated with partial normalization of the neurophysiological correlates of pain anticipation.
Predictors of opioid efficacy in patients with chronic pain: A prospective multicenter observational cohort study
Olesen, Anne E.; Gram, Mikkel; Jonsson, Torsten; Kamp-Jensen, Michael; Andresen, Trine; Nielsen, Christian; Pozlep, Gorazd; Pfeiffer-Jensen, Mogens; Morlion, Bart; Drewes, Asbjørn M.
Opioids are increasingly used for treatment of chronic pain. However, they are only effective in a subset of patients and have multiple side effects. Thus, studies using biomarkers for response are highly warranted. The current study prospectively examined 63 opioid-naïve patients initiating opioid use for diverse types of chronic pain at five European centers. Quantitative sensory testing, electroencephalography (EEG) recordings, and assessment of pain catastrophizing were performed prior to treatment. The co-primary outcomes were change from baseline in ratings of chronic pain and quality of life after 14 days of opioid treatment. Secondary outcomes included patient's global impression of clinical change and side effects. Logistic regression models adjusted for age and sex were used to identify biomarkers predictive for successful treatment, defined as at least a 30% reduction in average pain intensity or an improvement in quality of life of at least 10 scale points. Fifty-nine patients (94%) completed the study. The mean age was 55 ± 16 years and 69% were females. Pain reduction was predicted by cold pain intensity (OR: 0.69; P = 0.01), pain catastrophizing (OR: 0.82; P = 0.03), relative delta (OR: 0.76; P = 0.03) and beta EEG activity (OR: 1.18; P = 0.04) induced by experimental cold pain. None of the study variables were related to improvement in quality of life. For the first time, individual pain processing characteristics have been linked to opioid response in a mixed chronic pain population. This has the potential to personalize treatment of chronic pain and restrict opioid use to patients with high likelihood for response. PMID:28158269
Demographic Predictors of Pain Sensitivity: Results From the OPPERA Study.
Ostrom, Cara; Bair, Eric; Maixner, William; Dubner, Ronald; Fillingim, Roger B; Ohrbach, Richard; Slade, Gary D; Greenspan, Joel D
The demographic factors of sex, age, and race/ethnicity are well recognized as relevant to pain sensitivity and clinical pain expression. Of these, sex differences have been the most frequently studied, and most of the literature describes greater pain sensitivity for women. The other 2 factors have been less frequently evaluated, and current literature is not definitive. Taking advantage of the large Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) study cohort, we evaluated the association of sex, age, and self-reported race with 34 measures of pressure, mechanical, and thermal pain sensitivity encompassing threshold and suprathreshold perception. Women were significantly more pain-sensitive than men for 29 of 34 measures. Age effects were small, and only significant for 7 of 34 measures, however, the age range was limited (18-44 years of age). Race/ethnicity differences varied across groups and pain assessment type. Non-Hispanic white individuals were less pain-sensitive than African-American (for 21 of 34 measures), Hispanic (19 of 34), and Asian (6 of 34) individuals. No pain threshold measure showed significant racial differences, whereas several suprathreshold pain measures did. This suggests that racial differences are not related to tissue characteristics or inherent nociceptor sensitivity. Rather, the differences observed for suprathreshold pain ratings or tolerance are more likely related to differences in central nociceptive processing, including modulation imposed by cognitive, psychological, and/or affective factors.
Continuous neurophatic orofacial pain: A retrospective study of 23 cases
Sotorra-Figuerola, Dídac; Sánchez-Torres, Alba; Valmaseda-Castellón, Eduard
Background To determine the clinical characteristics of Continuous Neuropathic Orofacial Pain in patients that suffer Persistent Idiopathic Facial Pain (PIFP), Painful Post-Traumatic Trigeminal Neuropathy (PPTTN) or Burning Mouth Syndrome (BMS) and to describe their treatment. Material and Methods A retrospective observational study was made, reviewing the clinical history of the patients diagnosed with Continuous Neuropathic Orofacial Pain between 2004 and 2011 at the Orofacial Pain Unit of the Master of Oral Surgery and Implantology of the University of Barcelona and at the Orofacial Pain Unit of the Teknon Medical Center of Barcelona. Results The average age of the patients with Continuous Neuropathic Orofacial Pain was 54.5, with a clear female predominance (86.9%, n=20). Of all patients, 60.9% (n=14) were suffering a PIFP, 21.7% (n=5) had a BMS and 17.4% (n=4) were presenting a PPTTN. The pain quality described by the patients with Continuous Neuropathic Orofacial Pain was oppressive (43.47%, n=10), widely represented by patients with PIFP, and burning (39.13%, n=9) being the only quality that described patients with BMS. The treatment carried out with the patients was only pharmacologic. The most used drugs for the treatment of PIFP and PPTTN were clonazepam (50%, n=9) and amitriptyline (44.44%, n=8). However, a 55.5% (n=10) of the patients with PIFP or PPTTN required the association of two or more drugs for a correct pain control. All the patients with BMS responded satisfactorily to clonazepam. Conclusions Continuous Neuropathic Orofacial Pain is a little known condition among the general population, physicians and dentists. This favors a late diagnosis and inaccurate treatments which entail unnecessary suffering. It is important to inform both the general population and health professionals concerning this painful condition. Key words:Continuous neuropathic orofacial pain, persistent idiopathic facial pain, painful post-traumatic trigeminal neuropathy
Effect of adenoviral delivery of prodynorphin gene on experimental inflammatory pain induced by formalin in rats
Chen, Xionggang; Wang, Tingting; Lin, Caizhu; Chen, Baihong
Circumstantial evidences suggest that dynorphins and their common precursor prodynorphin (PDYN) are involved in antinociception and neuroendocrine signaling. DREAM knockout mice had increased levels of PDYN and dynorphin expression, and reduced sensitivity to painful stimuli. However, some data support the notion that the up-regulation of spinal dynorphin expression is a common critical feature in neuropathic pain. It is not clear whether the production of dynorphin A can be increased when more PDYN is present. In this study we investigated the changes in pain behaviors, spinal PDYN mRNA expression and dynorphin A production on formalin-induced pain in rats receiving the pretreatment of adenoviral delivery of PDYN. Our results showed that the adenoviral transfer of PDYN gene was sufficient to reduce pain behaviors resulting from formalin injection, and the antinociceptive effect after receiving the pretreatment of adenoviral delivery of PDYN was mediated at the level of the spinal cord via KOR. PMID:25663984
Effect of Experimental Cutaneous Hand Pain on Corticospinal Excitability and Short Afferent Inhibition
Mercier, Catherine; Gagné, Martin; Reilly, Karen T.; Bouyer, Laurent J.
Sensorimotor integration is altered in people with chronic pain. While there is substantial evidence that pain interferes with neural activity in primary sensory and motor cortices, much less is known about its impact on integrative sensorimotor processes. Here, the short latency afferent inhibition (SAI) paradigm was used to assess sensorimotor integration in the presence and absence of experimental cutaneous heat pain applied to the hand. Ulnar nerve stimulation was combined with transcranial magnetic stimulation to condition motor evoked potentials (MEPs) in the first dorsal interosseous muscle. Four interstimulus intervals (ISI) were tested, based on the latency of the N20 component of the afferent sensory volley (N20−5 ms, N20+2 ms, N20+4 ms, N20+10 ms). In the PAIN condition, MEPs were smaller compared to the NEUTRAL condition (p = 0.005), and were modulated as a function of the ISI (p = 0.012). Post-hoc planned comparisons revealed that MEPs at N20+2 and N20+4 were inhibited compared to unconditioned MEPs. However, the level of inhibition (SAI) was similar in the PAIN and NEUTRAL conditions. This suggests that the interplay between pain and sensorimotor integration is not mediated through direct and rapid pathways as assessed by SAI, but rather might involve higher-order integrative areas. PMID:27690117
Opioid treatment of experimental pain activates nuclear factor-κB
Compton, Peggy; Griffis, Charles; Breen, Elizabeth Crabb; Torrington, Matthew; Sadakane, Ryan; Tefera, Eshetu; Irwin, Michael R.
Objective To determine the independent and combined effects of pain and opioids on the activation of an early marker of inflammation, nuclear factor-κB (NF-κB). Design NF-κB activation was compared within-subjects following four randomly ordered experimental sessions of opioid-only (intravenous fentanyl 1 μg/kg), pain-only (cold-pressor), opioid + pain, and a resting condition. Setting University General Clinical Research Center. Participants Twenty-one (11 female) healthy controls. Interventions Following exposure to treatment (fentanyl administration and/or cold-pressor pain), blood samples for NF-kB analysis were obtained. Main outcome measures Intracellular levels of activated NF-κB, in unstimulated and stimulated peripheral blood mononuclear cells at 15 and 30 minutes. Results Neither pain nor opioid administration alone effected NF-κB levels in cell populations; however, the combination of treatments induced significant increases of NF-κB in stimulated peripheral blood mononuclear cell, lymphocytes, and monocytes. Conclusions The combination of acute pain with opioids, as occurs in clinical situations, activates a key transcription factor involved in proinflammatory responses. PMID:25901477
Antinociceptive effect of botulinum toxin type A on experimental abdominal pain.
Drinovac, Višnja; Bach-Rojecky, Lidija; Babić, Ana; Lacković, Zdravko
Visceral pain, especially in the abdominal region, represents one of the most common types of pain. Its chronic form is usually very hard to treat by conventional analgesic agents and adjuvants. We investigated the antinociceptive effect of botulinum toxin type A (BTX-A) in male Wistar rats in two models of visceral pain: peritonitis induced by intraperitoneal injection of 1% acetic acid and colitis induced by intracolonic instillation of 0.1% capsaicin. Pain was measured as the number of abdominal writhes. Additionally, referred mechanical sensitivity in the ventral abdominal area was evaluated by von Frey test and the extent of spinal c-Fos expression was immunohistochemically examined. BTX-A significantly reduced the number of abdominal writhes in both models of visceral pain after intrathecal application in a dose of 2 U/kg. In the experimental colitis model, BTX-A (2 U/kg) reduced both referred mechanical allodynia and c-Fos expression in the dorsal horn of the spinal cord (S2/S3 segments). In contrast to intrathecal administration, BTX-A (2 U/kg) administered into the cisterna magna had no effect on pain suggesting that the primary site of its action is a spinal cord.
Pilot study of a compassion meditation intervention in chronic pain
Chapin, Heather L; Darnall, Beth D; Seppala, Emma M; Doty, James R; Hah, Jennifer M; Mackey, Sean C
Background The emergence of anger as an important predictor of chronic pain outcomes suggests that treatments that target anger may be particularly useful within the context of chronic pain. Eastern traditions prescribe compassion cultivation to treat persistent anger. Compassion cultivation has been shown to influence emotional processing and reduce negativity bias in the contexts of emotional and physical discomfort, thus suggesting it may be beneficial as a dual treatment for pain and anger. Our objective was to conduct a pilot study of a 9-week group compassion cultivation intervention in chronic pain to examine its effect on pain severity, anger, pain acceptance and pain-related interference. We also aimed to describe observer ratings provided by patients' significant others and secondary effects of the intervention. Methods Pilot clinical trial with repeated measures design that included a within-subjects wait-list control period. Twelve chronic pain patients completed the intervention (F= 10). Data were collected from patients at enrollment, treatment baseline and post-treatment; participant significant others contributed data at the enrollment and post-treatment time points. Results In this predominantly female sample, patients had significantly reduced pain severity and anger and increased pain acceptance at post-treatment compared to treatment baseline. Significant other qualitative data corroborated patient reports for reductions in pain severity and anger. Conclusions Compassion meditation may be a useful adjunctive treatment for reducing pain severity and anger, and for increasing chronic pain acceptance. Patient reported reductions in anger were corroborated by their significant others. The significant other corroborations offer a novel contribution to the literature and highlight the observable emotional and behavioral changes in the patient participants that occurred following the compassion intervention. Future studies may further examine how
Experimental orofacial pain and sensory deprivation lead to perceptual distortion of the face in healthy volunteers.
Dagsdóttir, Lilja Kristín; Skyt, Ina; Vase, Lene; Baad-Hansen, Lene; Castrillon, Eduardo; Svensson, Peter
Patients suffering from persistent orofacial pain may sporadically report that the painful area feels "swollen" or "differently," a phenomenon that may be conceptualized as a perceptual distortion because there are no clinical signs of swelling present. Our aim was to investigate whether standardized experimental pain and sensory deprivation of specific orofacial test sites would lead to changes in the size perception of these face areas. Twenty-four healthy participants received either 0.2 mL hypertonic saline (HS) or local anesthetics (LA) into six regions (buccal, mental, lingual, masseter muscle, infraorbital and auriculotemporal nerve regions). Participants estimated the perceived size changes in percentage (0 % = no change, -100 % = half the size or +100 % = double the size), and somatosensory function was checked with tactile stimuli. The pain intensity was rated on a 0-10 Verbal Numerical Rating Scale (VNRS), and sets of psychological questionnaires were completed. HS and LA were associated with significant self-reported perceptual distortions as indicated by consistent increases in perceived size of the adjacent face areas (P ≤ 0.050). Perceptual distortion was most pronounced in the buccal region, and the smallest increase was observed in the auriculotemporal region. HS was associated with moderate levels of pain VNRS = 7.3 ± 0.6. Weak correlations were found between HS-evoked perceptual distortion and level of dissociation in two regions (P < 0.050). Experimental pain and transient sensory deprivation evoked perceptual distortions in all face regions and overall demonstrated the importance of afferent inputs for the perception of the face. We propose that perceptual distortion may be an important phenomenon to consider in persistent orofacial pain conditions.
Conditioned Pain Modulation and Situational Pain Catastrophizing as Preoperative Predictors of Pain following Chest Wall Surgery: A Prospective Observational Cohort Study
Grosen, Kasper; Vase, Lene; Pilegaard, Hans K.; Pfeiffer-Jensen, Mogens; Drewes, Asbjørn M.
Background Variability in patients' postoperative pain experience and response to treatment challenges effective pain management. Variability in pain reflects individual differences in inhibitory pain modulation and psychological sensitivity, which in turn may be clinically relevant for the disposition to acquire pain. The aim of this study was to investigate the effects of conditioned pain modulation and situational pain catastrophizing on postoperative pain and pain persistency. Methods Preoperatively, 42 healthy males undergoing funnel chest surgery completed the Spielberger's State-Trait Anxiety Inventory and Beck's Depression Inventory before undergoing a sequential conditioned pain modulation paradigm. Subsequently, the Pain Catastrophizing Scale was introduced and patients were instructed to reference the conditioning pain while answering. Ratings of movement-evoked pain and consumption of morphine equivalents were obtained during postoperative days 2–5. Pain was reevaluated at six months postoperatively. Results Patients reporting persistent pain at six months follow-up (n = 15) were not significantly different from pain-free patients (n = 16) concerning preoperative conditioned pain modulation response (Z = 1.0, P = 0.3) or level of catastrophizing (Z = 0.4, P = 1.0). In the acute postoperative phase, situational pain catastrophizing predicted movement-evoked pain, independently of anxiety and depression (β = 1.0, P = 0.007) whereas conditioned pain modulation predicted morphine consumption (β = −0.005, P = 0.001). Conclusions Preoperative conditioned pain modulation and situational pain catastrophizing were not associated with the development of persistent postoperative pain following funnel chest repair. Secondary outcome analyses indicated that conditioned pain modulation predicted morphine consumption and situational pain catastrophizing predicted movement-evoked pain intensity in the acute postoperative
Pain in diabetic neuropathy case study: whole patient management.
Marchettini, P; Teloni, L; Formaglio, F; Lacerenza, M
Painful diabetic peripheral neuropathy (DPN) is described as a superficial burning pain associated with other positive and/or negative sensory systems affecting the feet and lower extremities. It is one of the most commonly encountered neuropathic pain syndromes in clinical practice. Presentation may be complicated by multiple symptoms, including allodynia, hyperalgesia, other less well characterized dysesthesias, and serious disruption of social functioning and mood. Peripheral nerve function may deteriorate, which can account for patient reports of diminution of pain after several years of follow-up. Although current understanding holds that the pathogenesis of DPN is multifactorial in nature, long-term studies have shown that rigorous glycemic control is the most relevant factor in clinical intervention and can delay the onset and slow the progression of neuropathy. In addition to glycemic control, other treatment approaches must be examined in order to restore quality of life for patients experiencing painful DPN. Differential diagnosis is required to isolate DPN from other unexplained chronic pain. Neurologic testing in painful DPN is an area of active research and is used to assess the neurologic pathways giving rise to the pain, the degree of neural damage and the degree of subclinical damage. Current treatment options for DPN include mainly antidepressants and anticonvulsants, with other agents such as tramadol, dextromethorphan and memantine being employed or studied. This review article includes a case study of a patient with painful DPN to demonstrate the current management strategies for this neuropathic pain syndrome.
Neurophysiologic studies in congenital insensitivity to pain with anhidrosis.
Shorer, Z; Moses, S W; Hershkovitz, E; Pinsk, V; Levy, J
Thirteen patients with congenital insensitivity to pain and anhidrosis, carrying a mutation at the TRK-A gene, were studied. Neurologic examination revealed vestigial pain sensitivity, suggesting an incomplete involvement of the affected nerves. All 13 patients manifested normal electrophysiologic studies but striking absence of sympathetic skin responses. We suggest the use of the sympathetic skin response test in the clinical evaluation of patients suspected of having congenital insensitivity to pain and anhidrosis.
An Epidemiological Study of Neuropathic Pain Symptoms in Canadian Adults
VanDenKerkhof, Elizabeth G.; Mann, Elizabeth G.; Torrance, Nicola; Smith, Blair H.; Johnson, Ana; Gilron, Ian
The reported prevalence of neuropathic pain ranges from 6.9% to 10%; however the only Canadian study reported 17.9%. The objective of this study was to describe the epidemiology of neuropathic pain in Canada. A cross-sectional survey was conducted in a random sample of Canadian adults. The response rate was 21.1% (1504/7134). Likely or possible neuropathic pain was defined using a neuropathic pain-related diagnosis and a positive outcome on the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs pain scale (S-LANSS) or the Douleur Neuropathique 4 (DN4) Questions. The prevalence of likely neuropathic pain was 1.9% (S-LANSS) and 3.4% (DN4) and that of possible neuropathic pain was 5.8% (S-LANSS) and 8.1% (DN4). Neuropathic pain was highest in economically disadvantaged males. There is a significant burden of neuropathic pain in Canada. The low response rate and a slightly older and less educated sample than the Canadian population may have led to an overestimate of neuropathic pain. Population prevalence varies by screening tool used, indicating more work is needed to develop reliable measures. Population level screening targeted towards high risk groups should improve the sensitivity and specificity of screening, while clinical examination of those with positive screening results will further refine the estimate of prevalence. PMID:27445636
The effects of experimental muscle and skin pain on the static stretch sensitivity of human muscle spindles in relaxed leg muscles
Birznieks, Ingvars; Burton, Alexander R; Macefield, Vaughan G
Animal studies have shown that noxious inputs onto γ-motoneurons can cause an increase in the activity of muscle spindles, and it has been proposed that this causes a fusimotor-driven increase in muscle stiffness that is believed to underlie many chronic pain syndromes. To test whether experimental pain also acts on the fusimotor system in humans, unitary recordings were made from 19 spindle afferents (12 Ia, 7 II) located in the ankle and toe extensors or peronei muscles of awake human subjects. Muscle pain was induced by bolus intramuscular injection of 0.5 ml 5% hypertonic saline into tibialis anterior (TA); skin pain was induced by 0.2 ml injection into the overlying skin. Changes in fusimotor drive to the muscle spindles were inferred from changes in the mean discharge frequency and discharge variability of spindle endings in relaxed muscle. During muscle pain no afferents increased their discharge activity: seven afferents (5 Ia, 2 II) showed a decrease and six (4 Ia, 2 II) afferents were not affected. During skin pain of 13 afferents discharge rate increased in one (Ia) and decreased in two (1 Ia, 1 II). On average, the overall discharge rate decreased during muscle pain by 6.1% (P < 0.05; Wilcoxon), but remained essentially the same during skin pain. There was no detectable correlation between subjective pain level and the small change in discharge rate of muscle spindles. Irrespective of the type of pain, discharge variability parameters were not influenced (P > 0.05; Wilcoxon). We conclude that, contrary to the 'vicious cycle' hypothesis, acute activation of muscle or skin nociceptors does not cause a reflex increase in fusimotor drive in humans. Rather, our results are more aligned with the pain adaptation model, based on clinical studies predicting pain-induced reductions of agonist muscle activity. PMID:18403422
Intensive interdisciplinary outpatient pain management program for chronic back pain: a pilot study
Artner, Juraj; Kurz, Stephan; Cakir, Balkan; Reichel, Heiko; Lattig, Friederike
Background Chronic back pain is relatively resistant to unimodal therapy regimes. The aim of this study was to introduce and evaluate the short-term outcome of a three-week intensive multidisciplinary outpatient program for patients with back pain and sciatica, measured according to decrease of functional impairment and pain. Methods The program was designed for patients suffering from chronic back pain to provide intensive interdisciplinary therapy in an outpatient setting, consisting of interventional injection techniques, medication, exercise therapy, back education, ergotherapy, traction, massage therapy, medical training, transcutaneous electrical nerve stimulation, aquatraining, and relaxation. Results Based on Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) scores, a significant improvement in pain intensity and functionality of 66.83% NRS and an ODI of 33.33% were achieved by our pain program within 3 weeks. Conclusion This paper describes the organization and short-term outcome of an intensive multidisciplinary program for chronic back pain on an outpatient basis provided by our orthopedic department, with clinically significant results. PMID:22826641
North Carolinians Volunteer for Knee Pain Study
... pressure checked, and walk around a track at gyms in central and western North Carolina. Some of ... re looking for ways to reduce pain and improve function and quality of life." What We've ...
Pain Duration and Resolution Following Surgery: An Inception Cohort Study
Carroll, Ian R.; Hah, Jennifer M.; Barelka, Peter L.; Wang, Charlie KM.; Wang, Bing M.; Gillespie, Matthew J.; McCue, Rebecca; Younger, Jarred W.; Trafton, Jodie; Humphreys, Keith; Goodman, Stuart B.; Dirbas, Fredrick M.; Mackey, Sean C.
Objective Preoperative determinants of pain duration following surgery are poorly understood. We identified preoperative predictors of prolonged pain after surgery in a mixed surgical cohort. Methods We conducted a prospective longitudinal study of patients undergoing mastectomy, lumpectomy, thoracotomy, total knee replacement, or total hip replacement. We measured preoperative psychological distress and substance use, and then measured pain and opioid use after surgery until patients reported the cessation of both opioid consumption and pain. The primary endpoint was time to opioid cessation, and those results have been previously reported. Here we report preoperative determinants of time to pain resolution following surgery in Cox proportional hazards regression. Results Between January 2007 and April 2009 we enrolled 107 of 134 consecutively approached patients undergoing the aforementioned surgical procedures. In the final multivariate model, preoperative self-perceived risk of addiction predicted more prolonged pain. Unexpectedly, anxiety sensitivity predicted more rapid pain resolution after surgery. Each one-point increase (on a four point scale) of self-perceived risk of addiction was associated with a 38% (95% CI 3 - 61) reduction in the rate of pain resolution (p= 0.04). Furthermore, higher anxiety sensitivity was associated with an 89% (95% CI 23–190) increased rate of pain resolution (p=0.004). Conclusions Greater preoperative self-perceived risk of addiction, and lower anxiety sensitivity predicted a slower rate of pain resolution following surgery. Each of these factors was a better predictor of pain duration than preoperative depressive symptoms, PTSD symptoms, past substance use, fear of pain, gender, age, preoperative pain, or preoperative opioid use. PMID:26179223
Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron
Hedenberg-Magnusson, Britt; List, Thomas; Svensson, Peter; Schalling, Martin
The aim of this study was to investigate experimentally if 5-HT3 single nucleotide polymorphisms (SNP) contribute to pain perception and efficacy of the 5-HT3-antagonist granisetron and sex differences. Sixty healthy participants were genotyped regarding HTR3A (rs1062613) and HTR3B (rs1176744). First, pain was induced by bilateral hypertonic saline injections (HS, 5.5%, 0.2 mL) into the masseter muscles. Thirty min later the masseter muscle on one side was pretreated with 0.5 mL granisetron (1 mg/mL) and on the other side with 0.5 mL placebo (isotonic saline) followed by another HS injection (0.2 mL). Pain intensity, pain duration, pain area and pressure pain thresholds (PPTs) were assessed after each injection. HS evoked moderate pain, with higher intensity in the women (P = 0.023), but had no effect on PPTs. None of the SNPs influenced any pain variable in general, but compared to men, the pain area was larger in women carrying the C/C (HTR3A) (P = 0.015) and pain intensity higher in women with the A/C alleles (HTR3B) (P = 0.019). Pre-treatment with granisetron reduced pain intensity, duration and area to a lesser degree in women (P < 0.05), but the SNPs did not in general influence the efficacy of granisetron. Women carrying the C/T & T/T (HTR3A) genotype had less reduction of pain intensity (P = 0.041) and area (P = 0.005), and women with the C/C genotype (HTR3B) had less reduction of pain intensity (P = 0.030), duration (P = 0.030) and area compared to men (P = 0.017). In conclusion, SNPs did not influence experimental muscle pain or the effect of granisetron on pain variables in general, but there were some sex differences in pain variables that seem to be influenced by genotypes. However, due to the small sample size further research is needed before any firm conclusions can be drawn. PMID:28002447
Experimental Muscle Pain Impairs the Synergistic Modular Control of Neck Muscles.
Gizzi, Leonardo; Muceli, Silvia; Petzke, Frank; Falla, Deborah
A motor task can be performed via different patterns of muscle activation that show regularities that can be factorized in combinations of a reduced number of muscle groupings (also referred to as motor modules, or muscle synergies). In this study we evaluate whether an acute noxious stimulus induces a change in the way motor modules are combined to generate movement by neck muscles. The neck region was selected as it is a region with potentially high muscular redundancy. We used the motor modules framework to assess the redistribution of muscular activity of 12 muscles (6 per side) in the neck region of 8 healthy individuals engaged in a head and neck aiming task, in non-painful conditions (baseline, isotonic saline injection, post pain) and after the injection of hypertonic saline into the right splenius capitis muscle. The kinematics of the task was similar in the painful and control conditions. A general decrease of activity was noted for the injected muscle during the painful condition together with an increase or decrease of the activity of the other muscles. Subjects did not adopt shared control strategies (motor modules inter subject similarity at baseline 0.73±0.14); the motor modules recorded during the painful condition could not be used to reconstruct the activation patterns of the control conditions, and the painful stimulus triggered a subject-specific redistribution of muscular activation (i.e., in some subjects the activity of a given muscle increased, whereas in other subjects it decreased with pain). Alterations of afferent input (i.e., painful stimulus) influenced motor control at a multi muscular level, but not kinematic output. These findings provide new insights into the motor adaptation to pain.
Osteoarthritis pain mechanisms: Basic studies in animal models
Zhang, Rui-Xin; Ren, Ke; Dubner, Ronald
Osteoarthritis (OA) is a complex and painful disease of the whole joint. At present there are no satisfying agents for treating OA. The current standard of care mainly involves managing and alleviating its symptoms. Mechanisms of OA pain have been studied in rodent knee OA models produced by intra-knee injection of the chondrocyte glycolytic inhibitor mono-iodoacetate, surgery, or spontaneous development in some species. These models are clinically relevant in terms of histological damage and functional changes, and are used to study mechanisms underlying mechanical, thermal, ambulatory, body weight supporting-evoked, and ongoing OA pain. Recent peripheral, spinal, and supraspinal biochemical and electrophysiological studies in these models suggest that peripheral pro-inflammatory mediators and neuropeptides sensitize knee nociceptors. Spinal cytokines and neuropeptides promote OA-associated pain, and peripheral and spinal cannabinoids inhibit OA pain respectively through cannabinoid-1 (CB1) and CB1/CB2 receptors. TRPV1 and metalloproteinases contribute and supraspinal descending facilitation of 5-HT/5-HT 3 receptors may also contribute to OA pain. Conditioned place preference tests demonstrate that OA pain induces aversive behaviors suggesting brain involvement in OA pain. During OA, brain functional connectivity is enhanced, but at present it is unclear how this change is related to OA pain. PMID:23973145
Experimental muscle pain decreases the frequency threshold of electrically elicited muscle cramps.
Serrao, Mariano; Arendt-Nielsen, Lars; Ge, Hong-You; Pierelli, Francesco; Sandrini, Giorgio; Farina, Dario
This study in humans tested the hypothesis that nociceptive muscle afferent input facilitates the occurrence of muscle cramps. In 13 healthy adults, muscle cramps were experimentally induced in the foot by stimulating the tibialis posterior nerve at the ankle with 2-s bursts of stimuli separated by 30 s, with stimulation frequency increasing by 2-Hz increments from 10 Hz until the cramp appeared. The minimum stimulation frequency that induced the cramp was defined "cramp frequency threshold". In 2 days, elicitation of the cramp was performed in the two-feet with and without (baseline condition) injection of hypertonic (painful condition) or isotonic (control condition) saline into the deep midportion of the flexor hallucis brevis muscle, from where surface EMG signals were recorded. The cramp frequency threshold was lower for the painful condition with respect to its baseline (mean +/- SE, hypertonic saline: 25.7 +/- 2.1 Hz, corresponding baseline: 31.2 +/- 2.8 Hz; P < 0.01) while there was no difference between the threshold with isotonic injection with respect to baseline. EMG average rectified value and power spectral frequency were higher during the cramp than immediately before the stimulation that elicited the cramp (pre-cramp: 13.9 +/- 1.6 muV and 75.4 +/- 3.8 Hz, respectively; post-cramp: 19.9 +/- 3.2 muV and 101.6 +/- 6.0 Hz; P < 0.05). The results suggest that nociceptive muscle afferent activity induced by injection of hypertonic saline facilitates the generation of electrically elicited muscle cramps.
Acute effect of Aloe vera gel extract on experimental models of pain.
Rathor, Naveen; Mehta, Ashish K; Sharma, Amit K; Mediratta, Pramod K; Sharma, Krishna K
The present study was performed to explore the effect of aqueous extract of Aloe vera on behavioural parameters of pain. Pain assessment was performed by the tail-flick and formalin tests. A. vera (100 mg/kg, per oral (p.o.)) produced an insignificant decrease in the pain response in the tail-flick and formalin tests. Moreover, A. vera (200 and 400 mg/kg, p.o.) did not have significant effect on the tail-flick test. However, A. vera (200 and 400 mg/kg, p.o.) significantly decreased the second phase of the formalin-induced pain. Thus, these findings suggest that A. vera exerts its effect by a peripheral mechanism of action rather than central.
Toll-like Receptor 4 and Comorbid Pain in Interstitial Cystitis/Bladder Pain Syndrome: A Multidisciplinary Approach to the Study of Chronic Pelvic Pain Research Network Study
Schrepf, Andrew; Bradley, Catherine S.; O'Donnell, Michael; Luo, Yi; Harte, Steven E.; Kreder, Karl; Lutgendorf, Susan
Background Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a condition characterized by pelvic pain and urinary symptoms. Some IC/BPS patients have pain confined to the pelvic region, while others suffer widespread pain. Inflammatory processes have previously been linked to pelvic pain in IC/BPS, but their association with widespread pain in IC/BPS has not been characterized. Methods Sixty-six women meeting criteria for IC/BPS completed self-report measures of pain as part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP), collected 3 days of saliva for cortisol assays, and provided blood samples. Peripheral blood mononuclear cells (PBMCs) were stimulated with Toll-Like Receptor (TLR) 2 and 4 agonists and cytokines were measured in supernatant; IL-6 was also measured in plasma. Associations between inflammatory variables and the likelihood of endorsing extra-pelvic pain, or the presence of a comorbid syndrome, were tested by logistic regression and General Linear Models, respectively. A subset of patients (n=32) completed Quantitative Sensory Testing. Results A one standard deviation increase in TLR-4 inflammatory response was associated with a 1.59 greater likelihood of endorsing extra-pelvic pain (p = .019). Participants with comorbid syndromes also had higher inflammatory responses to TLR-4 stimulation in PBMCs (p = .016). Lower pressure pain thresholds were marginally associated with higher TLR-4 inflammatory responses (p = .062), and significantly associated with higher IL-6 in plasma (p = .031). Conclusions TLR-4 inflammatory responses in PBMCs are a marker of widespread pain in IC/BPS, and should be explored in other conditions characterized by medically unexplained pain. PMID:25771510
Influence of topical capsaicin on facial sensitivity in response to experimental pain.
Lee, Y-S; Kho, H-S; Kim, Y-K; Chung, S-C
Capsaicin, the pungent component of the red pepper, has been used as an analgesic in a variety of pain conditions, but sensory impairment after long-term treatment has been concerned. This study investigated the influence of topical capsaicin on various types of sensations including pain in the facial areas innervated by the mental nerve, and also evaluated whether the measurement of cutaneous current perception threshold (CPT) is reliable for the quantification of sensory change following capsaicin application. Twenty healthy subjects were given topical capsaicin cream (0.075%), which was applied to the mental area unilaterally, four times daily for 2 weeks. Burning sensation after capsaicin application gradually decreased with repeated applications. Repeated topical capsaicin resulted in reduced sensation to mechanical, heat and cold pain without changing non-painful tactile sensation. It also resulted in increased CPTs at 5 Hz and 250 Hz stimuli but no change in the CPTs at 2000 Hz from the first evaluation after capsaicin treatment and throughout the treatment period. This study demonstrated that topical capsaicin treatment for the management of chronic localized pain can be safely applied to the face without affecting non-painful normal sensations, and that CPT testing is a clinically useful tool for the quantification of sensory changes following capsaicin application.
The Haglund painful heel syndrome. Experimental investigation of cause and therapeutic implications.
Heneghan, M A; Pavlov, H
Haglund syndrome, a common cause of pain in the posterior heel, consists of a painful swelling of the local soft tissues (the so-called pump bump) and prominence of the calcaneal bursal projection. The condition is caused by compression of the distal Achilles tendon and surrounding soft tissue between the os calcis and the posterior shoe counter. Osseous plantar projections appear to be a critical etiologic factor in Haglund syndrome. With an experimental model, it has been demonstrated that osseous projections on the plantar surface of the calcaneus adversely influence the bone-soft tissue relation of the posterior heel. Shoe heel elevation has been shown to be clinically effective in alleviating symptoms. It is demonstrated with an experimental model that elevation of the shoe heel decreases the pitch angle. This diminishes the prominence of the bursal projection and allows the foot to slip forward, displacing the posterior calcaneus away from the shoe counter.
Effect of muscle relaxants on experimental jaw-muscle pain and jaw-stretch reflexes: a double-blind and placebo-controlled trial.
Svensson, Peter; Wang, Kelun; Arendt-Nielsen, Lars
A randomised, double-blind, placebo-controlled three-way cross-over study was performed to investigate the effect of two muscle relaxants (tolperisone hydrochloride and pridinol mesilate) on experimental jaw-muscle pain and jaw-stretch reflexes. Fifteen healthy men participated in three randomised sessions separated by at least 1 week. In each session 300 mg tolperisone, 8 mg pridinol mesilate or placebo was administered orally as a single dose. One hour after drug administration 0.3 ml hypertonic saline (5.8%) was injected into the right masseter to produce muscle pain. Subjects continuously rated their perceived pain intensity on an electronic 10-cm visual analogue scale (VAS). The pressure pain threshold (PPT) was measured and short-latency reflex responses were evoked in the pre-contracted (15% maximal voluntary contraction) masseter and temporalis muscles by a standardised stretch device (1 mm displacement, 10 ms ramp time) before (baseline), 1 h after medication (post-drug), during ongoing experimental muscle pain (pain-post-drug), and 15 min after pain had vanished (post-pain). Analysis of variance demonstrated significantly lower VAS peak pain scores (5.9 +/- 0.4 cm) after administration of tolperisone hydrochloride compared with pridinol mesilate (6.8 +/- 0.4 cm) and placebo (6.6 +/- 0.4 cm) (P=0.020). Administration of pridinol mesilate was associated with a significant decrease in PPTs compared with tolperisone hydrochloride and placebo (P=0.002) after medication, but not after experimental jaw-muscle pain. The normalised peak-to-peak amplitude of the stretch reflexes were not significantly influenced by the test medication (P=0.762), but were in all sessions significantly facilitated during ongoing experimental jaw-muscle pain (P=0.034). In conclusion, tolperisone hydrochloride provides a small, albeit significant reduction in the perceived intensity of experimental jaw-muscle pain whereas the present dose had no effect on the short-latency jaw
Pregabalin in post traumatic neuropathic pain: Case studies
Singh, Rakesh Kumar; Sinha, Vijay Prakash; Pal, U. S.; Yadav, Sharad C.; Singh, Maneesh K.
Pregabalin is effective in the treatment of peripheral and central neuropathic pain. This study evaluated the effectiveness of pregablin in management of post traumatic peripheral nerve injury facial pain not responding to other medication like analgesics. Pregabalin was well tolerated. The most common adverse effects were dizziness and tiredness. PMID:23251069
Pain and anxiety control: an online study guide.
The Editorial Board of the Journal of Endodontics has developed a literature-based study guide of topical areas related to endodontics. This study guide is intended to give the reader a focused review of the essential endodontic literature and does not cite all possible articles related to each topic. Although citing all articles would be comprehensive, it would defeat the idea of a study guide. This section will cover pain theories and dentin hypersensitivity, referred pain, oral pain not of dental origin, barodontalgia, local anesthetics, long-acting local anesthetics, intrapulpal anesthesia, intraligamentary anesthesia, intraosseous anesthesia, inferior alveolar nerve block anesthesia, Gow-Gates anesthesia technique, Vazirani-Akinosi anesthesia technique, second-division block anesthesia technique, endodontic postoperative pain, effect of occlusal adjustment on endodontic pain, paresthesia associated with periradicular pathosis, analgesics, sedation, and endodontic flare-ups.
Wolf, Elizabeth Pauline
1. Wright's method for the study of chemotaxis of leucocytes in vitro, slightly modified, has been found to be most satisfactory in the estimation of the degree of chemotaxis of various substances, because it is possible to make an exact quantitative determination of the leucocytes that have migrated from the blood clot and adhere to the surfaces containing the tested substance. 2. The calcium ion is the only inorganic ion per se which is found to be positively chemotactic under the conditions of these experiments. It is markedly chemotactic in all concentrations and in all combinations, except the citrate. Here the negative chemotaxis of the citrate ion neutralizes the positive chemotaxis of the calcium ion, and neutrality of chemotactic effect results. 3. The sodium and magnesium ions themselves are neutral. Magnesium and sodium salts are dependent upon the negative ion with which the magnesium or sodium is combined for such positive or negative chemotaxis as is exhibited. All the phosphates of sodium, whether tri-, di-, or monobasic salts, are markedly positively chemotactic, and when combined with other reagents which are themselves neutral or negatively chemotactic, produce marked positive chemotaxis. The blood of a person who has taken phosphates either by mouth or intravenously shows a great increase in chemotaxis with sodium phosphate, with calcium chloride, and even with sodium chloride which is ordinarily neutral. 4. All potassium salts are negatively chemotactic. 5. Many substances act synergistically as regards chemotaxis; e.g., when strontium and magnesium salts are mixed there is a marked increase in chemotaxis. Sodium phosphate acts synergistically with calcium chloride. 6. Mercury salts fix the leucocytes in this method so that their influence on chemotaxis cannot be determined. 7. Morphine and morphine salts are positively chemotactic; this is contrary to the results obtained by others with different methods. 8. Substances which produce a very
Manipulating the Placebo Response in Experimental Pain by Altering Doctor's Performance Style
Czerniak, Efrat; Biegon, Anat; Ziv, Amitai; Karnieli-Miller, Orit; Weiser, Mark; Alon, Uri; Citron, Atay
Background: Performance is paramount in traditional healing rituals. From a Western perspective, such performative behavior can be understood principally as inducing patients' faith in the performer's supernatural healing powers and effecting positive changes through the same mechanisms attributed to the placebo response, which is defined as improvement of clinical outcome in individuals receiving inactive treatment. Here we examined the possibility of using theatrical performance tools, including stage directions and scripting, to reproducibly manipulate the style and content of a simulated doctor–patient encounter and influence the placebo response in experimental pain. Methods: A total of 122 healthy volunteers (18–45 years, 76 men) exposed to experimental pain (the cold pressor test) were assessed for pain threshold and tolerance before and after receiving a placebo cream from a "doctor" impersonated by a trained actor. The actor alternated between two distinct scripts and stage directions, i.e., performance styles created by a theater director/playwright, one emulating a standard doctor–patient encounter (scenario A) and the other emphasizing attentiveness and strong suggestion, elements also present in ritual healing (scenario B). The placebo response size was calculated as the %difference in pain threshold and tolerance after exposure relative to baseline. In addition, subjects demonstrating a ≥30% increase in pain threshold or tolerance relative to baseline were defined as responders. Each encounter was videotaped in its entirety. Results: Inspection of the videotapes confirmed the reproducibility and consistency of the distinct scenarios enacted by the "doctor"-performer. Furthermore, scenario B resulted in a significant increase in pain threshold relative to scenario A. Interestingly, this increase derived from the placebo responder subgroup; as shown by two-way analysis of variance (performance style, F = 4.30; p = 0.040; η2 = 0
Efficacy and safety of PPC-5650 on experimental rectal pain in patients with irritable bowel syndrome.
Nielsen, Lecia Møller; Olesen, Anne Estrup; Andresen, Trine; Simrén, Magnus; Törnblom, Hans; Drewes, Asbjørn Mohr
PPC-5650 is a new pharmacological agent that can modulate acid-sensing ion channel activity, leading to a reduction in the pain signal under up-regulated conditions. The non-clinical programme for PPC-5650 supported a role for this novel agent in the treatment of pain in patients with irritable bowel syndrome (IBS). In patients with IBS, the aims of the study were: (1) to assess the efficacy of a single bolus of PPC-5650 locally applied in the rectum using multi-modal stimulations of the recto sigmoid and (2) to assess the safety profile of PPC-5650. The study was a randomized, double-blind, placebo-controlled, cross-over trial in patients with IBS, excluding females of child-bearing potential. The study consisted of a training visit, study visit 1 and 2 and a follow-up visit. Rectosigmoid electrical, thermal and mechanical stimulations were performed, pain perception was rated on a pain intensity scale and referred pain areas were assessed. All adverse events were registered. Twenty-five patients with IBS were enrolled and completed the study (9 women and 16 men; mean age 50.4 ± 12.7 years). No effects of the study drug were found on any of the rectal stimulations or for referred pain areas (all p > 0.05). No significant or clinically relevant treatment-related differences were seen for the laboratory safety variables or any other reported adverse event. In conclusion, in patients with IBS on rectal sensitivity to multi-modal stimulations, PPC-5650 did not produce efficacy relative to placebo. The overall safety and tolerability of PPC-5650 was acceptable.
[Postoperative pain therapy in urology. A prospective study].
Gronau, E; Pannek, J; Benninghoff, A; Seibold, W; Senge, T
A sufficient analgesic treatment in the early postoperative period is important for the patients comfort level. Moreover, physical therapy for prophylaxis of pneumonia and thrombosis is better tolerated. In a prospective study, we compared two postoperative pain management regimens to establish a sufficient pain management without the need of additional costs or manpower. Of 215 patients undergoing major urologic surgery, 111 patients received on demand medication exclusively (group 1), whereas 104 patients were treated with basic analgesics combined with on demand medication (group 2). Pain intensity, side effects and subjective well being were evaluated with a visual analogue scale and a standardised interview. Pain intensity and side effects were significantly lower in group 2. Thus, with combined analgesic treatment, postoperative pain relieve can be achieved safely and without additional costs.
Influence of exercise on visceral pain: an explorative study in healthy volunteers
van Weerdenburg, Laura JGM; Brock, Christina; Drewes, Asbjørn Mohr; van Goor, Harry; de Vries, Marjan; Wilder-Smith, Oliver HG
Background and objectives Contradictory results have been found about the effect of different exercise modalities on pain. The aim of this study was to investigate the early effects of aerobic and isometric exercise on different types of experimental pain, including visceral pain, compared to an active control condition. Methods Fifteen healthy subjects (6 women, mean [standard deviation] age 25 [6.5] years) completed 3 interventions consisting of 20 minutes of aerobic cycling, 12 minutes of isometric knee extension and a deep breathing procedure as active control. At baseline and after each intervention, psychophysical tests were performed, including electrical stimulation of the esophagus, pressure pain thresholds and the cold pressor test as a measure for conditioned pain modulation. Participants completed the Medical Outcome Study Short-Form 36 and State-Trait Anxiety Inventory prior to the experiments. Data were analyzed using two-way repeated measures analysis of variance. Results No significant differences were found for the psychophysical tests after the interventions, compared to baseline pain tests and the control condition. Conclusion No hypoalgesic effect of aerobic and isometric exercise was found. The evidence for exercise-induced hypoalgesia appears to be not as consistent as initially thought, and caution is recommended when interpreting the effects of exercise on pain. PMID:28096689
A Clinical Experimental Model to Evaluate Analgesic Effect of Remote Ischemic Preconditioning in Acute Postoperative Pain
Pereira, Francisco Elano Carvalho; Mello, Irene Lopes; Pimenta, Fernando Heladio de Oliveira Medeiros; Costa, Debora Maia; Wong, Deysi Viviana Tenazoa; Fernandes, Claudia Regina; Lima Junior, Roberto César; Gomes, Josenília M. Alves
This study aims to evaluate the viability of a clinical model of remote ischemic preconditioning (RIPC) and its analgesic effects. It is a prospective study with twenty (20) patients randomly divided into two groups: control group and RIPC group. The opioid analgesics consumption in the postoperative period, the presence of secondary mechanical hyperalgesia, the scores of postoperative pain by visual analog scale, and the plasma levels interleukins (IL-6) were evaluated. The tourniquet applying after spinal anesthetic block was safe, producing no pain for all patients in the tourniquet group. The total dose of morphine consumption in 24 hours was significantly lower in RIPC group than in the control group (p = 0.0156). The intensity analysis of rest pain, pain during coughing and pain in deep breathing, showed that visual analogue scale (VAS) scores were significantly lower in RIPC group compared to the control group: p = 0.0087, 0.0119, and 0.0015, respectively. There were no differences between groups in the analysis of presence or absence of mechanical hyperalgesia (p = 0.0704) and in the serum levels of IL-6 dosage over time (p < 0.0001). This clinical model of remote ischemic preconditioning promoted satisfactory analgesia in patients undergoing conventional cholecystectomy, without changing serum levels of IL-6. PMID:27446611
Acupuncture for low back pain due to spondylolisthesis: study protocol for a randomized controlled pilot trial
Background Spondylolisthesis is the major cause of refractory low back pain. There are many studies of the surgical treatment of spondylolisthesis, but few of conservative treatments. There is also no optimal conservative treatment protocol, however, low back pain caused by low-grade spondylolisthesis is controlled with non-surgical pain management. Acupuncture has become a useful method for treating low back pain, but there has not been any study of its efficacy in relation to spondylolisthesis. This study was designed to establish the feasibility of a randomized controlled trial and the safety of acupuncture for low back pain due to low-grade spondylolisthesis. Methods/Design The study is a randomized controlled pilot clinical trial of five weeks duration. Fourteen patients will be recruited and randomly allocated to two groups: an acupuncture plus interlaminar epidural steroid injection group (experimental group), and an interlaminar epidural steroid injection group (control group). All patients will be administered an interlaminar epidural steroid injection once a week for three weeks (three injections in total), but only the experimental group will receive additional treatment with three acupuncture sessions a week for three weeks (nine acupuncture sessions in total). The primary outcome will be measured by the visual analogue scale (VAS). Our primary end point is three-week VAS. The secondary outcome will be measured using the PainVision system, the short-form McGill Pain Questionnaire, and the Oswestry Disability Index. Assessments will be made at baseline and at one, three and five weeks thereafter (that is, the five-week assessment will be made two weeks after treatment cessation). Discussion This randomized controlled pilot trial will inform the design of a further full-scale trial. The outcomes will provide some resources for incorporating acupuncture into existing pain management methods such as interlaminar epidural steroid injection in low
A review of the epidemiology of painful diabetic peripheral neuropathy, postherpetic neuralgia, and less commonly studied neuropathic pain conditions.
Sadosky, Alesia; McDermott, Anne M; Brandenburg, Nancy A; Strauss, Marcie
Although the burden of neuropathic pain is well-recognized, the descriptive epidemiology of specific neuropathic pain conditions has not been well-described. While painful diabetic peripheral neuropathy and postherpetic neuralgia have been widely evaluated, many other peripheral and central neuropathic pain syndromes have been less frequently studied. This review summarizes incidence and/or prevalence information about two relatively frequent neuropathic pain conditions-painful diabetic peripheral neuropathy and postherpetic neuralgia-and similarly summarizes the more limited epidemiologic information available for other peripheral and central neuropathic pain conditions. The data suggest that while our knowledge is still incomplete, the high frequency of several of these conditions in specific populations should be considered an important impetus for further studies designed to evaluate their contribution to the overall burden of neuropathic pain.
Experimental studies: randomized clinical trials.
Gjorgov, A N
There are two major approaches to medical investigations: observational studies and experimental trials. The classical application of the experimental design to studies of human populations is the randomized clinical trial of the efficacy of a new drug or treatment. A further application of the experimental studies is to the testing of hypotheses about the etiology of a disease, already tested and corroborated from various forms of observational studies. Ethical considerations and requirements for consent of the experimental subjects are of primary concern in the clinical trials, and those concerns set the first and final limits for implementing a trial. General moral principles in research with human and animal beings, defined by the "Nuremberg Code," deal with strict criteria for approval, endorsement and evaluation of a clinical trial.
Space Adaptation Back Pain: A Retrospective Study
NASA Technical Reports Server (NTRS)
Kerstman, Eric
Astronaut back pain is frequently reported in the early phase of space flight as they adapt to microgravity. The epidemiology of space adaptation back pain (SABP) has not been well established. This presentation seeks to determine the exact incidence of SABP among astronauts, develop a case definition of SABP, delineate the nature and pattern of SABP, review available treatments and their effectiveness in relieving SABP; and identify any operational impact of SABP. A retrospective review of all available mission medical records of astronauts in the U.S. space program was performed. It was revealed that the incidence of SABP has been determined to be 53% among astronauts in the U.S. space program; most cases of SABP are mild, self-limited, or respond to available treatment; there are no currently accepted preventive measures for SABP; it is difficult to predict who will develop SABP; the precise mechanism and spinal structures responsible for SABP are uncertain; there was no documented evidence of direction operational mission impact related to SABP; and, that there was the potential for mission impact related to uncontrolled pain, sleep disturbance, or the adverse side effects pf anti-inflammatory medications
Entrapment of adult fingers between window glass and seal entry of a motor vehicle side door: an experimental study for investigation of the force at the subjective pain threshold.
Hohendorff, B; Weidermann, C; Pollinger, P; Burkhart, K J; Konerding, M A; Prommersberger, K J; Rommens, P M
In modern motor vehicles with automatic power windows, a potential hazard exists for jam events of fingers between the window glass and seal entry. This study determined entrapment forces acting on adult fingers at the subjective maximum pain threshold during entrapment in such windows. The length and the girth of the proximal and distal interphalangeal joints of the triphalangeal fingers of the right hands of 109 participants (60 men, 49 women) were measured; the diameter was calculated from girth, which was assumed to be circular. The automatic power window system of a motor vehicle side door was changed to a mechanical system. During entrapment the force distributed across the four proximal interphalangeal joints (PIPs), and separately on the proximal interphalangeal (iPIP) and then the distal interphalangeal (iDIP) joints of the index finger was measured using a customized force sensor. The maximum bearable entrapment force was 97.2 ± 51.8 N for the PIPs, 43.4 ± 19.9 N for the iPIP, and 36.9 ± 17.8 N for the iDIP. The positive correlation between finger diameter and maximum entrapment force was significant. Particularly with regard to the risk to children's fingers, the 100 N statutory boundary value for closing force of electronic power windows should be reduced.
Serum vitamin C and spinal pain: a nationwide study.
Dionne, Clermont E; Laurin, Danielle; Desrosiers, Thérèse; Abdous, Belkacem; Le Sage, Natalie; Frenette, Jérôme; Mondor, Myrto; Pelletier, Sylvie
Back pain brings about one of the heaviest burden of disease. Despite much research, this condition remains poorly understood, and effective treatments are frustratingly elusive. Thus, researchers in the field need to consider new hypotheses. Vitamin C (ascorbic acid) is an essential cofactor for collagen crosslinks, a key determinant of ligament, tendon, and bone quality. Recent studies have reported high frequency of hypovitaminosis C in the general population. We hypothesized that lack of vitamin C contributes to poor collagen properties and back pain. We conducted this study to examine the associations between serum concentration of vitamin C and the prevalence of spinal pain and related functional limitations in the adult general population. This study used nationwide cross-sectional data from the U.S. National Health and Nutrition Examination Survey (NHANES) 2003-2004. Data were available for 4742 individuals aged ≥20 years. Suboptimal serum vitamin C concentrations were associated with the prevalence of neck pain (adjusted odds ratio [aOR]: 1.5; 95% confidence interval [CI]: 1.2-2.0), low back pain (aOR: 1.3; 95% CI: 1.0-1.6), and low back pain with pain below knee (aOR: 1.3; 95% CI: 1.0-1.9) in the past 3 months, self-reported diagnosis of arthritis/rheumatism (aOR: 1.4; 95% CI: 1.2-1.7), and related functional limitations' score (adjusted difference of means [aB]: 0.03; 95% CI: 0.00-0.05). The prevalence of hypovitaminosis C in the general population is high. Our study shows associations between vitamin C and spinal pain that warrant further investigation to determine the possible importance of vitamin C in the treatment of back pain patients.
Effects of LLLT for pain: a clinical study on different pain types
NASA Astrophysics Data System (ADS)
Tam, Giuseppe
Objective: The aim of this clinical study is to determine the efficacy of the JR diode laser 904 nm pulsed on pain reduction therapy. Summary Background Data: With respect to pain, the existence of a filter (Rolando's substantia gelatinosa) in the spinal marrow is fundamental. Opening or closing, this filter is able to block transmission of pain impulses to a higher cerebral center. This is in proportion with the A big fibres and C small fibres. The action of the laser influences this mechanism. Additionally, laser interferes in the cytochines (TNf-α , interleukin-1 and interleukin-6) that drive inflammation in the arthritis and are secreted from CD4 e T cells. Low power density laser increases the endorphin synthesis in the dorsal posterior horn of the spinal cord. Besides, laser causes local vasodilatation of the capillaries and an improved circulation of drainage liquids in interstitial space causing an analgesic effect. Methods: Treatment was carried out on 482 cases and 464 patients (274 women and 190 men) in the period between 1987 and 2000. The patients, whose age ranged from 25 to 70, with a mean age of 45 years, were suffering from rheumatic, degenerative and traumatic pathologies as well as cutaneous ulcers. The majority of the patients had been seen by orthopaedists and rheumatologists and had undergone x-ray, ultrasound scanning, TAC, RM examination. All patients had previously received drug-based treatment and/or physiotherapy with poor results. Two thirds were experiencing acute symptomatic pain, while the others presented a chronic pathology with recurrent crises. We used a pulsed JR diode laser, GaAs 904 nm wavelength. Results: Jn the evaluation of the results the following parameters have been considered: disappearance of spontaneous and induced pain, anatomic and functional evaluation of the joints, muscular growth, verbal rating scales, hand dinamometer, patient's pain diary. Very good results were achieved especially with cases of symptomatic
Pain assessment in animal models: do we need further studies?
Gigliuto, Carmelo; De Gregori, Manuela; Malafoglia, Valentina; Raffaeli, William; Compagnone, Christian; Visai, Livia; Petrini, Paola; Avanzini, Maria Antonietta; Muscoli, Carolina; Viganò, Jacopo; Calabrese, Francesco; Dominioni, Tommaso; Allegri, Massimo; Cobianchi, Lorenzo
In the last two decades, animal models have become important tools in understanding and treating pain, and in predicting analgesic efficacy. Although rodent models retain a dominant role in the study of pain mechanisms, large animal models may predict human biology and pharmacology in certain pain conditions more accurately. Taking into consideration the anatomical and physiological characteristics common to man and pigs (median body size, digestive apparatus, number, size, distribution and communication of vessels in dermal skin, epidermal-dermal junctions, the immunoreactivity of peptide nerve fibers, distribution of nociceptive and non-nociceptive fiber classes, and changes in axonal excitability), swines seem to provide the most suitable animal model for pain assessment. Locomotor function, clinical signs, and measurements (respiratory rate, heart rate, blood pressure, temperature, electromyography), behavior (bright/quiet, alert, responsive, depressed, unresponsive), plasma concentration of substance P and cortisol, vocalization, lameness, and axon reflex vasodilatation by laser Doppler imaging have been used to assess pain, but none of these evaluations have proved entirely satisfactory. It is necessary to identify new methods for evaluating pain in large animals (particularly pigs), because of their similarities to humans. This could lead to improved assessment of pain and improved analgesic treatment for both humans and laboratory animals.
Pain assessment in animal models: do we need further studies?
Gigliuto, Carmelo; De Gregori, Manuela; Malafoglia, Valentina; Raffaeli, William; Compagnone, Christian; Visai, Livia; Petrini, Paola; Avanzini, Maria Antonietta; Muscoli, Carolina; Viganò, Jacopo; Calabrese, Francesco; Dominioni, Tommaso; Allegri, Massimo; Cobianchi, Lorenzo
In the last two decades, animal models have become important tools in understanding and treating pain, and in predicting analgesic efficacy. Although rodent models retain a dominant role in the study of pain mechanisms, large animal models may predict human biology and pharmacology in certain pain conditions more accurately. Taking into consideration the anatomical and physiological characteristics common to man and pigs (median body size, digestive apparatus, number, size, distribution and communication of vessels in dermal skin, epidermal–dermal junctions, the immunoreactivity of peptide nerve fibers, distribution of nociceptive and non-nociceptive fiber classes, and changes in axonal excitability), swines seem to provide the most suitable animal model for pain assessment. Locomotor function, clinical signs, and measurements (respiratory rate, heart rate, blood pressure, temperature, electromyography), behavior (bright/quiet, alert, responsive, depressed, unresponsive), plasma concentration of substance P and cortisol, vocalization, lameness, and axon reflex vasodilatation by laser Doppler imaging have been used to assess pain, but none of these evaluations have proved entirely satisfactory. It is necessary to identify new methods for evaluating pain in large animals (particularly pigs), because of their similarities to humans. This could lead to improved assessment of pain and improved analgesic treatment for both humans and laboratory animals. PMID:24855386
Pain education issues in developing countries and responses to them by the International Association for the Study of Pain.
Bond, Michael
Unrelieved pain remains a global health problem. There is a major difference between what could be done to relieve pain and what is being done in developing countries - this is known as the 'treatment gap'. Poor education of health professionals, limited facilities for pain treatment and poor access to drugs for pain relief are contributing factors. While enthusiasm for pain education and clinical training in developing countries has grown, restrictions by governments and health administrations have represented a significant barrier to practice changes. Since 2002, the International Association for the Study of Pain, through its Developing Countries Working Group, has established a series of programs that have resulted in significant improvements in pain education and the clinical management of pain, together with the beginnings of a system of pain centres. These pain centres will act as regional hubs for the future expansion of education and training in pain management in developing countries. Further success will be increased with the demolition of barriers to the treatment of people in pain worldwide.
The effects of failure feedback and pain-related fear on pain report, pain tolerance, and pain avoidance in chronic low back pain patients.
van den Hout, J H; Vlaeyen, J W; Houben, R M; Soeters, A P; Peters, M L
The aim of this study was to investigate the influence of non-pain-related failure experiences and pain-related fear on pain report, pain tolerance and pain avoidance in chronic low back pain (CLBP) patients. Moreover, the mediating and moderating role of negative affectivity (trait-NA) in the relationship between failure experiences and pain was examined. Seventy-six patients were divided into high and low pain-related fear groups and within each group they were randomly assigned to the failure or success feedback condition. In the first part of the study patients completed a 'social empathy test' and experimenter 1 subsequently delivered false failure or success feedback. A second experimenter, who was blind for the condition, subsequently administered two lifting tasks in order to obtain measures of pain report, tolerance and avoidance. Failure feedback did have an effect on pain avoidance but unexpectedly, and not as hypothesized, pain avoidance was reduced instead of enhanced. With regard to pain report and pain tolerance similar patterns were found, but these were not statistically significant. The effect of failure feedback on pain avoidance was moderated by trait-NA. Only in the subgroup of patients who scored low on trait-NA did failure feedback decrease pain avoidance. State-NA did not mediate the effects of feedback. In line with previous findings, pain-related fear resulted in lower pain tolerance. Moreover, this study was the first to show that pain-related fear predicted higher pain report in CLBP patients. Pain-related fear did not predict pain avoidance when pre-lifting pain and gender were controlled for. Finally, pre-lifting pain turned out to be the strongest predictor with regard to all pain measures. The role of pain-related fear and unexpected findings with regard to feedback are discussed as well as some clinical implications.
Persistent Pain after Breast Cancer Treatment: A Questionnaire-Based Study on the Prevalence, Associated Treatment Variables, and Pain Type
Christiansen, Peer; Damsgaard, Tine Engberg
Purpose Persistent pain is a common side effect of breast cancer treatment. The present study aimed to assess the prevalence, associated treatment-related factors, and the type of pain (neuropathic or nociceptive) in patients who had undergone a unilateral mastectomy. Methods All women who underwent a unilateral mastectomy at a University Hospital between 2009 and 2013 were eligible for inclusion. Women with breast reconstruction or active cancer were excluded. Participants were mailed a questionnaire evaluating the prevalence, location, intensity, and frequency of surgical site pain. Additionally, the painDETECT®, a validated instrument to evaluate neuropathic pain, was mailed to all participants. Results A total of 305 women were included, and of them, 261 (85.6%) completed the study questionnaire. After a median follow-up period of 3.0 years, 100 women (38.3%) reported experiencing pain at the surgical site. Body mass index ≥30 kg/m2, radiation therapy, and axillary lymph node dissection were significantly associated with persistent pain in univariate models. However, only body mass index ≥30 kg/m2 was independently associated with persistent pain (odds ratio, 2.13; 95% confidence interval, 1.06–4.27; p=0.034) in a multivariate analysis. Of the patients reporting pain, 71.0% were unlikely to have a neuropathic pain component. A moderate, but highly significant, positive correlation was observed between the pain intensity and the painDETECT® score (rs=0.47, p<0.001). Conclusion Persistent pain after breast cancer treatment continues to have a high prevalence. Our results indicate that the largest proportion of patients experiencing persistent pain after breast cancer treatment do not have a clear neuropathic pain component. PMID:28053634
Reduction of conditioned pain modulation in humans by naltrexone: an exploratory study of the effects of pain catastrophizing.
King, Christopher D; Goodin, Burel; Kindler, Lindsay L; Caudle, Robert M; Edwards, Robert R; Gravenstein, Nikolaus; Riley, Joseph L; Fillingim, Roger B
The current study tested the hypothesis that conditioned pain modulation is mediated by the release of endogenous opioids with a placebo-controlled (sugar pill) study of naltrexone (50 mg) in 33 healthy volunteers over two counter-balanced sessions. Pain modulation consisted of rating of heat pain (palm) during concurrent cold water immersion (foot). Compared to baseline heat pain ratings, concurrent foot immersion lowered pain intensity ratings, which suggests an inhibitory effect, was reduced with naltrexone, suggesting at least partial dependence of inhibition on endogenous opioids. An exploratory analysis revealed that individual differences in catastrophizing moderated the effects of naltrexone; endogenous opioid blockade abolished modulation in subjects lower in catastrophizing while modulation was unaffected by naltrexone among high catastrophizers. The results suggest a role of endogenous opioids in endogenous analgesia, but hint that multiple systems might contribute to conditioned pain modulation, and that these systems might be differentially activated as a function of individual differences in responses to pain.
The prevalence of uncontrolled pain in long-term care: a pilot study examining outcomes of pain management processes.
Good, Heidi; Riley-Doucet, Cheryl K; Dunn, Karen S
Pain in long-term care (LTC) is common among older residents despite the vast options available for optimal pain management. Inadequate pain management affects individual health care outcomes. Researcher evidence has shown that nurse practitioners (NPs) improve the quality of care in LTC but are challenged by multiple barriers that inhibit optimal pain control. The purpose of the current pilot study was to explore both the pain management processes used by nurses in LTC and the documented patient outcomes that come from these processes. In addition, factors were identified that may impact the NP role in providing adequate pain control in LTC. This descriptive study used a retrospective, case-controlled research design that incorporated reviewing 55 LTC resident medical records. Results show how the process of pain management in LTC can be improved by expanding the professional role of the NP.
Expectancy of pain is influenced by motor preparation: a high-resolution EEG study of cortical alpha rhythms.
Babiloni, Claudio; Brancucci, Alfredo; Capotosto, Paolo; Arendt-Nielsen, Lars; Chen, Andrew C N; Rossini, Paolo Maria
This high-resolution electroencephalographic (EEG) study on alpha event-related desynchronization (ERD) evaluated whether anticipatory activity precedes a sensorimotor interaction induced by concomitant painful stimuli and sensorimotor demand. An omitted-stimulus paradigm induced the expectancy of the painful stimulation at the left hand. In the experimental condition, the painful stimulation was associated with a visual go/no-go task triggering right-hand movements. Two control conditions manipulated the painful sensorimotor interaction variable. Compared with the control conditions, the expectancy of the painful sensorimotor interaction increased the high-band alpha EEG oscillations over the right primary sensorimotor cortex contralateral to the nociceptive stimuli and, to a lesser extent, over the centroparietal midline. These findings suggest that concomitant painful stimuli and simple sensorimotor go/no-go demands affect anticipatory activity as revealed by alpha ERD.
Evaluation of aromatherapy in treating postoperative pain: pilot study.
Kim, Jung T; Wajda, Michael; Cuff, Germaine; Serota, David; Schlame, Michael; Axelrod, Deborah M; Guth, Amber A; Bekker, Alex Y
This study compared the analgesic efficacy of postoperative lavender oil aromatherapy in 50 patients undergoing breast biopsy surgery. Twenty-five patients received supplemental oxygen through a face mask with two drops of 2% lavender oil postoperatively. The remainder of the patients received supplemental oxygen through a face mask with no lavender oil. Outcome variables included pain scores (a numeric rating scale from 0 to 10) at 5, 30, and 60 minutes postoperatively, narcotic requirements in the postanesthesia care unit (PACU), patient satisfaction with pain control, as well as time to discharge from the PACU. There were no significant differences in narcotic requirements and recovery room discharge times between the two groups. Postoperative lavender oil aromatherapy did not significantly affect pain scores. However, patients in the lavender group reported a higher satisfaction rate with pain control than patients in the control group (P = 0.0001).
Randomized controlled pilot study: pain intensity and pressure pain thresholds in patients with neck and low back pain before and after traditional East Asian "gua sha" therapy.
Lauche, Romy; Wübbeling, Klaus; Lüdtke, Rainer; Cramer, Holger; Choi, Kyung-Eun; Rampp, Thomas; Michalsen, Andreas; Langhorst, Jost; Dobos, Gustav J
Gua Sha is a traditional East Asian healing technique where the body surface is "press-stroked" with a smooth-edged instrument to raise therapeutic petechiae that last 2-5 days. The technique is traditionally used in the treatment of both acute and chronic neck and back pain. This study aimed to measure the effects of Gua Sha therapy on the pain ratings and pressure pain thresholds of patients with chronic neck pain (CNP) and chronic low back pain (CLBP). A total of 40 patients with either CNP or CLBP (mean age 49.23 ± 10.96 years) were randomized to either a treatment group (TG) or a waiting list control group (WLC). At baseline assessment (T1), all patients rated their pain on a 10 cm visual analog scale (VAS). Patients' pressure pain thresholds (PPT) at a site of maximal pain (pain-maximum) and an adjacent (pain-adjacent) site were also established. The treatment group then received a single Gua Sha treatment. Post-intervention measurements were taken for both groups at T2, seven days after baseline assessment (T1), using the same VAS and PPT measurements in precisely the same locations as at T1. Final analysis were conducted with 21 patients with CNP and 18 patients with CLBP. The study groups were equally distributed with regard to randomization. Patients in both the CNP and the CLBP treatment groups reported pain reduction (p < 0.05) and improved health status from their one Gua Sha treatment, as compared to the waiting list group. Pain sensitivity improved in the TG in CNP, but not in CLBP patients, possibly due to higher pressure sensitivity in the neck area. No adverse events were reported. These results suggest that Gua Sha may be an effective treatment for patients with chronic neck and low back pain. Further study of Gua Sha is warranted.
The re-evaluation of the measurement of pain in population-based epidemiological studies: The SHAMA study
Flüß, Elisa; Bond, Christine M; Jones, Gareth T
Background: While many pain patients rely on pain-relieving treatments to manage their pain, pain-related research commonly quantifies pain status using validated questionnaires without taking into account that information. This will lead to an underestimate of the burden of pain in the community. To ensure a more accurate assessment of the prevalence and severity of pain, this study aimed to develop a pain management questionnaire and to assess how much population-based pain estimates change when pain management is considered. Methods: This study was a cross-sectional population-based study in Grampian, north-east Scotland. A total of 4600 people, aged 25 years and over, were randomly selected from a population sample frame and sent a questionnaire on pain and pain management. Population estimates of pain were determined twice: with the use of standard pain status questionnaires ('current pain') and with the use of a newly developed enhanced pain status questionnaire to determine patients' estimated pain without pain management ('all pain'). Results: The prevalence of current pain was 50.5% (95% CI = 48.0, 52.9). Of those who reported no current pain, 11.6% (95% CI = 9.4, 13.8) reported that they would have had pain had they not managed their pain. Thus, the all pain prevalence was 56.2% (95% CI = 53.7, 58.7). This difference in prevalence rates was statistically significant (difference = 5.7%; 95% CI = 2.2, 9.2). Likewise, participants' pain severity significantly increased when they estimated their pain without pain management (p < 0.001, Wilcoxon-signed rank test). Conclusions: Failure to assess pain management information results in an underestimation of pain prevalence and severity. This should be considered in future epidemiological studies. Summary points Pain management information is currently not considered for the assessment of pain in epidemiological population-based studies. Since pain management can affect
Orienting Attention Modulates Pain Perception: An ERP Study
Chan, Sam C. C.; Chan, Chetwyn C. H.; Kwan, Anne S. K.; Ting, Kin-hung; Chui, Tak-yi
Introduction Research has shown that people with chronic pain have difficulty directing their attention away from pain. A mental strategy that incorporates focused attention and distraction has been found to modulate the perception of pain intensity. That strategy involves placing attention on the nociceptive stimulus felt and shifting attention to a self-generated sub-nociceptive image and rehearsing it. Event-related potential was used to study the possible processes associated with the focus-then-orient strategy. Methods Eighteen pain-free participants received different levels of 50-ms nociceptive stimulations elicited by electric shocks at the right lateral malleolus (ankle). In perception trials, participants maintained the perceived nociceptive stimulus in working memory for 3,000 ms. In imagery trials, participants mentally generated and maintained the corresponding sub-nociceptive image they had learned previously. After both types of trials, participants evaluated the pain intensity of the incoming stimulus by recalling the feeling of the nociceptive stimulation at the beginning of the trial. Results Shifting attention from the incoming nociceptive to a self-generated sub-nociceptive image elicited central P2 and centro-parietal P3 waves, which were found to correlate with proportional scores on the Stroop Test. They were followed by a frontal N400 and a parietal P600, denoting generation of sub-nociceptive images in working memory. The voltages elicited in these potentials correlated moderately with attenuation of the pain ratings of the recalled nociceptive stimulations. Conclusions Focus-and-orient attention across nociceptive and sub-nociceptive images appears to be related to response inhibition. Mental rehearsal of the sub-nociceptive images was found to modulate the perception of the nociceptive sensation felt prior to the imagery. Such modulation seems to be mediated by generating and maintaining sub-nociceptive images in working memory. Future
A behavioral medicine intervention for older women living alone with chronic pain – a feasibility study
Cederbom, Sara; Rydwik, Elisabeth; Söderlund, Anne; Denison, Eva; Frändin, Kerstin; von Heideken Wågert, Petra
Background To be an older woman, live alone, have chronic pain, and be dependent on support are all factors that may have an impact on daily life. One way to promote ability in everyday activities in people with pain-related conditions is to use individualized, integrated behavioral medicine in physical therapy interventions. How this kind of intervention works for older women living alone at home, with chronic pain, and dependent on formal care to manage their everyday lives has not been studied. The aim was to explore the feasibility of a study and to evaluate an individually tailored integrated behavioral medicine in physical therapy intervention for the target group of women. Materials and methods The study was a 12-week randomized trial with two-group design. Primary effect outcomes were pain-related disability and morale. Secondary effect outcomes focused on pain-related beliefs, self-efficacy for exercise, concerns of falling, physical activity, and physical performance. Results In total, 23 women agreed to participate in the study and 16 women completed the intervention. The results showed that the behavioral medicine in physical therapy intervention was feasible. No effects were seen on the primary effect outcomes. The experimental intervention seemed to improve the level of physical activity and self-efficacy for exercise. Some of the participants in both groups perceived that they could manage their everyday life in a better way after participation in the study. Conclusion Results from this study are encouraging, but the study procedure and interventions have to be refined and tested in a larger feasibility study to be able to evaluate the effects of these kinds of interventions on pain-related disability, pain-related beliefs, self-efficacy in everyday activities, and morale in the target group. Further research is also needed to refine and evaluate effects from individualized reminder routines, support to collect self-report data, safety procedures for
Interdisciplinary hospice team processes and multidimensional pain: a qualitative study.
Dugan Day, Michele
Hospice teams may address multidimensional pain through the synergistic interaction of team members from various professional disciplines during regularly scheduled team meetings. However, the occurrence of that critical exchange has not been adequately described or documented. The purpose of this qualitative study was to explore two processes in team pain palliation: communication and collaboration. Data were gathered through individual interviews and a 1-year observation of team members from two hospices (physicians, nurses, aides, chaplains, social workers). Utilizing constant comparison, 14 final thematic categories were discovered. Use of biopsychosocial/spiritual terms by all team members meant that the team had the common language needed to communicate about multidimensional pain. Interviews and observation revealed a gap in translating multidisciplinary communication in team meetings into collaborative acts for pain treatment. In addition, structural influences inhibited creativity in pain palliation. There was no mutual understanding of the purpose for team meetings, no recognition of the need to reflect on team process, or common definition of leadership. Social work roles in hospice should include leadership that moves teams toward interdisciplinary care for multidimensional pain.
A pilot study of pain-related anxiety and smoking-dependence motives among persons with chronic pain.
Ditre, Joseph W; Zale, Emily L; Kosiba, Jesse D; Zvolensky, Michael J
Complex interactions between pain and tobacco smoking have been of increasing interest to researchers and clinicians from a variety of disciplines. There is also recent evidence to suggest that pain-related anxiety may play an important role in the maintenance of tobacco dependence among persons with comorbid pain disorders. The goal of the current study was to evaluate the explanatory relevance of pain-related anxiety in relation to tobacco dependence among a sample of daily smokers with current chronic pain. Participants were recruited from the general population to complete an online survey that was developed to examine interrelations between chronic pain and tobacco smoking. Fifty-six of 129 (43%) daily smoking respondents met criteria for current chronic pain. Results indicated that pain-related anxiety accounted for a significant portion of the unique variance in total smoking dependence scores, and both primary and secondary dependence composite scores (as measured by the Wisconsin Inventory of Smoking Dependence Motives; Piper et al., 2004). It is noteworthy that these effects were observed above and beyond the variance accounted for by relevant sociodemographic factors, generalized anxiety, and pain severity. Pain-related anxiety was observed to be strongly associated with secondary dependence motives, which is consistent with a conceptualization of pain-related anxiety as an instrumental or situational motivator of smoking. These results suggest that tobacco smokers with comorbid pain disorders may be at risk for maintaining or exacerbating their dependence on tobacco, possibly due to individual differences in pain-related anxiety. These findings may help inform the development of tailored interventions for smokers with comorbid chronic pain.
Changes in pain intensity and health related quality of life with Iyengar yoga in nonspecific chronic low back pain: A randomized controlled study
Nambi, Gopal S; Inbasekaran, Dipika; Khuman, Ratan; Devi, Surbala; Shanmugananth; Jagannathan, K
Background: Nonspecific chronic low back (nCLBP) pain is prevalent among adult population and often leads to functional limitations, psychological symptoms, lower quality of life (QOL), and higher healthcare costs. The purpose of this study was to determine the efficacy of Iyengar yoga therapy on pain intensity and health related quality of life (HRQOL) with nCLBP. Aim of the Study: To compare the effect of Iyengar yoga therapy and conventional exercise therapy on pain intensity and HRQOL in nonspecific chronic low back pain. Materials and Methods: Experimental study with random sampling technique. Subjects/Intervention: Sixty subjects who fulfilled the selection criteria were randomly assigned to Iyengar yoga (yoga group, n = 30) and control group (exercise group, n = 30). Participants completed low back pain evaluation form and HRQOL-4 questionnaire before their intervention and again 4 weeks and 6 month later. Yoga group underwent 29 yogic postures training and exercise group had undergone general exercise program for 4 weeks. Statistics: Repeated measures analysis of variance (ANOVA) was used to analyze group differences over time, while controlling for baseline differences. Results: Patients in both groups experienced significant reduction in pain and improvement in HRQOL. In visual analogue scale (VAS) yoga group showed reduction of 72.81% (P = 0.001) as compared to exercise group 42.50% (P = 0.001). In HRQOL, yoga group showed reduction of 86.99% (P = 0.001) as compared to exercise group 67.66% (P = 0.001). Conclusion: These results suggest that Iyengar yoga provides better improvement in pain reduction and improvement in HRQOL in nonspecific chronic back pain than general exercise. PMID:25035607
Daily living pain assessment in children with autism: Exploratory study.
Dubois, A; Michelon, C; Rattaz, C; Zabalia, M; Baghdadli, A
This study aims to broaden knowledge about pain expression and assessment in daily life situations in children with Autism Spectrum Disorder (ASD). The goals are to provide a description of the responses of the GED-DI, the French version of the NCCPC, and to test the internal structure validity of this scale. Thirty five children with ASD were included in this study (mean age=58months; mean developmental age=32months). The French version of the NCCPC was filled in by parents. Descriptive analysis of responses shows that children with ASD express pain through varied and common behaviours, related to different expressive markers (vocal, facial, activity, etc.). Behaviours more specific to the symptomology and disturbances of ASD are also displayed. A four-factor solution (negative emotional reaction, idiosyncratic expression, hyper-vigilance reaction, pain expression) emerges from an exploratory factor analysis that explains 54.4% of the total variance. Correlation coefficients show good psychometric qualities in terms of internal consistency, factorial validity and discriminant validity. This study provides new data about pain expression in daily life situations and shows that the French version of NCCPC adjusted to ASD children is relevant to assess pain in daily life situations.
Transcranial direct current stimulation (tDCS) priming of 1Hz repetitive transcranial magnetic stimulation (rTMS) modulates experimental pain thresholds.
Moloney, Tonya M; Witney, Alice G
Transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) of primary motor cortex (M1) modulate cortical excitability. Both techniques have been demonstrated to modulate chronic pain and experimental pain thresholds, but with inconsistent effects. Preconditioning M1 with weak tDCS (1mA) standardizes the effects of subsequent stimulation via rTMS on levels of cortical excitability. Here we examine whether 1Hz rTMS, primed with tDCS, could effectively standardize the modulation of pain thresholds. Thermal pain thresholds were determined using quantitative sensory testing (QST) of the palmar thenar of both hands in 12 healthy males pre and post tDCS - 1Hz rTMS over the hand area of the left M1. Cathodal tDCS preconditioning of 1Hz rTMS successfully reversed the normal suppressive effect of low frequency rTMS and effectively modulated cold and heat pain thresholds. Conversely, anodal tDCS - 1Hz rTMS led to a decrease in cold pain thresholds. Therefore, this study supports that preconditioning M1 using cathodal tDCS before subsequent stimulation via 1Hz rTMS facilitates the production of analgesia.
A population-based study of quantitative sensory testing in adolescents with and without chronic pain.
Tham, See Wan; Palermo, Tonya M; Holley, Amy Lewandowski; Zhou, Chuan; Stubhaug, Audun; Furberg, Anne-Sofie; Nielsen, Christopher Sivert
Quantitative sensory testing (QST) has been used to characterize pain sensitivity in individuals with and without pain conditions. Research remains limited in pediatric populations, hindering the ability to expand the utility of QST toward its potential application in clinical settings and clinical predictive value. The aims of this study were to examine pain sensitivity using QST in adolescents with chronic pain compared to adolescents without chronic pain and identify predictors of pain sensitivity. A population-based study conducted from 2010 to 2011 provided data on 941 adolescents, 197 were classified as having chronic pain and 744 were classified without chronic pain. Self-reported data on pain characteristics, psychological functioning, and QST responses were examined. The findings revealed lower pressure pain threshold and tolerance on the trapezius (P's = 0.03) in adolescents with chronic pain compared to adolescents without chronic pain, but no differences on heat or cold-pressor pain tasks. Female sex (P's = 0.02) and poorer psychological functioning (P's = 0.02) emerged as significant predictors of greater pain sensitivity across all pain modalities. Exploratory analyses revealed several associations between clinical pain characteristics and QST responses within the chronic pain cohort. Findings from this large pediatric sample provide comprehensive data that could serve as normative data on QST responses in adolescents with and without chronic pain. These findings lay the groundwork toward developing future QST research and study protocols in pediatric populations, taking into consideration sex and psychological distress.
A Pilot Study of a Mobile Health Pain Coping Skills Training Protocol for Patients with Persistent Cancer Pain
Somers, Tamara J.; Abernethy, Amy P.; Edmond, Sara N.; Kelleher, Sarah A.; Wren, Anava A.; Samsa, Greg P.; Keefe, Francis J.
Context Pain coping skills training (PCST) interventions have shown efficacy for reducing pain and providing other benefits in patients with cancer. However, their reach is often limited because of a variety of barriers (e.g., travel, physical burden, cost, time). Objectives This study examined the feasibility and acceptability of a brief PCST intervention delivered to patients in their homes using mobile health (mHealth) technology. Pre-to-post intervention changes in pain, physical functioning, physical symptoms, psychological distress, self-efficacy for pain management, and pain catastrophizing also were examined. Methods Patients with a diagnosis of breast, lung, prostate, or colorectal cancer who reported persistent pain (N=25) participated in a four-session intervention delivered using mHealth technology (video-conferencing on a tablet computer). Participants completed measures of pain, physical functioning, physical symptoms, psychological distress, self-efficacy for pain management, and pain catastrophizing. We also assessed patient satisfaction. Results Participants completed an average of 3.36 (SD=1.11) of the four intervention sessions for an overall session completion rate of 84%. Participants reported that the program was of excellent quality and met their needs. Significant pre- to post-intervention differences were found in pain, physical symptoms, psychological distress, and pain catastrophizing. Conclusion The use of mHealth technology is a feasible and acceptable option for delivery of PCST for patients with cancer. This delivery mode is likely to dramatically increase intervention access for cancer patients with pain compared to traditional in-person delivery. Preliminary data also suggest that the program is likely to produce pre- to post-treatment decreases in pain and other important outcomes. PMID:26025279
Central poststroke pain: a population-based study.
Klit, Henriette; Finnerup, Nanna Brix; Andersen, Grethe; Jensen, Troels Staehelin
Central poststroke pain (CPSP) is a specific pain condition arising as a direct consequence of a cerebrovascular lesion. There is limited knowledge about the epidemiology and clinical characteristics of this often neglected but important consequence of stroke. In this population-based study, a questionnaire was sent out to all (n=964) stroke patients identified through the Danish National Indicator Project Stroke Database in Aarhus County, Denmark, between March 2004 and February 2005. All surviving patients who fulfilled 4 questionnaire criteria for possible CPSP (n=51) were selected for further clinical examination, and their pain was classified by using stringent and well-defined criteria and a detailed, standardized clinical examination. The minimum prevalence of definite or probable CPSP in this population is 7.3% and the prevalence of CPSP-like dysesthesia or pain is 8.6%. Pinprick hyperalgesia was present in 57%, cold allodynia in 40%, and brush-evoked dysesthesia in 51% of patients with CPSP. Because of its negative impact on quality of life and rehabilitation, pain is an important symptom to assess in stroke survivors.
Pain management protocols, peri-operative pain and patient satisfaction after total knee replacement: a multicentre study.
Chang, C B; Cho, W S
In a prospective multicentre study we investigated variations in pain management used by knee arthroplasty surgeons in order to compare the differences in pain levels among patients undergoing total knee replacements (TKR), and to compare the effectiveness of pain management protocols. The protocols, peri-operative levels of pain and patient satisfaction were investigated in 424 patients who underwent TKR in 14 hospitals. The protocols were highly variable and peri-operative pain levels varied substantially, particularly during the first two post-operative days. Differences in levels of pain were greatest during the night after TKR, when visual analogue scores ranged from 16.9 to 94.3 points. Of the methods of managing pain, the combined use of peri-articular infiltration and nerve blocks provided better pain relief than other methods during the first two post-operative days. Patients managed with peri-articular injection plus nerve block, and epidural analgesia were more likely to have higher satisfaction at two weeks after TKR. This study highlights the need to establish a consistent pain management strategy after TKR.
Distinctiveness of long-term pain that does not interfere with life: An observational cohort study
Jordan, KP; Sim, J; Moore, A; Bernard, M; Richardson, J
Background Reporting of pain that does not interfere with life is common in the older population but little is known about people with such long-term non-interfering pain. Objectives To assess whether non-interfering pain can be a long-term state, and to compare this group with those who continuously report no pain, and with those with chronic pain that interferes with life. Methods This was a prospective general population cohort study set within the North Staffordshire Osteoarthritis Project (NorStOP). People aged 50 plus were sent baseline, 3-year and 6-year questionnaires. Those who reported the same pain status (no pain, non-interfering pain, interfering pain) at each time point were compared on pain intensity, widespread pain and medication, and on sociodemographic and co-morbid characteristics at 6 years. Results Forty percent of responders reported the same pain status at each time point; 12% reported long-term non-interfering pain. Fifty-nine percent of those with non-interfering pain reported at least one site of high pain intensity, 33% reported widespread pain, and 90% had used pain medication in the past 4 weeks. This group was similar to the no-pain group but distinct on sociodemographic and co-morbid measures from those with pain that interfered. Conclusions Long-term non-interfering pain is common, but despite often suffering from high pain intensity and widespread pain, those within this group seem to be able to control their pain without allowing it to affect their everyday lives. Future work is needed to assess how people with long-term pain ensure it does not cause interference with life. PMID:22887341
Distinguishing affective and somatic dimensions of pain and depression: a confirmatory factor analytic study.
Lerman, Sheera F; Rudich, Zvia; Shahar, Golan
In this study, we examined the overlap between pain and depression in a sample of 342 chronic pain patients treated at a specialty pain clinic. Confirmatory factor analysis was conducted to test the differentiation of pain and depression measured as latent factors derived from the subscales of the Short Form McGill Pain Questionnaire and the Center for Epidemiological Studies Depression Scale. The affective pain subscale did not load on latent depression and the somatic depression subscale loaded weakly on latent pain. Although pain and depression are linked, we found that affective pain is distinct from depression, and that somatic depression is distinct from pain. This finding justifies further examination of the casual relationship between pain and depression.
Five-factor personality traits and pain sensitivity: a twin study.
Vassend, Olav; Røysamb, Espen; Nielsen, Christopher S
Factors underlying individual differences in pain responding are incompletely understood, but are likely to include genetic influences on basal pain sensitivity in addition to demographic characteristics such as age, sex, and ethnicity, and psychological factors including personality. This study sought to explore the relationship between personality traits and experimental pain sensitivity, and to determine to what extent the covariances between these phenotypes are mediated by common genetic and environmental factors. A sample composed of 188 twins, aged 23 to 35years, was included in the study. Heat pain intensity (HPI) and cold-pressor pain intensity (CPI) ratings were obtained using standardized pain testing procedures, and personality traits were assessed with the NEO Personality Inventory, Revised. Associations between personality and the pain sensitivity indices were examined using zero-order correlations and generalized estimating equations. Bivariate Cholesky models were used in the biometric analyses. The most robust finding was a significant phenotypic association between CPI and the personality facets Impulsiveness (a facet of Neuroticism) and Excitement-Seeking (a facet of Extraversion), and estimates of the genetic correlation were .37 (P<.05) and .43 (P<.05), respectively. In contrast, associations between HPI and personality seemed weak and unstable, but a significant effect of Angry Hostility (a facet of Neuroticism) emerged in generalized estimating equations analysis. Although the genetic correlation between these phenotypes was essentially zero, a weak but significant individual-specific environmental correlation emerged (re=.21, P<.05). Taken together, these findings suggest that CPI is more consistently related to personality dispositions than HPI, both phenotypically and genetically.
Experimental study of vortex diffusers
Shakerin, S.; Miller, P.L.
This report documents experimental research performed on vortex diffusers used in ventilation and air-conditioning systems. The main objectives of the research were (1) to study the flow characteristics of isothermal jets issuing from vortex diffusers, (2) to compare the vortex diffuser`s performance with that of a conventional diffuser, and (3) to prepare a report that disseminates the results to the designers of ventilation and air-conditioning systems. The researchers considered three diffusers: a conventional round ceiling diffuser and two different styles of vortex diffusers. Overall, the vortex diffusers create slightly more induction of ambient air in comparison to the conventional diffuser.
Experimental studies of glass refining
NASA Technical Reports Server (NTRS)
Subramanian, R. S.; Cole, R.; Kondos, P.
The basic components of the experimental apparatus were selected and acquired. Techniques were developed for the fabrication of the special crucibles necessary for the experiments. Arrangements were made for the analysis of glass and gas bubble samples for composition information. Donations of major equipment were received for this project from Owens, Illinois where a similar study had been conducted a few year ago. Decisions were made regarding the actual glass composition to be used, the gas to be used in the first experiments, and the temperatures at which the experiments should be conducted. A microcomputer was acquired, and work was begun on interfacing the video analyzer to it.
Effect of a virtual pain coach on older adults' pain communication: a pilot study.
McDonald, Deborah Dillon; Gifford, Timothy; Walsh, Stephen
A randomized posttest-only double blind design was used to pilot test the effect of a virtual practitioner pain communication coach on older adults' communication of their osteoarthritis pain. Baseline pain intensity and pain interference with activities were measured using the Brief Pain Inventory Short Form. Thirty older adults watched a video of a practitioner describing important osteoarthritis pain information followed by either a virtual practitioner coach, a video practitioner coach, or no coach. Participants were next asked, via a videotaped health care practitioner, to orally describe their pain as if speaking to their own practitioner. The amount of important distinctive pain information described by the older adults was audiotaped, transcribed, content analyzed, and summed using a priori criteria from the American Pain Society osteoarthritis pain management guidelines. Older adults described M=6.3 (SD=3.17), M=3.0 (SD=2.08), and M=5.2 (SD=2.40) items of important pain information as a result of the virtual coach, video coach, and no coach conditions, respectively; F(2,25)=3.17, p=.06, η²=.01. Older adults who practiced talking with the virtual coach described more than one additional item of important pain information. The clinically significant group difference supports the need to test the intervention in a randomized clinical trial. The virtual coaching and education intervention might enable older adults to communicate their pain management information more effectively to their practitioners.
Identification of clusters of individuals relevant to temporomandibular disorders and other chronic pain conditions: the OPPERA study.
Bair, Eric; Gaynor, Sheila; Slade, Gary D; Ohrbach, Richard; Fillingim, Roger B; Greenspan, Joel D; Dubner, Ronald; Smith, Shad B; Diatchenko, Luda; Maixner, William
The classification of most chronic pain disorders gives emphasis to anatomical location of the pain to distinguish one disorder from the other (eg, back pain vs temporomandibular disorder [TMD]) or to define subtypes (eg, TMD myalgia vs arthralgia). However, anatomical criteria overlook etiology, potentially hampering treatment decisions. This study identified clusters of individuals using a comprehensive array of biopsychosocial measures. Data were collected from a case-control study of 1031 chronic TMD cases and 3247 TMD-free controls. Three subgroups were identified using supervised cluster analysis (referred to as the adaptive, pain-sensitive, and global symptoms clusters). Compared with the adaptive cluster, participants in the pain-sensitive cluster showed heightened sensitivity to experimental pain, and participants in the global symptoms cluster showed both greater pain sensitivity and greater psychological distress. Cluster membership was strongly associated with chronic TMD: 91.5% of TMD cases belonged to the pain-sensitive and global symptoms clusters, whereas 41.2% of controls belonged to the adaptive cluster. Temporomandibular disorder cases in the pain-sensitive and global symptoms clusters also showed greater pain intensity, jaw functional limitation, and more comorbid pain conditions. Similar results were obtained when the same methodology was applied to a smaller case-control study consisting of 199 chronic TMD cases and 201 TMD-free controls. During a median 3-year follow-up period of TMD-free individuals, participants in the global symptoms cluster had greater risk of developing first-onset TMD (hazard ratio = 2.8) compared with participants in the other 2 clusters. Cross-cohort predictive modeling was used to demonstrate the reliability of the clusters.
Dynamic pain phenotypes are associated with spinal cord stimulation-induced reduction in pain: A repeated measures observational pilot study
Campbell, Claudia M.; Buenaver, Luis F.; Raja, Srinivasa N.; Kiley, Kasey B.; Swedberg, Lauren; Wacnik, Paul W.; Cohen, Steven P.; Erdek, Michael A.; Williams, Kayode A.; Christo, Paul J.
Objective Spinal Cord Stimulation (SCS) has become a widely used treatment option for a variety of pain conditions. Substantial variability exists in the degree of benefit obtained from SCS and patient selection is a topic of expanding interest and importance. However, few studies have examined the potential benefits of dynamic Quantitative Sensory Testing (QST) to develop objective measures of SCS outcomes or as a predictive tool to help patient selection. Psychological characteristics have been shown to play an important role in shaping individual differences in the pain experience and may aid in predicting responses to SCS. Static laboratory pain-induction measures have also been examined in their capacity for predicting SCS outcomes. Methods The current study evaluated clinical, psychological and laboratory pain measures at baseline, during trial SCS lead placement, as well as one month and three months following permanent SCS implantation in chronic pain patients who received SCS treatment. Several QST measures were conducted, with specific focus on examination of dynamic models (central sensitization and conditioned pain modulation [CPM]) and their association with pain outcomes three months post SCS implantation. Results Results suggest few changes in QST over time. However, central sensitization and CPM at baseline were significantly associated with clinical pain at three months following SCS implantation, controlling for psycho/behavioral factors and pain at baseline. Specifically, enhanced central sensitization and reduced CPM were associated with less self-reported pain three months following SCS implantation. Conclusions These findings suggest a potentially important role for dynamic pain assessment in individuals undergoing SCS, and hint at potential mechanisms through which SCS may impart its benefit. PMID:25800088
Pain Experience in Hemophilia Patients: A Hermeneutic Phenomenological Study
Rambod, Masoume; Sharif, Farkhondeh; Molazem, Zahra; Khair, Kate
ABSTRACT Background: Pain, as a crucial subsequence of joint hemorrhages in hemophilia patients, is chronic, debilitating, and distracting. This study aimed to describe and interpret pain experiences of hemophilia patients in their lives. Methods: This qualitative study with hermeneutic phenomenological approach was conducted on fourteen hemophilia patients who had been referred to a hemophilia center affiliated to Shiraz University of Medical Sciences, Shiraz, Iran. The study question was "what is the meaning of pain in hemophilia patients' lives? The data were collected through semi-structured interviews and field notes through purposeful sampling. Then, thematic analysis with van Manen's six-step methodological framework was used. MAX.QDA qualitative software package, 2010, was used to analyze the data. Results: The three main themes that emerged in this study were "alteration in physical health", "engagement in psychological problems", and "impairment in social relationships". Alteration in physical health consisted of three subthemes, namely "impairment of physical function", "change in body physics", and "disturbance in sleep quality". In addition, two subthemes including "nostalgia of pain in adults with hemophilia" and "psychological distress" emerged from engagement in psychological problems. Finally, "loss of social activity" and "change in relationships" were related to impairment in social relationships. Conclusion: The present study highlighted alteration in physical health, engagement in psychological problems, and impairment in social relationship as a result of pain in hemophilia patients. Thus, healthcare providers and family members have to pay special attention to these problems. Besides, providing complementary therapy interventions is suggested for reducing these issues. PMID:27713894
Association between sensitisation and pain-related behaviours in an experimental canine model of osteoarthritis.
Rialland, Pascale; Otis, Colombe; Moreau, Maxim; Pelletier, Jean-Pierre; Martel-Pelletier, Johanne; Beaudry, Francis; Del Castillo, Jerome R E; Bertaim, Thierry; Gauvin, Dominique; Troncy, Eric
Evaluation of nociceptive sensitisation in canine osteoarthritis studies has been poorly reported, or even related to other clinical symptoms. In 16 dogs, peak vertical force (PVF), subjective pain assessment using 3 scales, sympathetic stress response with electrodermal activity (EDA) measurement, and behavioural changes with video analysis and telemetered motor activity were quantified at baseline (D-7), and 28 and 56 days post transection of the cranial cruciate ligament. As markers of central sensitisation, selected spinal cord biomarkers (substance P and transthyretin) were quantified at D56. Electrical withdrawal thresholds on the stifle and the tail were measured as indicative of peripheral and central quantitative sensory testing (QST) sensitisation, respectively. The effects of vehicle administration (n=8) were compared with tiludronate (2mg/kg subcutaneously, q2 week, starting at D0) administration. Generalized estimated equations tested the association between the behavioural and physiological methods and QST sensitisation, and therefore the sensitivity of the methods for detecting treatment efficacy. Compared to tiludronate, at D56, vehicle-treated dogs had increased spinal substance P (P=0.01), concomitant decreased transthyretin (P=0.02), and (compared to baseline) demonstrated peripheral and central QST sensitisation, which was not present for tiludronate. Only PVF, the spontaneous behaviour "walking with full weight-bearing," and EDA were associated with occurrence of QST sensitisation and indicated significant tiludronate analgesic efficacy after inclusion of central QST sensitisation as a predictor variable in the statistical model. This study establishes the strong interest to implement QST as a predictor of canine osteoarthritis pain symptoms explained by pain sensitisation.
Chenopodium ambrosioides L. Reduces Synovial Inflammation and Pain in Experimental Osteoarthritis
Calado, Gustavo P.; Lopes, Alberto Jorge O.; Costa Junior, Livio M.; Lima, Francisco das Chagas A.; Silva, Lucilene A.; Pereira, Wanderson S.; do Amaral, Flávia M. M.; Garcia, João Batista S.; Cartágenes, Maria do Socorro de S.; Nascimento, Flávia R. F.
The chronicity of osteoarthritis (OA), characterized by pain and inflammation in the joints, is linked to a glutamate receptor, N-methyl-D-aspartate (NMDA). The use of plant species such as Chenopodium ambrosioides L. (Amaranthaceae) as NMDA antagonists offers a promising perspective. This work aims to analyze the antinociceptive and anti-inflammatory responses of the crude hydroalcoholic extract (HCE) of C. ambrosioides leaves in an experimental OA model. Wistar rats were separated into six groups (n = 24): clean (C), negative control (CTL-), positive control (CTL+), HCE0.5, HCE5 and HCE50. The first group received no intervention. The other groups received an intra-articular injection of sodium monoiodoacetate (MIA) (8 mg/kg) on day 0. After six hours, they were orally treated with saline, Maxicam plus (meloxicam + chondroitin sulfate) and HCE at doses of 0.5 mg/kg, 5 mg/kg and 50 mg/kg, respectively. After three, seven and ten days, clinical evaluations were performed (knee diameter, mechanical allodynia, mechanical hyperalgesia and motor activity). On the tenth day, after euthanasia, synovial fluid and draining lymph node were collected for cellular quantification, and cartilage was collected for histopathological analysis. Finally, molecular docking was performed to evaluate the compatibility of ascaridole, a monoterpene found in HCE, with the NMDA receptor. After the third day, HCE reduced knee edema. HCE5 showed less cellular infiltrate in the cartilage and synovium and lower intensities of allodynia from the third day and of hyperalgesia from the seventh day up to the last treatment day. The HCE5 and HCE50 groups improved in forced walking. In relation to molecular docking, ascaridole showed NMDA receptor binding affinity. C. ambrosioides HCE was effective in the treatment of OA because it reduced synovial inflammation and behavioral changes due to pain. This effect may be related to the antagonistic effect of ascaridole on the NMDA receptor. PMID:26524084
Chenopodium ambrosioides L. Reduces Synovial Inflammation and Pain in Experimental Osteoarthritis.
Calado, Gustavo P; Lopes, Alberto Jorge O; Costa Junior, Livio M; Lima, Francisco das Chagas A; Silva, Lucilene A; Pereira, Wanderson S; Amaral, Flávia M M do; Garcia, João Batista S; Cartágenes, Maria do Socorro de S; Nascimento, Flávia R F
The chronicity of osteoarthritis (OA), characterized by pain and inflammation in the joints, is linked to a glutamate receptor, N-methyl-D-aspartate (NMDA). The use of plant species such as Chenopodium ambrosioides L. (Amaranthaceae) as NMDA antagonists offers a promising perspective. This work aims to analyze the antinociceptive and anti-inflammatory responses of the crude hydroalcoholic extract (HCE) of C. ambrosioides leaves in an experimental OA model. Wistar rats were separated into six groups (n = 24): clean (C), negative control (CTL-), positive control (CTL+), HCE0.5, HCE5 and HCE50. The first group received no intervention. The other groups received an intra-articular injection of sodium monoiodoacetate (MIA) (8 mg/kg) on day 0. After six hours, they were orally treated with saline, Maxicam plus (meloxicam + chondroitin sulfate) and HCE at doses of 0.5 mg/kg, 5 mg/kg and 50 mg/kg, respectively. After three, seven and ten days, clinical evaluations were performed (knee diameter, mechanical allodynia, mechanical hyperalgesia and motor activity). On the tenth day, after euthanasia, synovial fluid and draining lymph node were collected for cellular quantification, and cartilage was collected for histopathological analysis. Finally, molecular docking was performed to evaluate the compatibility of ascaridole, a monoterpene found in HCE, with the NMDA receptor. After the third day, HCE reduced knee edema. HCE5 showed less cellular infiltrate in the cartilage and synovium and lower intensities of allodynia from the third day and of hyperalgesia from the seventh day up to the last treatment day. The HCE5 and HCE50 groups improved in forced walking. In relation to molecular docking, ascaridole showed NMDA receptor binding affinity. C. ambrosioides HCE was effective in the treatment of OA because it reduced synovial inflammation and behavioral changes due to pain. This effect may be related to the antagonistic effect of ascaridole on the NMDA receptor.
Effectiveness of Self-Hypnosis on the Relief of Experimental Dental Pain: A Randomized Trial.
Wolf, Thomas Gerhard; Wolf, Dominik; Below, Dagna; d'Hoedt, Bernd; Willershausen, Brita; Daubländer, Monika
This randomized, controlled clinical trial evaluates the effectiveness of self-hypnosis on pain perception. Pain thresholds were measured, and a targeted, standardized pain stimulus was created by electrical stimulation of the dental pulp of an upper anterior tooth. Pain stimulus was rated by a visual analogue scale (VAS). The pain threshold under self-hypnosis was higher (57.1 ± 17.1) than without hypnotic intervention (39.5 ± 11.8) (p < .001). Pain was rated lower on the VAS with self-hypnosis (4.0 ± 3.8) than in the basal condition without self-hypnosis (7.1 ± 2.7) (p < .001). Self-hypnosis can be used in clinical practice as an adjunct to the gold standard of local anesthesia for pain management, as well as an alternative in individual cases.
Patella malalignment, pain and patellofemoral progression: The Health ABC Study
Hunter, DJ; Zhang, YQ; Niu, JB; Felson, DT; Kwoh, K; Newman, A; Kritchevsky, S; Harris, T; Carbone, L; Nevitt, M
Objective Patellofemoral (PF) joint OA is strongly correlated with lower extremity disability and knee pain. Risk factors for pain and structural progression in patellofemoral OA are poorly understood. Our objective was to determine the association between patella malalignment and its relation to pain severity, and PF OA disease progression. Methods We conducted an analysis of data from the Health ABC knee OA study. Health ABC is a community based, multi-center cohort study of 3,075 Caucasian and Black men and women aged 70–79 at enrollment. Weight bearing skyline knee x-rays were obtained in a subset (595) of subjects, with and without knee pain, at year 2 and year 5 (mean follow-up 36 months). Films were read paired, and patellofemoral osteophytes (OST) and narrowing (JSN) were scored on a 0–3 scale using the OARSI atlas. We defined progression of PF OA as any increase in JSN score. 3 measures of patella malalignment were made: sulcus angle; patella tilt angle; and patella subluxation medially or laterally (bisect offset). Knee symptoms were assessed using a knee specific WOMAC knee pain subscale. We assessed the relationship between baseline patella malalignment and pain severity (linear regression for WOMAC) and compartment specific PF OA progression (logistic regression for dichotomous outcomes). We classified continuous measures of patella alignment into quartile groups. We performed multivariable adjusted logistic regression models, including age, gender and BMI to assess the relation of baseline patella alignment to the occurrence of PF JSN progression using generalized estimating equations. Results The subjects had a mean age 73.6 (SD 2.9), BMI 28.8 (SD 4.9), 40.3% male, and 46% were Black. Medial displacement of the patella predisposed to medial JSN progression; odds for each quartile 1, 1.2, 1.2, 2.2 (p for trend=0.03), whilst protecting from lateral JSN progression; odds for each quartile 1, 0.7, 0.6, 0.4 (p for trend=0.0004). Increasing patella
Does weather affect daily pain intensity levels in patients with acute low back pain? A prospective cohort study.
Duong, Vicky; Maher, Chris G; Steffens, Daniel; Li, Qiang; Hancock, Mark J
The aim of this study was to investigate the influence of various weather parameters on pain intensity levels in patients with acute low back pain (LBP). We performed a secondary analysis using data from the PACE trial that evaluated paracetamol (acetaminophen) in the treatment of acute LBP. Data on 1604 patients with LBP were included in the analysis. Weather parameters (precipitation, temperature, relative humidity, and air pressure) were obtained from the Australian Bureau of Meteorology. Pain intensity was assessed daily on a 0-10 numerical pain rating scale over a 2-week period. A generalised estimating equation analysis was used to examine the relationship between daily pain intensity levels and weather in three different time epochs (current day, previous day, and change between previous and current days). A second model was adjusted for important back pain prognostic factors. The analysis did not show any association between weather and pain intensity levels in patients with acute LBP in each of the time epochs. There was no change in strength of association after the model was adjusted for prognostic factors. Contrary to common belief, the results demonstrated that the weather parameters of precipitation, temperature, relative humidity, and air pressure did not influence the intensity of pain reported by patients during an episode of acute LBP.
Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study
Central post-stroke pain is a neuropathic syndrome characterized by intolerable contralesional pain and, in rare cases, somatic delusions. To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain. Resting-state functional magnetic resonance imaging was used to assess the neurological effects of this treatment. Following vestibular stimulation we observed impressive improvements in motor skills, pain, and somatic delusions. In the functional connectivity study before the vestibular stimulation, we observed differences in the patient's left thalamus functional connectivity, with respect to the thalamus connectivity of a control group (N = 20), in the bilateral cingulate cortex and left insula. After the caloric stimulation, the left thalamus functional connectivity with these regions, which are known to be involved in the cortical response to pain, disappeared as in the control group. The beneficial use of vestibular stimulation in the reduction of pain and somatic delusion in a CPSP patient is now documented by behavioral and imaging data. This evidence can be applied to theoretical models of pain and body delusions. PMID:27028404
Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study.
Spitoni, Grazia Fernanda; Pireddu, Giorgio; Galati, Gaspare; Sulpizio, Valentina; Paolucci, Stefano; Pizzamiglio, Luigi
Central post-stroke pain is a neuropathic syndrome characterized by intolerable contralesional pain and, in rare cases, somatic delusions. To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain. Resting-state functional magnetic resonance imaging was used to assess the neurological effects of this treatment. Following vestibular stimulation we observed impressive improvements in motor skills, pain, and somatic delusions. In the functional connectivity study before the vestibular stimulation, we observed differences in the patient's left thalamus functional connectivity, with respect to the thalamus connectivity of a control group (N = 20), in the bilateral cingulate cortex and left insula. After the caloric stimulation, the left thalamus functional connectivity with these regions, which are known to be involved in the cortical response to pain, disappeared as in the control group. The beneficial use of vestibular stimulation in the reduction of pain and somatic delusion in a CPSP patient is now documented by behavioral and imaging data. This evidence can be applied to theoretical models of pain and body delusions.
Derivatives of furanditerpenes from Pterodon genus: Pharmacological studies disclose their potential as chronic pain relief in mice.
Spindola, Humberto M; Grando, Rogério; Figueiredo, Mariana C; Basting, Rosana; Queiroz, N C A; de Fátima, Ângelo; de Carvalho, João E; Wang, Zaijie J; Foglio, M A
Pterodon genus fruits are commercially available at the Brazilian medicinal market used in folk medicine due to their anti-inflammatory, analgesic, and anti-rheumatic effects. Previous studies demonstrated that furanditerpenes possessing vouacapan skeleton, isolated from Pterodon genus, possess expressive antinociceptive activities, with promising moiety for the development of new analgesic products. The antinociceptive properties of compounds 6α,7β-6α-hidroxivouacapan-7β-17β-lactone (HVL) and 6α-oxovouacapan-7β-17β-lactone (OVL), semi-synthetic analogues of furanditerpenes previously reported as analgesic agents were evaluated on animal experimental models (Spindola et al., 2010, 2011). The chemical-induced pain methods used in the present work, demonstrated for the first time that both compounds HVL and OVL have potential as important templates for the development of chronic pain control drugs. The main findings of this work were that both compounds were: effective in the writhing test; reduced paw edema in the carrageenan test; effective in the inflammatory phase of the formalin test corroborating their activity against inflammatory pain conditions; effective on reducing pain through the stimulation of vanilloid receptors sensible to capsaicin (an important pathway for chronic pain maintenance); reduced the pain stimulus caused by PGE2 injection (a pathway involved in chronic pain hypersensitivity); effective on decreasing mechanical allodynia in the CFA-model, demonstrating their potential use against chronic pain disorders.
Physiological and Psychological Predictors of Short-Term Disability in Workers with a History of Low Back Pain: A Longitudinal Study
Dubois, Jean-Daniel; Cantin, Vincent; Piché, Mathieu; Descarreaux, Martin
Despite an elusive pathophysiology, common characteristics are often observed in individuals with chronic low back pain (LBP). These include psychological symptoms, altered pain perception, altered pain modulation and altered muscle activation. These factors have been explored as possible determinants of disability, either separately or in cross-sectional studies, but were never assessed in a single longitudinal study. Therefore, the objective was to determine the relative contribution of psychological and neurophysiological factors to future disability in individuals with past LBP. The study included two experimental sessions (baseline and six months later) to assess cutaneous heat pain and pain tolerance thresholds, pain inhibition, as well as trunk muscle activation. Both sessions included the completion of validated questionnaires to determine clinical pain, disability, pain catastrophizing, fear-avoidance beliefs and pain vigilance. One hundred workers with a history of LBP and 19 healthy individuals took part in the first experimental session. The second experimental session was exclusively conducted on workers with a history of LBP (77/100). Correlation analyses between initial measures and disability at six months were conducted, and measures significantly associated with disability were used in multiple regression analyses. A first regression analysis showed that psychological symptoms contributed unique variance to future disability (R2 = 0.093, p = .009). To control for the fluctuating nature of LBP, a hierarchical regression was conducted while controlling for clinical pain at six months (R2 = 0.213, p < .001) where pain inhibition contributed unique variance in the second step of the regression (R2 change = 0.094, p = .005). These results indicate that pain inhibition processes may constitute potential targets for treatment to alleviate future disability in individuals with past or present LBP. Then again, the link between psychological symptoms and
Antihyperalgesic Effect of Hesperidin Improves with Diosmin in Experimental Neuropathic Pain.
Carballo-Villalobos, Azucena I; González-Trujano, María-Eva; Pellicer, Francisco; López-Muñoz, Francisco J
Neuropathic pain is caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or central nervous system. In this study, we investigated the hesperidin antihyperalgesic effects alone or combined with diosmin in a model of neuropathic pain to corroborate a possible synergistic antinociceptive activity. Mechanical and thermal hyperalgesia were assessed in the aesthesiometer and plantar tests, respectively, after chronic constriction injury (CCI) model in rats receiving hesperidin (HS, 5 doses from 10 to 1000 mg/kg) alone or combined with diosmin (DS, 10 and 100 mg/kg) in comparison to gabapentin (31.6 mg/kg). UHPLC-MS analysis of cerebral samples was used to recognize the central concentrations of these flavonoids. Participation of different receptors was also investigated in the presence of haloperidol, bicuculline, and naloxone antagonists. Acute hesperidin administration significantly decreased mechanical and thermal hyperalgesia in CCI rats. Antihyperalgesic response of hesperidin, improved by a combination with diosmin (DS10/HS100) in both stimuli, was blockaded by haloperidol, bicuculline, and naloxone, but not WAY100635, antagonists. Both flavonoids were detected in brain samples. In conclusion, hesperidin alone and combined with diosmin produces antihyperalgesic response in the CCI model in rats. Antihyperalgesic effect of DS10/HS100 combination involves central activity partially modulated by D2, GABAA, and opioids, but not by 5-HT1A, receptors.
Antihyperalgesic Effect of Hesperidin Improves with Diosmin in Experimental Neuropathic Pain
Pellicer, Francisco; López-Muñoz, Francisco J.
Neuropathic pain is caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or central nervous system. In this study, we investigated the hesperidin antihyperalgesic effects alone or combined with diosmin in a model of neuropathic pain to corroborate a possible synergistic antinociceptive activity. Mechanical and thermal hyperalgesia were assessed in the aesthesiometer and plantar tests, respectively, after chronic constriction injury (CCI) model in rats receiving hesperidin (HS, 5 doses from 10 to 1000 mg/kg) alone or combined with diosmin (DS, 10 and 100 mg/kg) in comparison to gabapentin (31.6 mg/kg). UHPLC-MS analysis of cerebral samples was used to recognize the central concentrations of these flavonoids. Participation of different receptors was also investigated in the presence of haloperidol, bicuculline, and naloxone antagonists. Acute hesperidin administration significantly decreased mechanical and thermal hyperalgesia in CCI rats. Antihyperalgesic response of hesperidin, improved by a combination with diosmin (DS10/HS100) in both stimuli, was blockaded by haloperidol, bicuculline, and naloxone, but not WAY100635, antagonists. Both flavonoids were detected in brain samples. In conclusion, hesperidin alone and combined with diosmin produces antihyperalgesic response in the CCI model in rats. Antihyperalgesic effect of DS10/HS100 combination involves central activity partially modulated by D2, GABAA, and opioids, but not by 5-HT1A, receptors. PMID:27672659
A Prospective Cohort Study Evaluating the Ability of Anticipated Pain, Perceived Analgesic Needs, and Psychological Traits to Predict Pain and Analgesic Usage following Cesarean Delivery.
Carvalho, Brendan; Zheng, Ming; Harter, Scott; Sultan, Pervez
Introduction. This study aimed to determine if preoperative psychological tests combined with simple pain prediction ratings could predict pain intensity and analgesic usage following cesarean delivery (CD). Methods. 50 healthy women undergoing scheduled CD with spinal anesthesia comprised the prospective study cohort. Preoperative predictors included 4 validated psychological questionnaires (Anxiety Sensitivity Index (ASI), Fear of Pain (FPQ), Pain Catastrophizing Scale, and Eysenck Personality Questionnaire) and 3 simple ratings: expected postoperative pain (0-10), anticipated analgesic threshold (0-10), and perceived analgesic needs (0-10). Postoperative outcome measures included post-CD pain (combined rest and movement) and opioid used for the 48-hour study period. Results. Bivariate correlations were significant with expected pain and opioid usage (r = 0.349), anticipated analgesic threshold and post-CD pain (r = -0.349), and perceived analgesic needs and post-CD pain (r = 0.313). Multiple linear regression analysis found that expected postoperative pain and anticipated analgesic needs contributed to post-CD pain prediction modeling (R (2) = 0.443, p < 0.0001); expected postoperative pain, ASI, and FPQ were associated with opioid usage (R (2) = 0.421, p < 0.0001). Conclusion. Preoperative psychological tests combined with simple pain prediction ratings accounted for 44% and 42% of pain and analgesic use variance, respectively. Preoperatively determined expected postoperative pain and perceived analgesic needs appear to be useful predictors for post-CD pain and analgesic requirements.
Indomethacin submicron particle capsules provide effective pain relief in patients with acute pain: a phase 3 study.
Altman, Roy; Daniels, Stephen; Young, Clarence L
Although frequently prescribed to relieve acute pain in patients, non-steroidal anti-inflammatory drugs (NSAIDs) are associated with dose-related gastrointestinal, cardiovascular, and renal complications. Investigational, submicron particle NSAIDs are being developed that could provide effective pain relief at lower doses than currently available oral NSAIDs. This is the first phase 3 study evaluating the analgesic efficacy and safety of lower-dose indomethacin submicron particle capsules in patients following elective surgery. This multicenter, double-blind study enrolled patients aged 18 to 68 years who underwent bunionectomy under regional anesthesia. Patients with a pain intensity rating of ≥40 mm on a 100-mm Visual Analog Scale were randomized to receive indomethacin submicron particle capsules (40 mg 3 times daily [TID], 40 mg twice daily [BID], or 20 mg TID), celecoxib (400 mg loading dose, then 200 mg BID), or placebo. The primary efficacy parameter was the overall (summed) pain intensity difference measured by a Visual Analog Scale during a period of 48 hours. Scheduled assessments measured secondary efficacy parameters such as patient pain intensity differences. Indomethacin submicron particle capsules 40 mg 3 times daily (509.6 ± 91.9 overall [summed] pain intensity difference), 40 mg twice daily (328.0 ± 92.9 overall [summed] pain intensity difference), and 20 mg 3 times daily (380.5 ± 92.9 overall [summed] pain intensity difference) reduced pain intensity from 0 to 48 hours (P ≤ 0.046 for all 3 groups) compared with placebo (67.8 ± 91.4 overall [summed] pain intensity difference). There was some evidence of patient analgesia for celecoxib (279.4 ± 91.9 overall [summed] pain intensity difference; P = 0.103). Some evidence of pain control was observed in patients as early as 2 hours following administration of indomethacin submicron particle capsules and was sustained throughout the treatment period. Indomethacin submicron particle capsules were
Socioeconomic variations in responses to chest pain: qualitative study
Richards, Helen Mary; Reid, Margaret Elspeth; Watt, Graham Charles Murray
Objective To explore and explain socioeconomic variations in perceptions of and behavioural responses to chest pain. Design Qualitative interviews. Setting Community based study in Glasgow, Scotland. Participants 30 respondents (15 men and 15 women) from a socioeconomically deprived area of Glasgow and 30 respondents (15 men and 15 women) from an affluent area of Glasgow. Outcome measures Participants' reports of their perceptions of and actions in response to chest pain. Results Residents of the deprived area reported greater perceived vulnerability to heart disease, stemming from greater exposure to heart disease in family members and greater identification with high risk groups and stereotypes of cardiac patients. This greater perceived vulnerability was not associated with more frequent reporting of presenting to a general practitioner. People from the deprived area reported greater exposure to ill health, which allowed them to normalise their chest pain, led to confusion with other conditions, and gave rise to a belief that they were overusing medical services. These factors were associated with a reported tendency not to present with chest pain. Anxiety about presenting among respondents in the deprived area was heightened by self blame and fear that they would be chastised by their general practitioner for their risk behaviours. Conclusions Important socioeconomic variations in responses to chest pain may contribute to the known inequities in uptake of secondary cardiology services. Primary care professionals and health promoters should be aware of the ways in which perceptions of symptoms and illness behaviour are shaped by social and cultural factors. What is already known on this topicSocioeconomic variations in rates of angiography and revascularisation existAmong socioeconomically deprived patients with a diagnosis of angina, barriers to accessing services include fear, denial, low expectations, and diagnostic confusionWhat this study adds
[Quality control in the therapy of chronic pain. Results obtained by a task force of the German Section of the International Association for the Study of Pain on psychological assessment of chronic pain. XI. Assessment and multiaxial classification of pain].
Klinger, R; Denecke, H; Glier, B; Kröner-Herwig, B; Nilges, P; Redegeld, M; Weiss, L
This paper reviews instruments in German language for the psychological assessment and classification of pain. Usually chronic pain syndromes are classified within the International Classification of Diseases (ICD). Instead of the psychiatric chapter of the ICD, it is possible to use the Diagnostic and Statistical Manual of Mental Disorders (DSM). The proposed classification system of the International Association of the Study of Pain (IASP) is based on a multiaxial solution. The numerous ways to classify chronic pain include many problems and limits, especially in the case of an interdisciplinary assessment. They provide no specific system for classifying pain syndromes. They are impractical to handle and restrict classifying pain as either somatogenic or psychogenic. It is not possible to describe both sides in one diagnosis without loss of information. As a result of this situation, a task force of the German Chapter of the International Association for the Study of Pain developed a Multiaxial Classification of Pain (Multiaxiale Schmerzklassifikation; MASK) as an advanced system of pain assessment and an alternative to the common classification systems. MASK embraces a somatic (MASK-S) and a psychological (MASK-P) part. Both parts constitute an 'interdisciplinary diagnosis'. MASK-S enables classifying a pain syndrome using hierarchical levels, with progredient specific degrees of differentiation. In addition there are 6 axes to describe pain syndromes qualitatively and quantitatively (e.g. localization, quality). The psychosocial part (MASK-P) embraces 5 main levels (1. behavioral, 2. emotional, 3. cognitive, 4. stress-related, 5. habitual personal factors) and 2 additional levels (6. functional coherence, 7. ICD/DSM-diagnosis additional). The MASK-P part of the diagnosis is composed of graduation on these levels. Differential axis of the pain syndromes are described phenomenologically and specifically. MASK provides the possibility of establishing an
Acupuncture Treatment of Lateral Elbow Pain: A Nonrandomized Pilot Study
Liu, Yan-Song; Gadau, Marcus; Zhang, Guo-Xue; Liu, Hao; Wang, Fu-Chun; Zaslawski, Christopher; Li, Tie; Tan, Yuan-Sheng; Berle, Christine; Li, Wei-Hong; Bangrazi, Sergio; Liguori, Stefano; Zhang, Shi-Ping
In planning for a large-scale multicenter trial to evaluate the effect of acupuncture for the treatment of lateral elbow pain, a pilot study was conducted. This was a prospective, investigator- and patient-blinded, nonrandomized, placebo controlled trial. Subjects were evaluated at baseline, before fourth, seventh, and ninth treatment, and at a two-week posttreatment follow-up. The treatment group received unilateral acupuncture at LI 10 and LI 11 at the affected side with manual needle manipulation; the control group received sham-laser acupuncture at the same acupoints. Measures included (i) disabilities of the arm, shoulder, and hand (DASH) questionnaire, (ii) pain-free grip strength (PFGS), and (iii) a visual analogue scale (VAS) for pain. Significant differences in DASH score, PFGS, and VAS between treatment and control group were found at the ninth treatment (n = 20 for each group, P < 0.05). Only DASH showed significant differences compared to the control for all the measurement time points after treatment commenced and appears to be a sensitive and appropriate primary outcome measure for the future multisite trial. Results from this pilot study provided relevant information about treatment efficacy, credibility of control treatment, and sensitivity of different outcome measures for the planning of the future trial. PMID:27006679
Natural course of acute neck and low back pain in the general population: the HUNT study.
Vasseljen, Ottar; Woodhouse, Astrid; Bjørngaard, Johan Håkon; Leivseth, Linda
In this prospective cohort study we aimed to describe the natural course of acute neck and low back pain in a general population of Norway. We screened 9056 subjects aged 20-67 years who participated in a general health survey for a new episode of neck or low back pain the previous month. The screening identified 219 subjects who formed the cohort for this study. Pain intensity was reported on a numeric rating scale (0-10) at 1, 2, 3, 6, and 12 months after start of the new pain episode. The course of pain was described for neck and low back pain, different baseline pain levels, age groups, and number of pain sites at baseline. Use of medication and health care was described and associations between pain intensity and seeking health care were estimated. Pain declined rapidly within 1 month after a new pain episode, with a reduction of 0.91 (95% confidence interval [CI] 0.50-1.32) for neck pain and 1.40 (95% CI 0.82-1.99) for low back pain with little change thereafter. However, pain remained unchanged over the follow-up year for those with equal pain in the neck and low back areas at baseline and for those reporting 4 or more pain sites at baseline. Only 1 in 5 sought health care for their complaints. Still, the course of pain was comparable to effect sizes reported in interventional studies. This study thus contributes natural course reference data for comparisons of pain outcome in clinical trials and practice.
Experimental Infrasound Studies in Nevada
NASA Astrophysics Data System (ADS)
Herrin, E. T.; Negraru, P. T.; Golden, P.; Williams, A.
An experimental propagation study was carried out in Nevada in June 2009 on Julian days 173-177. During this field experiment we deployed 16 single channel digital infrasound recorders to monitor the munitions disposal activities near Hawthorne, NV. The sensors were deployed in a single line and placed approximately 12 km apart at distances ranging from 2 to 177 km. A four element semi-permanent infrasound array named FNIAR was installed approximately 154 km north of the detonation site in line with the individual temporary recorders. Tropospheric arrivals were observed during all days of the experiment, but during day 176 the observed arrivals had very large amplitudes. A large signal was observed at 58 km from the detonation site with amplitude as large as 4 Pascals, while at 94 km no signal was observed. At FNIAR the amplitude of the tropospheric arrival was 1 Pascal. During this day meteorological data acquired in the propagation path showed a strong jet stream to the north. On day 177 we were not able to identify tropospheric arrivals beyond 34 km, but at stations beyond 152 km we observed stratospheric arrivals. Continuous monitoring of these signals at FNIAR shows that stratospheric arrivals are the most numerous. In a two month period, from 06/15/2009 to 08/15/2009 there were 35 operational days at the Hawthorne disposal facility resulting in 212 explosions with known origin times. Based on the celerity values there were 115 explosions that have only stratospheric arrivals (celerities of 300-275 m/s), 72 explosions with both tropospheric (celerities above 330 m/s) and stratospheric arrivals, 20 explosions that were not detected and five explosions that have only tropospheric arrivals.
Studies of Properties of Pain Networks as Predictors of Targets of Stimulation for Treatment of Pain
H. (1999). Dissociation of sensory and affective dimensions of pain using hypnotic modulation. Pain 82, 159–171. Rasche, D., Rinaldi, P. C., Young, R...distribution, and reproduction in other forums, pro- vided the original authors and source are credited. Frontiers in Integrative Neuroscience www.frontiersin.org December 2011 | Volume 5 | Article 80 | 7
Participation of neuronal nitric oxide synthase in experimental neuropathic pain induced by sciatic nerve transection.
Chacur, M; Matos, R J B; Alves, A S; Rodrigues, A C; Gutierrez, V; Cury, Y; Britto, L R G
Nerve injury leads to a neuropathic pain state that results from central sensitization. This phenomenom is mediated by NMDA receptors and may involve the production of nitric oxide (NO). In this study, we investigated the expression of the neuronal isoform of NO synthase (nNOS) in the spinal cord of 3-month-old male, Wistar rats after sciatic nerve transection (SNT). Our attention was focused on the dorsal part of L3-L5 segments receiving sensory inputs from the sciatic nerve. SNT resulted in the development of neuropathic pain symptoms confirmed by evaluating mechanical hyperalgesia (Randall and Selitto test) and allodynia (von Frey hair test). Control animals did not present any alteration (sham-animals). The selective inhibitor of nNOS, 7-nitroindazole (0.2 and 2 microg in 50 microL), blocked hyperalgesia and allodynia induced by SNT. Immunohistochemical analysis showed that nNOS was increased (48% by day 30) in the lumbar spinal cord after SNT. This increase was observed near the central canal (Rexed's lamina X) and also in lamina I-IV of the dorsal horn. Real-time PCR results indicated an increase of nNOS mRNA detected from 1 to 30 days after SNT, with the highest increase observed 1 day after injury (1469%). Immunoblotting confirmed the increase of nNOS in the spinal cord between 1 and 15 days post-lesion (20%), reaching the greatest increase (60%) 30 days after surgery. The present findings demonstrate an increase of nNOS after peripheral nerve injury that may contribute to the increase of NO production observed after peripheral neuropathy.
Management of severe lower abdominal or inguinal pain in high-performance athletes. PAIN (Performing Athletes with Abdominal or Inguinal Neuromuscular Pain Study Group).
Meyers, W C; Foley, D P; Garrett, W E; Lohnes, J H; Mandlebaum, B R
The purpose of this study was to gain insight into the pathophysiologic processes of severe lower-abdominal or inguinal pain in high-performance athletes. We evaluated 276 patients; 175 underwent pelvic floor repairs. Of the 157 athletes who had not undergone previous surgery, 124 (79%) participated at a professional or other highly competitive level, and 138 patients (88%) had adductor pain that accompanied the lower-abdominal or inguinal pain. More patients underwent related adductor releases during the later operative period in the series. Evaluation revealed 38 other abnormalities, including severe hip problems and malignancies. There were 152 athletes (97%) who returned to previous levels of performance. The syndrome was uncommon in women and the results were less predictable in nonathletes. A distinct syndrome of lower-abdominal/adductor pain in male athletes appears correctable by a procedure designed to strengthen the anterior pelvic floor. The location and pattern of pain and the operative success suggest the cause to be a combination of abdominal hyperextension and thigh hyperabduction, with the pivot point being the pubic symphysis. Diagnosis of "athletic pubalgia" and surgery should be limited to a select group of high-performance athletes. The consideration of other causes of groin pain in the patient is critical.
Elkins, Gary R.; Koep, Lauren L.; Kendrick, Cassie E.
Loin pain hematuria is characterized by chronic loin pain, hematuria, and dysuria. There are no known effective treatments for loin pain hematuria and longer-term use of analgesics and surgical options are often ineffective or associated with negative side effects. This article reports on a 17-year-old female patient diagnosed with loin pain hematuria who presented with unilateral, uncontrolled loin pain following numerous unsuccessful attempts at controlling her symptoms with traditional medical interventions—including antibiotics, opioids, and renal denervation. The patient received 8 sessions of hypnotherapy. Baseline, end-point, and follow-up measures administered included the General Health Questionnaire, Hospital Anxiety and Depression Scale, McGill Pain Questionnaire, Pain Discomfort Scale, and visual analogue measures of pain, academic interference, and social interference. At follow-up, results indicated clinically significant decreases in pain, anxiety, and depression with nearly complete remission of presenting symptoms. PMID:22098573
Underestimation and undertreatment of pain in HIV disease: multicentre study.
Larue, F.; Fontaine, A.; Colleau, S. M.
OBJECTIVE: To measure the prevalence, severity, and impact of pain on quality of life for HIV patients; to identify factors associated with undertreatment of pain. DESIGN: Multicentre cross sectional survey. SETTINGS: 34 HIV treatment facilities, including inpatient hospital wards, day hospitals, and ambulatory care clinics, in 13 cities throughout France. SUBJECTS: 315 HIV patients at different stages of the disease. MAIN OUTCOME MEASURES: Patients: recorded presence and severity of pain and rated quality of life. Doctors: reported disease status, estimate of pain severity, and analgesic treatment ordered. RESULTS: From 30% (17/56) of outpatients to 62% (73/118) of inpatients reported pain due to HIV disease. Pain severity significantly decreased patients' quality of life. Doctors underestimated pain severity in 52% (70/135) of HIV patients reporting pain. Underestimation of pain severity was more likely for patients who reported moderate (odds ratio 24) or severe pain (165) and less likely for patients whose pain source was identified or who were perceived as more depressed. Of the patients reporting moderate or severe pain, 57% (61/107) did not receive any analgesic treatment; only 22% (23/107) received at least weak opioids. Likelihood of analgesic prescription increased when doctors estimated pain to be more severe and regarded patients as sicker. CONCLUSIONS: Pain is a common and debilitating symptom of HIV disease which is gravely underestimated and undertreated. PMID:9001475
Association between Pain in Adolescence and Low Back Pain in Adulthood: Studying a Cohort of Mine Workers
Jonsson, David; Burström, Lage; Nilsson, Tohr; Wahlström, Jens
Purpose. To study the association of self-reported pain in adolescence with low back pain (LBP) in adulthood among mine workers and, also, study associations between the presence of LBP over 12-month or one-month LBP intensity during a health examination and daily ratings of LBP three and nine months later. Methods. Mixed design with data collected retrospectively, cross-sectionally, and prospectively. Data was collected using a questionnaire during a health examination and by using self-reported daily ratings of LBP three and nine months after the examination. Results. Pain prevalence during teenage years was 55% and it was 59% at age 20. Pain during teenage years had a relative risk of 1.33 (95% confidence interval 1.03–1.73) of LBP 12 months prior to the health examination, but with no associations with LBP intensity or LBP assessed by text messaging. Pain at age 20 years was not associated with any measure of LBP in adulthood. Daily ratings of LBP were associated with LBP during the health examination three and nine months earlier. Conclusions. There were no clear associations between self-reported pain in adolescence and LBP in adulthood. Self-reported daily ratings of LBP were associated with LBP from the health examination. Possible limitations for this study were the retrospective design and few participants. PMID:28367328
The Efficacy of Thermotherapy and Cryotherapy on Pain Relief in Patients with Acute Low Back Pain, A Clinical Trial Study
Dehghan, Morteza
Introduction: Acute low back pain is one of the most common health problems especially in industrialized countries where 75 per cent of the population develop it at least once during their life. This study examined the efficacy of thermotherapy and cryotherapy, alongside a routine pharmacologic treatment, on pain relief in patients with acute low back pain referring an orthopedic clinic in Shahrekord, Iran. Materials and Methods: This clinical trial study was conducted on 87 patients randomly assigned to three (thermotherapy and cryotherapy as intervention, and naproxen as control) groups of 29 each. The first (thermotherapy) group underwent treatment with hot water bag and naproxen, the second (cryotherapy) group was treated with ice and naproxen, and the naproxen group was only treated with naproxen, all for one week. All patients were examined on 0, 3rd, 8th, and 15th day after the first visit and the data gathered by McGill Pain Questionnaire. The data were analyzed by SPSS software using paired t-test, ANOVA, and chi-square. Results: In this study, mean age of the patients was 34.48 (20–50) years and 51.72 per cent were female. Thermotherapy patients reported significantly less pain compared to cryotherapy and control (p≤0.05). In thermotherapy and cryotherapy groups, mean pain in the first visit was 12.70±3.7 and 12.06±2.6, and on the 15th day after intervention 0.75±0.37 and 2.20±2.12, respectively. Conclusion: The results indicated that the application of thermo–therapy and cryotherapy accompanied with a pharmacologic treatment could relieve pain in the patients with acute low back pain. PMID:25386469
The "at-home LLLT" in temporo-mandibular disorders pain control: a pilot study
Pelosi, A; Queirolo, V; Vescovi, P; Merigo, E
Objectives: The Temporo-Mandibular Disorders (TMD) are a set of dysfunctional patterns concerning the temporo-mandibular joints (TMJ) and the masticatory muscles; its main symptom is pain, probably caused by inflammatory changes in the synovial membrane, alterations in the bone marrow of the mandibular condyle and impingement and compression. The aim of this preliminary study was to investigate the effectiveness in the TMD pain reduction of a new laser device recently proposed by the commerce that, due to its reduced dimensions and to be a class I laser according the ANSI classification, may be used at home by the patient himself. Material and methods: Twenty-four patients with TMD were randomly selected: the inclusion criteria for the sample was the diagnosis of mono- or bi-lateral TMD, with acute pain restricted to the joint area, associated with the absence of any muscle tenderness during palpation. The patients were randomly assigned to two groups: Group 1 (12 patients): patients receiving real LLLT (experimental group). Group 2 (12 patients): patients receiving inactive laser (placebo group). The treatment was performed once a day for two weeks with an 808 nm diode laser by the patient himself with irradiation of the cutaneous zone corresponding to the TMJ for 15 minutes each side. Each patient was instructed to express its pain in a visual analogue scale (VAS) making a perpendicular line between the two extremes representing the felt pain level. Statistical analysis was realized with GraphPad Instat Software, where P<0.05 was considered significant and P<0.01 very significant. Results: The patient's pain evaluation was expressed in the two study groups before the treatment, 1 week and two weeks after the treatment. The differences between the two groups result extremely significant with p<0.0001 for the comparison of VAS value after 1 and 2 weeks. Conclusion: This study, even if it may be considered such a pilot study, investigated a new way to control the
Characterizing abdominal pain in IBS: guidance for study inclusion criteria, outcome measurement and clinical practice
Spiegel, B. M. R.; Bolus, R.; Harris, L. A.; Lucak, S.; Chey, W. D.; Sayuk, G.; Esrailian, E.; Lembo, A.; Karsan, H.; Tillisch, K.; Talley, J.; Chang, L.
SUMMARY Background Although irritable bowel syndrome (IBS) is a multisymptom disorder, abdominal pain drives illness severity more than other symptoms. Despite consensus that IBS trials should measure pain to define study entry and determine efficacy, the optimal method of measuring pain remains uncertain. Aim To determine whether combining information from multiple pain dimensions may capture the IBS illness experience more effectively than the approach of measuring `pain predominance' or pain intensity alone. Methods Irritable bowel syndrome patients rated dimensions of pain, including intensity, frequency, constancy, predominance, predictability, duration, speed of onset and relationship to bowel movements. We evaluated the impact of each dimension on illness severity using multivariable regression techniques. Results Among the pain dimensions, intensity, frequency, constancy and predictability were strongly and independently associated with illness severity; the other dimensions had weaker associations. The clinical definition of `pain predominance', in which patients define pain as their most bothersome symptom, was insufficient to categorize patients by illness severity. Conclusions Irritable bowel disease pain is multifaceted; some pain dimensions drive illness more than others. IBS trials should measure various pain dimensions, including intensity, constancy, frequency and predictability; this may improve upon the customary use of measuring pain as a unidimensional symptom in IBS. PMID:20807217
Chronic pain in the Republic of Ireland--community prevalence, psychosocial profile and predictors of pain-related disability: results from the Prevalence, Impact and Cost of Chronic Pain (PRIME) study, part 1.
Raftery, Miriam N; Sarma, Kiran; Murphy, Andrew W; De la Harpe, Davida; Normand, Charles; McGuire, Brian E
The aims of the PRIME study (Prevalence, Impact and Cost of Chronic Pain) were 3-fold: (1) to determine the point prevalence of chronic pain in Ireland; (2) to compare the psychological and physical health profiles of those with and without chronic pain; and (3) to explore a predictive model of pain-related disability. A postal survey of 3136 people was conducted with a representative community-based sample of adults. Measures were obtained for sociodemographic variables, physical and psychological well-being, depressive symptoms, presence of pain, pain severity, pain-related disability, and illness perceptions. Responses were received from 1204 people. The prevalence of chronic pain was 35.5% (95% CI=32.8-38.2) (n=428). No gender difference in prevalence was found. Prevalence of pain increased with age and was associated with manual employment. The most commonly reported site of pain was the lower back (47.6%); however, multiple pain sites was the norm, with more than 80% of participants reporting more than 1 pain site. Approximately 12% of participants were unable to work or were on reduced work hours because of pain. Of those with chronic pain, 15% met the criteria for clinically relevant depression compared with 2.8% of those without pain. A multiple regression analysis, predicting 67% of variance, showed that pain intensity was the strongest predictor of pain-related disability. Depression and illness perceptions were also predictive of pain-related disability, after controlling for the effects of pain intensity. Chronic pain is a prevalent health problem in Ireland and is associated with significant psychological and functional disability. Psychological factors appear to influence the level of pain-related disability.
One night of total sleep deprivation promotes a state of generalized hyperalgesia: a surrogate pain model to study the relationship of insomnia and pain.
Schuh-Hofer, Sigrid; Wodarski, Rachel; Pfau, Doreen B; Caspani, Ombretta; Magerl, Walter; Kennedy, Jeffrey D; Treede, Rolf-Detlef
Sleep disturbances are highly prevalent in chronic pain patients. Understanding their relationship has become an important research topic since poor sleep and pain are assumed to closely interact. To date, human experimental studies exploring the impact of sleep disruption/deprivation on pain perception have yielded conflicting results. This inconsistency may be due to the large heterogeneity of study populations and study protocols previously used. In addition, none of the previous studies investigated the entire spectrum of nociceptive modalities. To address these shortcomings, a standardized comprehensive quantitative sensory protocol was used in order to compare the somatosensory profile of 14 healthy subjects (6 female, 8 male, 23.5 ± 4.1 year; mean ± SD) after a night of total sleep deprivation (TSD) and a night of habitual sleep in a cross-over design. One night of TSD significantly increased the level of sleepiness (P<0.001) and resulted in higher scores of the State Anxiety Inventory (P<0.01). In addition to previously reported hyperalgesia to heat (P<0.05) and blunt pressure (P<0.05), study participants developed hyperalgesia to cold (P<0.01) and increased mechanical pain sensitivity to pinprick stimuli (P<0.05) but no changes in temporal summation. Paradoxical heat sensations or dynamic mechanical allodynia were absent. TSD selectively modulated nociception, since detection thresholds of non-nociceptive modalities remained unchanged. Our findings show that a single night of TSD is able to induce generalized hyperalgesia and to increase State Anxiety scores. In the future, TSD may serve as a translational pain model to elucidate the pathomechanisms underlying the hyperalgesic effect of sleep disturbances.
Ingvar, M
Functional neuroimaging has fundamentally changed our knowledge about the cerebral representation of pain. For the first time it has been possible to delineate the functional anatomy of different aspects of pain in the medial and lateral pain systems in the brain. The rapid developments in imaging methods over the past years have led to a consensus in the description of the central pain responses between different studies and also to a definition of a central pain matrix with specialized subfunctions in man. In the near future we will see studies where a systems perspective allows for a better understanding of the regulatory mechanisms in the higher-order frontal and parietal cortices. Also, pending the development of experimental paradigms, the functional anatomy of the emotional aspects of pain will become better known. PMID:10466155
Neuropathic Pain in Elderly Patients with Chronic Low Back Painand Effects of Pregabalin: A Preliminary Study
Ito, Kenyu; Hida, Tetsuro; Ito, Sadayuki; Harada, Atsushi
Study Design Preliminary study. Purpose To assess the association of neuropathic pain with chronic low back pain (LBP) and the effect of pregabalin on neuropathic pain in the elderly. Overview of Literature Of those with chronic LBP, 37% were predominantly presenting with neuropathic pain in young adults. Pregabalin is effective for pain in patients with diabetic neuropathy and peripheral neuralgia. No study has reported on the effects of pregabalin for chronic LBP in elderly patients yet. Methods Pregabalin was administered to 32 patients (age, ≥65 years) with chronic LBP for 4 weeks. Pain and activities of daily living were assessed using the Neuropathic Pain Screening Questionnaire (NePSQ), the pain DETECT questionnaire, visual analog scale, the Japanese Orthopedic Association score, the short form of the McGill Pain Questionnaire and the Roland Morris Disability Questionnaire. Modic change and spinal canal stenosis were investigated using magnetic resonance imaging. Results Altogether, 43.3% of patients had neuropathic pain according to the NePSQ and 15.6% patients had pain according to the pain DETECT. The efficacy rate of pregabalin was 73.3%. A significant effect was observed in patients with neuropathic pain after 4 weeks of administration. Conclusions Neuropathic pain was slightly less frequently associated with chronic LBP in the elderly. Pregabalin was effective in reducing pain in patients with chronic LBP accompanied with neuropathic pain. Lumbar spinal stenosis and lower limb symptoms were observed in patients with neuropathic pain. We recommend the use of pregabalin for patients after evaluating a screening score, clinical symptoms and magnetic resonance imaging studies. PMID:25901238
Pain Reduction in Myofascial Pain Syndrome by Anodal Transcranial Direct Current Stimulation Combined with Standard Treatment: A Randomized Controlled Study
Sakrajai, Piyaraid; Janyacharoen, Taweesak; Jensen, Mark P.; Sawanyawisuth, Kittisak; Auvichayapat, Narong; Tunkamnerdthai, Orathai; Keeratitanont, Keattichai; Auvichayapat, Paradee
Background Myofascial pain syndrome (MPS) in the shoulder is among the most prevalent pain problems in the middle-aged population worldwide. Evidence suggests that peripheral and central sensitization may play an important role in the development and maintenance of shoulder MPS. Given previous research supporting the potential efficacy of anodal transcranial direct current stimulation (tDCS) for modulating pain-related brain activity in individuals with refractory central pain, we hypothesized that anodal tDCS when applied over the primary motor cortex (M1) combined with standard treatment will be more effective for reducing pain in patients with MPS than standard treatment alone. Method Study participants were randomized to receive either (1) standard treatment with 5-consecutive days of 1 mA anodal tDCS over M1 for 20 min or (2) standard treatment plus sham tDCS. Measures of pain intensity, shoulder passive range of motion, analgesic medication use, and self-reported physical functioning were administered before treatment and again at post-treatment and 1-, 2-, 3-and 4-week follow-up. Results Thirty-one patients with MPS were enrolled. Participants assigned to the active tDCS condition reported significantly more pre- to post-treatment reductions in pain intensity that were maintained at 1-week post-treatment, and significant improvement in shoulder adduction PROM at 1-week follow-up than participants assigned to the sham tDCS condition. Conclusion 5 consecutive days of anodal tDCS over M1 combined with standard treatment appears to reduce pain intensity, and may improve PROM, faster than standard treatment alone. Further tests of the efficacy and duration of effects of tDCS in the treatment of MPS are warranted. PMID:25373724
Study Suggests Brain Is Hard-Wired for Chronic Pain
... to predict whether a subject would recover from low back pain. Red dots represent differences in white matter structure ... may predict whether a person will suffer chronic low back pain, according to researchers who used brain scans. The ...
Common Painkillers Don't Ease Back Pain, Study Finds
... gastrointestinal problems. "There are other effective and safer strategies to manage spinal pain," said review author Gustavo Machado. He is a research fellow with the George Institute for Global Health in Sydney, Australia. Back and neck pain ...
The prevalence of chronic chest and leg pain following cardiac surgery: a historical cohort study.
Bruce, J; Drury, N; Poobalan, A S; Jeffrey, R R; Smith, W C S; Chambers, W A
Chronic pain after surgery is recognised as an important post-operative complication; recent studies have shown up to 30% of patients reporting persistent pain following mastectomy and inguinal hernia repair. No large-scale studies have investigated the epidemiology of chronic pain at two operative sites following coronary artery bypass grafting (CABG). This paper reports the follow-up of a cohort of 1348 patients who underwent cardiac surgery between 1996 and 2000 at one cardiothoracic unit in northeast Scotland. Chronic pain was defined as pain in the location of surgery, different from that suffered pre-operatively, arising post-operatively and persisting beyond 3 months. The survey questionnaire consisted of the short-form-36 (SF-36), Rose angina questionnaire, McGill pain questionnaire and the University of California and San Francisco (UCSF) pain service questionnaire. Of the 1080 responders, 130 reported chronic chest pain, 100 chronic post-saphenectomy pain and 194 reported pain at both surgical sites. The cumulative prevalence of post-cardiac surgery pain was 39.3% (CI(95) 36.4-42.2%) and mean time of 28 months since surgery (SD 15.3 months). Patients who reported pain at both sites had lower quality of life scores across all eight health domains compared to patients with pain at one site only and those who were pain-free. Prevalence of chronic pain decreased with age, from 55% in those aged under 60 years to 34% in patients over 70 years. Patients with pre-operative angina and those who were overweight or obese (BMI>/=25) at the time of surgery were more likely to report chronic pain. Chronic pain following median sternotomy and saphenous vein harvesting is more common than hitherto reported and that patients undergoing CABG should be warned of this possibility.
Meta-analysis of placebo responses in central neuropathic pain: impact of subject, study, and pain characteristics.
Cragg, Jacquelyn J; Warner, Freda M; Finnerup, Nanna Brix; Jensen, Mark P; Mercier, Catherine; Richards, John Scott; Wrigley, Paul; Soler, Dolors; Kramer, John L K
The placebo response is a complex construct related to psychobiological effects, as well as natural history and regression to the mean. Moreover, patient and study design characteristics have also been proposed as significantly affecting placebo responses. The aim of the current investigation was to identify factors that contribute to variable placebo responses in clinical trials involving individuals with central neuropathic pain. To this end, we performed a systematic review and meta-analysis of placebo-controlled trials examining pharmacological and noninvasive brain stimulation interventions for central neuropathic pain. Study design, subject characteristics, and pain ratings for the placebo group were extracted from each trial. Pooling of results and identification of moderating factors were carried out using random effects meta-analysis and meta-regression techniques. A total of 39 published trials met the inclusion criteria (spinal cord injury, n = 26; stroke, n = 6; multiple sclerosis, n = 7). No significant publication bias was detected. Overall, there was a significant effect for placebo to reduce central pain (-0.64, CI: -0.83 to -0.45). Smaller placebo responses were associated with crossover-design studies, longer pain duration, and greater between-subject baseline pain variability. There were no significant effects for neurological condition (stroke vs multiple sclerosis vs spinal cord injury) or the type of intervention (eg, pharmacological vs noninvasive brain stimulation). In a planned subanalysis, the severity of damage in the spinal cord also had no significant effect on the placebo response. Further study is warranted to identify factors that may explain the impact of pain duration on the placebo response at the individual subject level.
Pain Self-Management in HIV-infected Individuals with Chronic Pain: A Qualitative Study
Merlin, Jessica S.; Walcott, Melonie; Kerns, Robert; Bair, Matthew J.; Burgio, Kathryn L.; Turan, Janet M.
Objective Chronic pain in individuals with HIV is a common, impairing condition. Behavioral interventions for chronic pain specifically tailored to this population have yet to be developed. We assert that understanding self-management strategies already used by persons living with these conditions is an essential first step, and is the objective of this investigation. Design We conducted a thematic analysis of qualitative data from 25 in-depth interviews with individuals with HIV and chronic pain. Results The primary pain self-management strategies articulated by participants were: physical activity; cognitive and spiritual strategies; spending time with family and friends and social support; avoidance of physical/social activity; medication-centric pain management; and substance use. Conclusions Some of these strategies may be viewed as beneficial and overlap with known HIV self-management strategies (cognitive strategies), whereas others may have negative health consequences (substance use). Interventions that incorporate healthy self-management strategies may be particularly effective in improving both HIV and pain outcomes. PMID:25645646
Factorial Structure of the Pain Rehabilitation Expectations Scale: A Preliminary Study
ERIC Educational Resources Information Center
Cheing, Gladys L. Y.; Lai, Amy K. M.; Vong, Sinfia K. S.; Chan, Fong H.
The aim of this study was to report the preliminary validation results for the Pain Rehabilitation Expectations Scale (PRES). The PRES is a clinical tool developed to measure the expectations about rehabilitation treatment and outcome for people with back pain. Fifty people with chronic back pain were recruited from 11 physiotherapy outpatient…
A feasibility study of a combined nurse/pharmacist-led chronic pain clinic in primary care.
Briggs, Michelle; Closs, S José; Marczewski, Kath; Barratt, Joanne
Chronic pain is common and management hampered by lack of resources in primary and secondary care. Nurse- or pharmacist-led clinics have been shown to lead to improvements in care for patients with chronic pain. This study showed that a combined nurse/pharmacist-led clinic for managing chronic pain in primary care can lead to improvements in management of pain, reduction in use of secondary care resources and high rates of satisfaction.
The relationship between knowledge of pain neurophysiology and fear avoidance in people with chronic pain: A point in time, observational study.
Fletcher, Claire; Bradnam, Lynley; Barr, Christopher
Chronic pain is prevalent in the western world; however fear of pain often has a greater impact than the degree of initial injury. The aim of this study was to explore the relationship between knowledge of the neurophysiology of pain and fear avoidance in individuals diagnosed with chronic pain. Twenty-nine people with chronic musculoskeletal pain were recruited and completed questionnaires to determine their understanding of pain neurophysiology and the degree of their fear avoidance beliefs. There was an inverse relationship between knowledge of pain neurophysiology and the level of fear avoidance. Patients with higher pain knowledge reported less fear avoidance and lower perceived disability due to pain. There was no relationship with the educational level or compensable status for either variable. The findings suggest that fear avoidance is positively influenced by neurophysiology of pain education, so that a higher level of pain knowledge is associated with less activity-related fear. The clinical implication is that reducing fear avoidance/kinesiophobia using neurophysiology of pain education in people with chronic pain may provide an effective strategy to help manage fear avoidance and related disability in the chronic pain population in order to improve treatment outcomes.
Assessment of pain in less severely ill and injured aeromedical evacuation patients: a prospective field study.
Bridges, Elizabeth; Dukes, Susan; Serres, Jennifer
Pain management is vitally important to injured patients being evacuated from the warzone. A prospective assessment of real-time ratings of pain acceptability, intensity, and satisfaction of a convenience sample of 114 less severely ill and injured U.S. military patients being evacuated on Aeromedical Evacuation (AE) missions from Ramstein Air Field, Germany, to Andrews Air Force Base, Maryland, was conducted. Data were collected before and during 12 AE flights in December 2012 and May 2013. Acceptable pain intensity was a median of 6/10 (range 2-9), with 76% of patients indicating an acceptable pain intensity greater than 4. During AE transport, 75% of patients reported at least one pain score≥4. Despite these high pain ratings, there was documentation of administration for only 58% of routine and 48% for as-needed analgesics/adjuvants. Over 47% of patients experienced pain that exceeded their acceptable intensity level, but of those patients with pain that was more severe than acceptable, only 10% rated their satisfaction with their pain management as poor or fair. This is the first study to provide real-time concurrent assessment of pain and pain management during en route care. The worst pain was reported for the hospital to aircraft arrival, suggesting the need for interventions to safely optimize pain management during this handoff period.
Association between pain outcomes and race and opioid treatment: Retrospective cohort study of Veterans.
Burgess, Diana J; Gravely, Amy A; Nelson, David B; Bair, Matthew J; Kerns, Robert D; Higgins, Diana M; Farmer, Melissa M; Partin, Melissa R
We examined whether pain outcomes (pain interference, perceived pain treatment effectiveness) vary by race and then whether opioid use moderates these associations. These analyses are part of a retrospective cohort study among 3,505 black and 46,203 non-Hispanic, white Department of Veterans Affairs (VA) patients with diagnoses of chronic musculoskeletal pain who responded to the 2007 VA Survey of Healthcare Experiences of Patients (SHEP). We used electronic medical record data to identify prescriptions for pharmacologic pain treatments in the year after diagnosis (Pain Diagnosis index visit) and before the SHEP index visit (the visit that made one eligible to complete the SHEP); pain outcomes came from the SHEP. We found no significant associations between race and pain interference or perceived effectiveness of pain treatment. VA patients with opioid prescriptions between the Pain Diagnosis index visit and the SHEP index visit reported greater pain interference on the SHEP than those without opioid prescriptions during that period. Opioid prescriptions were not associated with perceived treatment effectiveness for most patients. Findings raise questions about benefits of opioids for musculoskeletal pain and point to the need for alternative treatments for addressing chronic noncancer pain.
Associations Between Vitamin D Status and Pain in Older Adults: The Invecchiare in Chianti Study
Hicks, Gregory E.; Shardell, Michelle; Miller, Ram R.; Bandinelli, Stefania; Guralnik, Jack; Cherubini, Antonio; Lauretani, Fulvio; Ferrucci, Luigi
OBJECTIVES To examine cross-sectional associations between vitamin D status and musculoskeletal pain and whether they differ by sex. DESIGN Population-based study of persons living in the Chianti geographic area (Tuscany, Italy). SETTING Community. PARTICIPANTS Nine hundred fifty-eight persons (aged ≥65) selected from city registries of Greve and Bagno a Ripoli. MEASUREMENTS Pain was categorized as mild or no pain in the lower extremities and back; moderate to severe back pain, no lower extremity pain; moderate to severe lower extremity pain, no back pain; and moderate to severe lower extremity and back pain (dual region). Vitamin D was measured according to radioimmunoassay, and deficiency was defined as 25-hydroxyvitamin D (25(OH)D) less than 25 nmol/L. RESULTS The mean age ± standard deviation was 75.1 ± 7.3 for women and 73.9 ± 6.8 for men. Fifty-eight percent of women had at least moderate pain in some location, compared with 27% of men. After adjusting for potential confounders, vitamin D deficiency was not associated with lower extremity pain or dual-region pain, although it was associated with a significantly higher prevalence of at least moderate back pain without lower extremity pain in women (odds ratio = 1.96, 95% confidence interval = 1.01–3.59) but not in men. CONCLUSION Lower concentrations of 25(OH)D are associated with significant back pain in older women but not men. Because vitamin D deficiency and chronic pain are fairly prevalent in older adults, these findings suggest it may be worthwhile to query older adults about their pain and screen older women with significant back pain for vitamin D deficiency. PMID:18331295
Impaired psychomotor ability and attention in patients with persistent pain: a cross-sectional comparative study
Gunnarsson, Helena; Grahn, Birgitta; Agerström, Jens
Background and aims Patients with pain have shown cognitive impairment across various domains. Although the pain qualities vary among patients, research has overlooked how cognitive performance is affected by the duration and persistence of pain. The current study sought to fill this gap by examining how qualitatively different pain states relate to the following cognitive functions: sustained attention, cognitive control, and psychomotor ability. Patients and methods Patients with musculoskeletal pain in primary care were divided into three pain groups: acute pain (duration <3 months), regularly recurrent pain (duration >3 months), and persistent pain (duration >3 months). These groups were then compared with healthy controls. The MapCog Spectra Test, the Color Word Test, and the Grooved Pegboard Test were used to measure sustained attention, cognitive control, and psychomotor ability, respectively. Results Patients with persistent pain showed significantly worse sustained attention and psychomotor ability compared with healthy controls. The acute pain group showed a significant decrease in psychomotor ability, and the regularly recurrent pain group showed a significant decrease in sustained attention. These results remained unchanged when age, education, and medication were taken into account. Conclusion Persistent musculoskeletal pain seems to impair performance on a wider range of cognitive tasks than acute or regularly recurrent pain, using pain-free individuals as a benchmark. However, there is some evidence of impairment in psychomotor ability among patients with acute pain and some impairment in sustained attention among patients with regularly recurrent pain. Implications Caregivers may need to adjust communication methods when delivering information to cognitively impaired patients. PMID:27799814
Pain behavior mediates the relationship between perceived injustice and opioid prescription for chronic pain: a Collaborative Health Outcomes Information Registry study
Carriere, Junie S; Martel, Marc-Olivier; Kao, Ming-Chih; Sullivan, Michael JL; Darnall, Beth D
Background and purpose Perceived injustice has been defined as an appraisal regarding the severity and irreparability of loss associated with pain, blame and a sense of unfairness. Recent findings have identified perceived injustice as an important risk factor for pain-related outcomes. Studies suggest that perceived injustice is associated with opioid prescription in patients with pain conditions. However, the mechanisms by which perceived injustice is linked to opioid prescription are not well understood. The primary objective of this study was to examine the potential mediating roles of pain intensity, depressive symptoms and pain behavior in the association between perceived injustice and opioid prescription among patients with chronic pain. Methods This cross-sectional study used a sample of 344 patients with chronic pain being treated at a tertiary pain treatment center. Participants completed measures of perceived injustice, pain intensity, depressive symptoms, pain behavior and opioid prescription. Bootstrapped multiple mediation analyses were used to examine the mediating role of patients' pain intensity, depressive symptoms and pain behavior in the association between perceived injustice and opioid prescription. Results Consistent with previous research, we found a significant association between perceived injustice and opioid prescription. Interestingly, results revealed that pain behavior was the only variable that mediated the association between perceived injustice and opioid prescription. Conclusion This study was the first to examine the mechanisms by which perceived injustice is associated with opioid prescription in patients with chronic pain. We found that pain behavior, rather than pain intensity and depressive symptoms, mediated the association between perceived injustice and opioid prescription. Future research in this area should employ a longitudinal research design in order to arrive at clearer causal conclusions about the relationships
The lidocaine metabolite N-ethylglycine has antinociceptive effects in experimental inflammatory and neuropathic pain
Werdehausen, Robert; Mittnacht, Sebastian; Bee, Lucy A.; Minett, Michael S.; Armbruster, Anja; Bauer, Inge; Wood, John N.; Hermanns, Henning; Eulenburg, Volker
Abstract Glycine transporter 1 (GlyT1) plays a crucial role in regulating extracellular glycine concentrations and might thereby constitute a new drug target for the modulation of glycinergic inhibition in pain signaling. Consistent with this view, inhibition of GlyT1 has been found to induce antinociceptive effects in various animal pain models. We have shown previously that the lidocaine metabolite N-ethylglycine (EG) reduces GlyT1-dependent glycine uptake by functioning as an artificial substrate for this transporter. Here, we show that EG is specific for GlyT1 and that in rodent models of inflammatory and neuropathic pain, systemic treatment with EG results in an efficient amelioration of hyperalgesia and allodynia without affecting acute pain. There was no effect on motor coordination or the development of inflammatory edema. No adverse neurological effects were observed after repeated high-dose application of EG. EG concentrations both in blood and spinal fluid correlated with an increase of glycine concentration in spinal fluid. The time courses of the EG and glycine concentrations corresponded well with the antinociceptive effect. Additionally, we found that EG reduced the increase in neuronal firing of wide-dynamic-range neurons caused by inflammatory pain induction. These findings suggest that systemically applied lidocaine exerts antihyperalgesic effects through its metabolite EG in vivo, by enhancing spinal inhibition of pain processing through GlyT1 modulation and subsequent increase of glycine concentrations at glycinergic inhibitory synapses. EG and other substrates of GlyT1, therefore, may be a useful therapeutic agent in chronic pain states involving spinal disinhibition. PMID:25932687
The evaluation of pain in amyotrophic lateral sclerosis: a case controlled observational study.
Wallace, Victoria C J; Ellis, Cathy M; Burman, Rachel; Knights, Catherine; Shaw, Christopher E; Al-Chalabi, Ammar
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder leading to progressive paralysis. ALS is complicated by a number of non-motor symptoms including pain. Pain in ALS has been poorly studied and poorly managed. This study aimed to collate information regarding pain in ALS using standardized pain questionnaires. Forty-two patients with ALS participated in the study. Control subjects included 41 age-matched healthy volunteers and 42 age-matched patients with neurological conditions other than ALS. Data on pain were collected using the The Brief Pain Inventory and The painDetect Questionnaire. Eighty-five percent of subjects with ALS reported pain versus 50% of neurology clinic controls and 35% of healthy controls (p < 0.01). Pain in ALS included cramping, aching, tiring, sharp and tender, and was non-neuropathic. Pain impacted significantly on mood, general activity, relationships and general enjoyment of life. Fifty-four percent of people with painful ALS used regular analgesia and 29% regular opioids. Other non-motor symptoms suffered included tiredness, constipation, urinary problems, itching and drowsiness. In conclusion, these data support the fact that pain is a significant symptom in ALS which impacts on quality of life. These data can be used to educate clinicians and patients to promote better multidisciplinary management of ALS symptoms and a better quality of life.
Pain management for older persons living in nursing homes: a pilot study.
Tse, Mimi M Y; Ho, Suki S K
Because the prevalence of chronic pain among the elderly in nursing homes is high and decreases their quality of life, effective nonpharmacologic pain management should be promoted. The purpose of this quasiexperimental pretest and posttest control design was to enhance pain management in nursing homes via an integrated pain management program (IPMP) for staff and residents. Nursing staff and residents from the experimental nursing home were invited to join the 8-week IPMP, whereas staff and residents from the control nursing home did not receive the IPMP. Baseline data were collected from nursing staff and residents in both groups before and after the IPMP. The IPMP consisted of eight lectures on pain assessment, drug knowledge,and nondrug strategies for the nursing staff, and 8 weeks of activities, including gardening therapy and physiotherapy exercise, for the residents. There were 48 and 42 older people in the experimental and control groups, respectively. No significant differences were found in their educational level, sleep quality, bowel habits, past and present health conditions, pain conditions and psychologic well-being parameters (p > .05) at baseline. After the IPMP, the experimental nursing staff showed a significant improvement in their knowledge of and attitudes to pain management (p < .05), and the experimental residents reported significantly lower pain scores and used more nondrug strategies for pain relief compared with the control group (p < .05). Moreover, the psychologic well-being parameters, including happiness, loneliness, life satisfaction, and geriatric depression, had significantly improved among the experimental residents (p < .05). The IPMP was effective in enhancing the knowledge and attitudes of nursing staff, as well as reducing pain conditions and enhancing psychologic well-being for older persons in nursing homes.
Medial tibial pain: a dynamic contrast-enhanced MRI study.
Mattila, K T; Komu, M E; Dahlström, S; Koskinen, S K; Heikkilä, J
The purpose of this study was to compare the sensitivity of different magnetic resonance imaging (MRI) sequences to depict periosteal edema in patients with medial tibial pain. Additionally, we evaluated the ability of dynamic contrast-enhanced imaging (DCES) to depict possible temporal alterations in muscular perfusion within compartments of the leg. Fifteen patients with medial tibial pain were examined with MRI. T1-, T2-weighted, proton density axial images and dynamic and static phase post-contrast images were compared in ability to depict periosteal edema. STIR was used in seven cases to depict bone marrow edema. Images were analyzed to detect signs of compartment edema. Region-of-interest measurements in compartments were performed during DCES and compared with controls. In detecting periosteal edema, post-contrast T1-weighted images were better than spin echo T2-weighted and proton density images or STIR images, but STIR depicted the bone marrow edema best. DCES best demonstrated the gradually enhancing periostitis. Four subjects with severe periosteal edema had visually detectable pathologic enhancement during DCES in the deep posterior compartment of the leg. Percentage enhancement in the deep posterior compartment of the leg was greater in patients than in controls. The fast enhancement phase in the deep posterior compartment began slightly slower in patients than in controls, but it continued longer. We believe that periosteal edema in bone stress reaction can cause impairment of venous flow in the deep posterior compartment. MRI can depict both these conditions. In patients with medial tibial pain, MR imaging protocol should include axial STIR images (to depict bone pathology) with T1-weighted axial pre and post-contrast images, and dynamic contrast enhanced imaging to show periosteal edema and abnormal contrast enhancement within a compartment.
Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study
Nevitt, Michael C; Niu, Jingbo; Clancy, Mary M; Lane, Nancy E; Link, Thomas M; Vlad, Steven; Tolstykh, Irina; Jungmann, Pia M.; Felson, David T; Guermazi, Ali
Study question Is there concordance between hip pain and radiographic hip osteoarthritis? Methods In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test. Study answer and limitations In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations. What this
Expression of pain among Mi'kmaq children in one Atlantic Canadian community: a qualitative study
Latimer, Margot; Finley, G. Allen; Rudderham, Sharon; Inglis, Stephanie; Francis, Julie; Young, Shelley; Hutt-MacLeod, Daphne
Background First Nation children have the highest rates of pain-related conditions among Canadian children, yet there is little research on how this population expresses its pain or how and whether the pain is successfully treated. The aim of this study was to understand how Mi'kmaq children express pain and how others interpret it. Methods We conducted a qualitative ethnographic study in a large Canadian Mi'kmaq community using interviews and conversation sessions. Participants included children and youth (n = 76), parents (n = 12) teachers (n = 7), elders (n = 6) and health care professionals (n = 13). Results Interpretive descriptive analysis was used and themes regarding pain expression, care seeking and pain management were identified. Pain expression included stoicism and hiding behaviour, and, when pain was discussed, it was via storytelling and descriptive language, such as similes. Participants reported feeling unheard, stereotyped and frustrated when they sought pain care. Frustration led to avoidance of seeking further care, perceptions of racism and repeat visits because of unsuccessful previous treatment. Participants voiced concerns about the utility of the numeric and faces pain scales to describe pain meaningfully. Positive encounters occurred when participants felt respected and heard. Interpretation Mi'kmaq children are stoic and often hide their pain. Community members feel frustrated and discriminated against when their pain is not identified, and conventional pain assessment tools may not be useful. If clinicians consider cultural context, build trust and allow for additional time to assess pain via storytelling or word descriptions as well as a family-centred approach, better pain care may occur. PMID:25114895
Differential Diagnoses for Persistent Pain Following Root Canal Treatment: A Study in the National Dental PBRN
Nixdorf, Donald R.; Law, Alan S.; John, Mike T.; Sobieh, Radwa M.; Kohli, Richie; Nguyen, Ruby H.N.
Introduction Pain present 6 months following root canal treatment (RCT) may be either of odontogenic or nonodontogenic origin. This is importance because treatments and prognoses are different; therefore the aim of this study was to provide specific diagnoses of patients reporting pain 6 months after receiving initial orthograde RCT. Methods We enrolled patients from the Midwest region of an existing prospective observational study of pain after RCT. Pain at 6 months was defined as ≥1 day of pain and average pain intensity of at least 1/10 over the preceding month. An Endodontist and an Orofacial Pain practitioner independently performed clinical evaluations, which included periapical and cone-beam CT radiographs, to determine diagnoses. Results Thirty-eight out of the 354 eligible patients in the geographic area (11%) met the pain criteria, with 19 (50%) consenting to be clinically evaluated. As the sole reason for pain, 7 patients (37%) were given odontogenic diagnoses (4 involving the RCT tooth, 3 involving an adjacent tooth). Eight patients (42%) were given nonodontogenic pain diagnoses (7 from referred temporomandibular disorder (TMD) pain, 1 from persistent dentoalveolar pain disorder (PDAP)). Two patients (11%) had both odontogenic and nonodontogenic diagnoses, while 2 (11%) no longer fit the pain criteria at the time of the clinical evaluation. Conclusion Patients reporting "tooth" pain 6 months following RCT had a nonodontogenic pain diagnosis accounting for some of this pain, with TMD being the most frequent nonodonotgenic diagnosis. Dentists should have the necessary knowledge to differentiate between these diagnoses to adequately manage their patients. PMID:25732400
Self-reports of medication side effects and pain-related activity interference in patients with chronic pain: a longitudinal cohort study.
Martel, Marc O; Finan, Patrick H; Dolman, Andrew J; Subramanian, Subu; Edwards, Robert R; Wasan, Ajay D; Jamison, Robert N
The primary purpose of this study was to examine the association between self-reports of medication side effects and pain-related activity interference in patients with chronic pain. The potential moderators of the association between reports of side effects and pain-related activity interference were also examined. A total of 111 patients with chronic musculoskeletal pain were asked to provide, once a month for a period of 6 months, self-reports of medication use and the presence of any perceived side effects (eg, nausea, dizziness, headaches) associated with their medications. At each of these time points, patients were also asked to provide self-reports of pain intensity, negative affect, and pain-related activity interference. Multilevel modeling analyses revealed that month-to-month increases in perceived medication side effects were associated with heightened pain-related activity interference (P < 0.05). Importantly, multilevel models revealed that perceived medication side effects were associated with heightened pain-related activity interference even after controlling for the influence of patient demographics, pain intensity, and negative affect. This study provides preliminary evidence that reports of medication side effects are associated with heightened pain-related activity interference in patients with chronic pain beyond the influence of other pain-relevant variables. The implications of our findings for clinical practice and the management of patients with chronic pain conditions are discussed.
"An evil heritage": interview study of pain and autosomal dominant polycystic kidney disease.
Heiwe, Susanne; Bjuke, Monica
Pain is a common problem for patients with autosomal dominant polycystic kidney disease (ADPKD). Knowledge about patients' experience of the pain, pain management, and pain's effect on everyday life is, however, limited. In clinical practice there is a need to improve the care of these patients. To be able to do so, information about how the disease and its pain affect the patients is required. This study explores patients' experience of living with ADPKD and its pain. The findings are based on in-depth semistructured interviews. The participants were 22 patients with ADPKD. The data were transcribed and analyzed by using phenomenology. Findings showed that the patients experienced limitations in their everyday life due to inexplicable and unpredictable pain and fatigue. Also, pain management was experienced as suboptimal and pain was seldom discussed at health care appointments. Emotional distress concerning the hereditary nature of the disease was also present. Health care providers need to increase their focus on pain and pain management to reduce the disease's intrusion in patients' everyday life. Also, patients and people in the patients' immediate surroundings need to be given information and education about the disease and its pain as well as the opportunity to talk about their worries concerning heredity. By implementing the findings of the present study when meeting a patient with ADPKD, improved patient satisfaction and health-related quality of life could be accomplished.
Heterogeneous Depression Responses to Chronic Pain Onset among Middle-Aged Adults: A Prospective Study
Zhu, Zhuoying; Galatzer-Levy, Isaac R.; Bonanno, George A.
Studies on depression response to chronic pain are limited by lack of clarification of different forms of response patterns and cross-sectional measures. The current study examined heterogeneous long-term patterns of depression response to chronic pain onset using the mixture modeling technique. Depression symptoms prior to and following pain onset over a course of six years were charted in a nationally representative middle-aged sample. Four distinct depression symptom trajectories emerged. The resilience (72.0%) trajectory describes a pattern of no/minimal depression symptoms prior to and following pain onset. The post-pain depression trajectory (11.4%) describes a pattern of low depression at baseline and increasing symptoms following pain onset. The chronic depression (6.8%) trajectory is characterized by persistently high depression symptoms irrespective of pain onset. The prior depression improved (9.8%) trajectory describes a pattern of high depression at baseline and gradually declining symptoms following pain onset. Self-rated health at both baseline and following pain onset predicted the resilience trajectory. Baseline self-rated health distinguished the post-pain depression and chronic depression trajectories. Individuals in the prior depression improved trajectory were older and had more chronic illnesses at baseline but fewer illnesses following pain onset, compared to those in the resilience or post-pain depression trajectory. PMID:24679514
Pedroni, Cristiane Rodrigues; de Oliveira, Anamaria Siriani; Bérzin, Fausto
Objective: The purpose of the present pilot study was to describe pain complaints of TMD patients and cervical spine dysfunction. Methods: Fourteen women with myogenous TMD, cervical motion limitation and rotation of at least one of the three first cervical vertebrae evidenced by radiographic examination participated in this study. The multidimensional pain evaluation was accomplished by a Brazilian version of the McGill Pain Questionnaire. Results: The results showed that the most painful body site mentioned was cervical spine, followed by scapular region and temporomandibular joint. More than half of the volunteers reported temporal pain pattern as rhythmic, periodic and, or still, intermittent. The majority of the patients classified the pain intensity assessed at the moment of the evaluation as mild to discomforting. Absolute agreement was not observed among volunteers regarding word dimensions used to describe their pain, although a great number of patients chose the descriptor related to tension as the better expression to describe their painful complaint. Conclusion: Pain characteristics of TMD patients with cervical spine dysfunction showed cervical spine as a common painful region reported and words related to affective and emotional dimensions of pain perception can be used by these patients to qualify their pain complain. PMID:19089063
Myofacial pain dysfunction syndrome: a clinical study of asymptomatic subjects.
Cooper, B C; Rabuzzi, D D
The diagnosis of myofacial pain dysfunction (MPD), commonly called temporomandibular joint syndrome, has traditionally been made on the presence of a group of clinical symptoms that produce pain and limitation of movement. The cause of this common illness has been the subject of controversy for over half a century. There has been a lack of agreement on diagnosis, a cause, and treatment. Advanced bioelectronic technology now makes an accurate diagnosis possible, based not merely on clinical symptoms, but on reproducible scientific data. A cause of MPD is discernable and reliable treatment possible, as well as long lasting resolution objectively monitorable with the Mandibular Kinesiograph (MKG 5-R) and Bioelectric Processor (EMIR). A study of mandibular movement and masticular muscle function of 26 "normal" subjects (i.e., clinically asymptomatic) revealed that the overwhelming majority did indeed have dysfunction of the muscles which move and posture the mandible. The significance of this study is twofold. First it demonstrates a valid testing procedure for measuring mandibular movement and muscle function. Second it establishes the fact that most individuals have a physical predisposition to MPD. Changes in the adaptive capacity of the neuromusculature by physical or emotional trauma could then precipitate MPD.
A prospective study of the pathophysiology and clinical characteristics of pain in a palliative medicine population.
Gutgsell, Terence; Walsh, Declan; Zhukovsky, Donna S; Gonzales, Francisco; Lagman, Ruth
Comprehensive pain evaluation is requisite for optimal management. Few studies have evaluated pain syndromes and adequacy of associated analgesic regimens in one population. Available studies in cancer populations have focused on ambulatory patients or hospice-type inpatients. This study was designed to evaluate multiple characteristics of pain and adequacy of therapy in a broad spectrum of patients with advanced cancer presenting to a palliative medicine service. One hundred pain patients (95 with cancer) underwent a comprehensive pain evaluation consisting of history, physical examination, review of available diagnostics, and a pain assessment tool designed for routine clinical use. Seventy-one percent of 141 evaluable patients reported pain in the month before referral. In these 100 patients, 158 distinct sites of pain were reported, with 88 percent reporting a maximum of 2. Pain due to tumor was the most common cause (68 percent), and the most common pathophysiologic mechanism, somatic (52 percent). Pain was almost equally divided between continuous (48 percent) and intermittent (52 percent). Breakthrough pain occurred in 75 percent of continuous pains. Of these, 30 percent were exclusively incidental, 26percent nonincidental, and 16 percent due to end-of-dose failure. The remainder was of mixed etiology, but almost always with an incidental component. Of intermittent pain syndromes, 61 percent were incidental. On referral, analgesic dosing was inadequate and was compounded by use of regimens that typically did not meet peer-reviewed guidelines. Comprehensive studies rigorously evaluating characteristics of pain and response to treatment are a necessary first step toward more effective treatments for difficult pain syndromes.
Frequency, Impact, and Predictors of Persistent Pain Following Root Canal Treatment: A National Dental PBRN Study
Nixdorf, Donald R.; Law, Alan S.; Lindquist, Kimberly; Reams, Gregory J.; Cole, Emery; Kanter, Keith; Nguyen, Ruby H.N.; Harris, D. Robert
Root canal treatment (RCT) is commonly performed surgery and persistent pain is known to occur, but little is known about how these patients are affected by this pain. While biopsychosocial mechanisms are thought to be associated with the development of such pain, similar to persistent pain following surgery in other body sites, little is known about the baseline predictors for persistent pain. We assessed the frequency of persistent pain 6 months following RCT, measured the impact this pain had on patients, and determined predictive factors for persistent tooth pain in a multi-center prospective cohort study conducted within the National Dental Practice-Based Research Network. Of 708 patients enrolled, 651 (91.9%) provided follow-up data, with 65 (10.0%) meeting criteria for pain 6 months following RCT. On average, these patients reported their pain as mild to moderate in intensity, present for about 10 days in the preceding month, and minimally interfered with daily activities. After adjusting for type of dental practitioner and patient age, gender and household income, pain duration over the week prior to RCT significantly increased the risk of developing persistent pain (odds ratio [OR]=1.19 per 1 day increase in pain duration, 95% confidence interval [CI]: 1.07–1.33), whereas optimism about the procedure reduced the risk (OR=0.39, 95% CI: 0.22–0.67). Our data suggest that persistent pain following RCT is fairly common, but generally does not have a large impact on those experiencing it. Furthermore, patient age and gender did not predict persistent pain, while pre-operative pain duration and the patient's expectation did. PMID:26335907
Frequency, impact, and predictors of persistent pain after root canal treatment: a national dental PBRN study.
Nixdorf, Donald R; Law, Alan S; Lindquist, Kimberly; Reams, Gregory J; Cole, Emery; Kanter, Keith; Nguyen, Ruby H N; Harris, D Robert
Root canal treatment (RCT) is commonly performed surgery and persistent pain is known to occur, but little is known about how these patients are affected by this pain. Although biopsychosocial mechanisms are thought to be associated with the development of such pain, similar to persistent pain after surgery in other body sites, little is known about the baseline predictors for persistent pain. We assessed the frequency of persistent pain 6 months after RCT, measured the impact this pain had on patients, and determined predictive factors for persistent tooth pain in a multicenter prospective cohort study conducted within the National Dental Practice-Based Research Network. Of 708 patients enrolled, 651 (91.9%) provided follow-up data, with 65 (10.0%) meeting criteria for pain 6 months after RCT. On average, these patients reported their pain as mild to moderate in intensity, present for approximately 10 days in the preceding month, and minimally interfered with daily activities. After adjusting for the type of dental practitioner and patient age, gender, and household income, pain duration over the week before RCT significantly increased the risk of developing persistent pain (odds ratio = 1.19 per 1 day increase in pain duration, 95% confidence interval: 1.07-1.33), whereas optimism about the procedure reduced the risk (odds ratio = 0.39, 95% confidence interval: 0.22-0.67). Our data suggest that persistent pain 6 months after RCT is fairly common, but generally does not have a large impact on those experiencing it. Furthermore, patient age and gender did not predict persistent pain, whereas preoperative pain duration and the patient's expectation did.
Can Wound Exudate from Venous Leg Ulcers Measure Wound Pain Status?: A Pilot Study
Tamai, Nao; Nakagami, Gojiro; Kitamura, Aya; Naito, Ayumi; Hirokawa, Masayuki; Shimokawa, Chisako; Takahashi, Kazuo; Umemoto, Junichi; Sanada, Hiromi
We investigated the associations between the self-evaluated pain status and two pain biomarker candidates, nerve growth factor and S100A8/A9, in exudate from venous leg ulcer to finally develop an objective pain evaluation method. Patients with venous leg ulcer participated in this cross-sectional observational study conducted between April and October 2014 at two medical facilities. During routine wound care, each participant self-evaluated their pain status at each examination using the 10-point numerical rating scale (present pain intensity) and the short-form McGill Pain Questionnaire 2 (continuous pain, intermittent pain, neuropathic pain, affective descriptors, and total score). Venous leg ulcer exudate sample was collected after wound cleansing. The nerve growth factor and S100A8/A9 concentrations in the venous leg ulcer exudate were measured by enzyme-linked immunosorbent assay and standardized according to the wound area. The association between each pain status and the two standardized protein concentrations was evaluated using Spearman's correlation coefficient. In 30 sample collected from 13 participants, the standardized nerve growth factor concentration was negatively correlated with continuous pain (ρ = -0.47, P = 0.01), intermittent pain (ρ = -0.48, P = 0.01), neuropathic pain (ρ = -0.51, P = 0.01), and total score (ρ = -0.46, P = 0.01). The standardized S100A8/A9 concentration was positively correlated with present pain intensity (ρ = 0.46, P = 0.03) and continuous pain (ρ = 0.48, P = 0.03). Thus, these two proteins may be useful for objective evaluation of wound pain in venous leg ulcer patients. PMID:27936243
A quantitative study of Iranian nursing students' knowledge and attitudes towards pain: implication for education.
Rahimi-Madiseh, Mohammad; Tavakol, Mohsen; Dennick, Reg
It is well documented that pain management and pain assessment is an indispensible part of the nursing care of patients. This study sought to quantify the current knowledge and attitudes of nursing students in Iran about pain management. We conducted a cross-sectional study using a well-validated questionnaire entitled the 'Knowledge and Attitudes Regarding Pain Tool', previously used to evaluate undergraduate nursing students. Results from the survey questionnaire showed that there was a severe deficit in knowledge relating to pain and its management. It is argued that there is a real need for improving the content of pain and its management in the undergraduate nursing education curriculum, which might improve the delivery of optimal nursing care of patients. The limitations of the study are discussed and some recommendations are made for reforming pain management education for future practice.
Multimodal nociceptive mechanisms underlying chronic pelvic pain
HELLMAN, Kevin M.; PATANWALA, Insiyyah Y.; POZOLO, Kristen E.; TU, Frank F.
Objective To evaluate candidate mechanisms underlying the pelvic floor dysfunction in women with chronic pelvic pain and/or painful bladder syndrome/interstitial cystitis. Notably, prior studies have not consistently controlled for potential confounding by psychological or anatomical factors. Study Design As part of a larger study on pelvic floor pain dysfunction and bladder pain sensitivity, we compared a measure of mechanical pain sensitivity, pressure pain thresholds, between women with pelvic pain and pain-free controls. We also assessed a novel pain measure using degree and duration of post-exam pain aftersensation, and conducted structural and functional assessments of the pelvic floor to account for any potential confounding. Phenotypic specificity of pelvic floor measures was assessed with receiver-operator characteristic curves adjusted for prevalence. Results A total of 23 women with chronic pelvic pain, 23 painful bladder syndrome, and 42 pain-free controls completed the study. Women with chronic pelvic pain or painful bladder syndrome exhibited enhanced pain sensitivity with lower pressure pain thresholds (1.18 [interquartile range: 0.87–1.41] kg/cm2) than pain-free participants (1.48 [1.11–1.76] kg/cm2; p<0.001) and prolonged pain aftersensation (3.5 [0–9] vs 0 [0–1] minutes; p< 0.001). Although genital hiatus (p<0.01) was wider in women with chronic pelvic pain there were no consistently observed group differences in pelvic floor anatomy, muscle tone or strength. The combination of pressure pain thresholds and aftersensation duration correlated with severity of pelvic floor tenderness (R2 =41–51, p's< 0.01). Even after adjustment for prevalence, the combined metrics discriminated pain-free controls from women with chronic pelvic pain or painful bladder syndrome (area under the curve=0.87). Conclusion Both experimental assessment of pelvic floor pain thresholds and measurement of sustained pain are independently associated with pelvic pain
The perception of pain in others suppresses somatosensory oscillations: a magnetoencephalography study.
Cheng, Yawei; Yang, Chia-Yen; Lin, Ching-Po; Lee, Po-Lei; Decety, Jean
Accumulating evidence demonstrates that similar neural circuits are activated during the first-hand experience of pain and the observation of pain in others. However, most functional MRI studies did not detect signal change in the primary somatosensory cortex during pain empathy. To test if the perception of pain in others involves the primary somatosensory cortex, neuromagnetic oscillatory activity was recorded from the primary somatosensory cortex in 16 participants while they observed static pictures depicting body parts in painful and non-painful situations. The left median nerve was stimulated at the wrist, and the poststimulus rebounds of the approximately 10-Hz somatosensory cortical oscillations were quantified. Compared to the baseline condition, the level of the approximately 10-Hz oscillations was suppressed during both of the observational situations, indicating the activation of the primary somatosensory cortex. Importantly, watching painful compared to non-painful situations suppressed somatosensory oscillations to a significant stronger degree. In addition, the suppression caused by perceiving others in the painful relative to the non-painful situations correlated with the perspective taking subscale of the interpersonal reaction index. These results, consistent with the mirror-neuron system, demonstrate that the perception of pain in others modulates neural activity in primary somatosensory cortex and supports the idea that the perception of pain in others elicits subtle somatosensory activity that may be difficult to detect by fMRI techniques.
Sleep problems and pain: a longitudinal cohort study in emerging adults.
Bonvanie, Irma J; Oldehinkel, Albertine J; Rosmalen, Judith G M; Janssens, Karin A M
Sleep and pain are thought to be bidirectional related on a daily basis in adolescents with chronic pain complaints. In addition, sleep problems have been shown to predict the long-term onset of musculoskeletal pain in middle-aged adults. Yet, the long-term effects of sleep problems on pain duration and different types of pain severity in emerging adults (age: 18-25) are unknown. This study investigated the cross-sectional and longitudinal relationship between sleep problems and chronic pain, and musculoskeletal pain, headache, and abdominal pain severity in a general population of emerging adults. We studied whether these relationships were moderated by sex and whether symptoms of anxiety and depression, fatigue, or physical inactivity mediated these effects. Data of participants from the longitudinal Dutch TRacking Adolescents' Individual Lives Survey were used. Follow-up data were collected in 1753 participants who participated in the fourth (N = 1668, mean age: 19.0 years [SD = 0.6]) and/or fifth (N = 1501, mean age: 22.3 years [SD = 0.6]) assessment wave. Autoregressive cross-lagged models were used for analyses. Sleep problems were associated with chronic pain, musculoskeletal pain, headache and abdominal pain severity, and predicted chronic pain and an increase in musculoskeletal pain severity at 3 years of follow-up. This prospective effect was stronger in females than in males and was mediated by fatigue but not by symptoms of anxiety and depression or physical inactivity. Only abdominal pain had a small long-term effect on sleep problems. Our results suggest that sleep problems may be an additional target for treatment in female emerging adults with musculoskeletal pain complaints.
An Exploratory Study into Objective and Reported Characteristics of Neuropathic Pain in Women with Chronic Pelvic Pain
Whitaker, Lucy H. R.; Reid, Jen; Choa, Alex; McFee, Stuart; Seretny, Marta; Wilson, John; Elton, Rob A.; Vincent, Katy; Horne, Andrew W.
Chronic pelvic pain (CPP) affects 5.7–26.6% women worldwide. 55% have no obvious pathology and 40% have associated endometriosis. Neuropathic pain (NeP) is pain arising as a consequence of a lesion/disease affecting the somatosensory system. The prevalence of NeP in women with CPP is not known. The diagnosis of NeP is challenging because there is no gold-standard assessment. Questionnaires have been used in the clinical setting to diagnose NeP in other chronic pain conditions and quantitative sensory testing (QST) has been used in a research setting to identify abnormal sensory function. We aimed to determine if women with chronic pelvic pain (CPP) have a neuropathic pain (NeP) component to their painful symptoms and how this is best assessed. We performed an exploratory prospective cohort study of 72 pre-menopausal women with a diagnosis of CPP. They underwent a clinician completed questionnaire (DN4) and completed the S-LANSS and PainDETECT™ questionnaires. Additionally QST testing was performed by a clinician. They also completed a patient acceptability questionnaire. Clinical features of NeP were identified by both questionnaires and QST. Of the women who were NeP positive, 56%, 35% and 26% were identified by the S-LANSS, DN4 and PainDETECT™ respectively. When NeP was identified by questionnaire, the associated laparoscopy findings were similar irrespective of which questionnaire was used. No subject had entirely unchanged QST parameters. There were distinct loss and gain subgroups, as well as mixed alteration in function, but this was not necessarily clinically significant in all patients. 80% of patients were confident that questionnaires could diagnose NeP, and 90% found them easy to complete. Early identification of NeP in women with CPP with a simple questionnaire could facilitate targeted therapy with neuromodulators, which are cheap, readily available, and have good safety profiles. This approach could prevent unnecessary or fertility
Combined neuromodulatory interventions in acute experimental pain: assessment of melatonin and non-invasive brain stimulation
da Silva, Nádia Regina Jardim; Laste, Gabriela; Deitos, Alícia; Stefani, Luciana Cadore; Cambraia-Canto, Gustavo; Torres, Iraci L. S.; Brunoni, Andre R.; Fregni, Felipe; Caumo, Wolnei
Transcranial direct current stimulation (tDCS) and melatonin can effectively treat pain. Given their potentially complementary mechanisms of action, their combination could have a synergistic effect. Thus, we tested the hypothesis that compared to the control condition and melatonin alone, tDCS combined with melatonin would have a greater effect on pain modulatory effect, as assessed by quantitative sensory testing (QST) and by the pain level during the Conditioned Pain Modulation (CPM)-task. Furthermore, the combined treatment would have a greater cortical excitability effect as indicated by the transcranial magnetic stimulation (TMS) and on the serum BDNF level. Healthy males (n = 20), (aged 18–40 years), in a blinded, placebo-controlled, crossover, clinical trial, were randomized into three groups: sublingual melatonin (0.25 mg/kg) + a-tDCS, melatonin (0.25 mg/kg) + sham-(s)-tDCS, or sublingual placebo+sham-(s)-tDCS. Anodal stimulation (2 mA, 20 min) was applied over the primary motor cortex. There was a significant difference in the heat pain threshold (°C) for melatonin+a-tDCS vs. placebo+s-tDCS (mean difference: 4.86, 95% confidence interval [CI]: 0.9 to 8.63) and melatonin+s-tDCS vs. placebo+s-tDCS (mean: 5.16, 95% CI: 0.84 to 8.36). There was no difference between melatonin+s-tDCS and melatonin+a-tDCS (mean difference: 0.29, 95% CI: −3.72 to 4.23). The mean change from the baseline on amplitude of motor evocate potential (MEP) was significantly higher in the melatonin+a-tDCS (−19.96% ± 5.2) compared with melatonin+s-tDCS group (−1.36% ± 5.35) and with placebo+s-tDCS group (3.61% ± 10.48), respectively (p < 0.05 for both comparisons). While melatonin alone or combined with a-tDCS did not significantly affect CPM task result, and serum BDNF level. The melatonin effectively reduced pain; however, its association with a-tDCS did not present an additional modulatory effect on acute induced pain. PMID:25873871
"I feel your pain": a research study addressing perianesthesia health care providers' knowledge and attitudes toward pain.
Burns, Julie; Magee, Kerstin T; Cooley, Hayley; Hensler, Anne; Montana, Joanne; Shumaker, Daria; Snyder, Jane; Polk, Artisha R
Patients' feedback about their perianesthesia experience at an acute care 609-bed teaching hospital in Washington, DC, indicated that pain management was an area in need of improvement. A nonexperimental descriptive study related to pain management was conducted in the perianesthesia areas to assess the knowledge and attitudes of health care providers. McCaffrey and Ferrell's 38-item self-report questionnaire was given to anesthesia providers, preoperative nurses, Phase I nurses, and Phase II nurses (N=138). Seventy-two participants responded, yielding a 52% response rate. Results showed a statistically significant difference between the scores of the anesthesia care providers and the preoperative area nurses and between the Phase I nurses and the preoperative nurses. No statistically significant differences were found between the anesthesia providers, and Phase I and Phase II nurses, indicating that at this hospital, nurses who provide postoperative care have similar knowledge and attitudes regarding pain as the anesthesia providers.
Relationship between self-reported pain sensitivity and pain after total knee arthroplasty: a prospective study of 71 patients 8 weeks after a standardized fast-track program
Valeberg, Berit T; Høvik, Lise H; Gjeilo, Kari H
Background and purpose This was a prospective cohort study assessing data from 71 adult patients undergoing total knee arthroplasty (TKA) following a standardized fast-track program between January and July 2013. The objective was to examine the relationship between self-rated pain sensitivity, as measured by the Pain Sensitivity Questionnaire (PSQ), and postoperative pain after TKA. Methods The baseline questionnaires, PSQ and Brief Pain Inventory, were given to the patients for self-administration at the presurgical evaluation (1–2 weeks prior to surgery). The follow-up questionnaire, Brief Pain Inventory, was administered at the first follow-up, 8 weeks after surgery. Results A statistically significant association was found between average preoperative pain and average pain 8 weeks after surgery (P=0.001). The PSQ-minor was statistically significantly associated with average pain only for patients younger than 70 years (P=0.03). Interpretation This is the first study to examine the relationship between pain sensitivity measured by PSQ and postoperative pain in patients after TKA. We found that a lower score on the PSQ-minor was statistically significantly associated with patients' pain 8 weeks after TKA surgery, but only for younger patients. Further research is needed to explore whether the PSQ could be a useful screening tool for patients' pain sensitivity in clinical settings. PMID:27660489
Neuropathic pain may be common in chronic lower limb tendinopathy: a prospective cohort study
Wheeler, Patrick C
Background: To identify the prevalence of neuropathic pain, through the use of the painDETECT questionnaire, in a cohort of patients with chronic lower limb tendinopathy conditions. Methods: Patients with chronic lower limb tendinopathy conditions treated within a Sport and Exercise Medicine hospital clinic were identified from clinical records. At the time of the clinical consultation, pain and painDETECT scores were recorded. Results: In total, 282 suitable patients with chronic lower limb tendinopathy conditions were identified who had completed a painDETECT questionnaire. There was a median age of 51.9 years, 35% of patients were male and a median duration of symptoms of 24.0 months. There was a median score of 7.0/10 for self-reported 'average' pain and 8.0/10 for self-reported 'worst' pain. There was a median painDETECT score of 14.0, 28% of respondents scored 19 or higher with painDETECT (neuropathic component to pain may be likely), 29% scored 13–18 (equivocal result) and 43% of respondents scored 12 or less (neuropathic pain component was unlikely). Conclusions: This study suggests that neuropathic pain as identified by the painDETECT questionnaire may be common in patients with chronic lower limb tendinopathy conditions. It is unclear if patients with tendinopathy who have neuropathic pain may have poorer outcomes from initial treatments, contributing to the high proportion seen in secondary care. These are results from a single hospital clinic, and comparison with a control group is currently lacking. However, on the results to date, neuropathic pain should be considered in management strategies in patients with chronic tendinopathy. PMID:28386400
Experimental study and evaluation of radioprotective drugs
NASA Technical Reports Server (NTRS)
Smith, D. E.; Thomson, J. F.
Experimental study evaluates radioprotective drugs administered before exposure either orally or intravenously. Specifically studied are the sources of radiation, choice of radiation dose, choice of animals, administration of drugs, the toxicity of protective agents and types of protective drug.
The effect of local vs remote experimental pain on motor learning and sensorimotor integration using a complex typing task.
Dancey, Erin; Murphy, Bernadette A; Andrew, Danielle; Yielder, Paul
Recent work demonstrated that capsaicin-induced acute pain improved motor learning performance; however, baseline accuracy was very high, making it impossible to discern the impact of acute pain on motor learning and retention. In addition, the effects of the spatial location of capsaicin application were not explored. Two experiments were conducted to determine the interactive effects of acute pain vs control (experiment 1) and local vs remote acute pain (experiment 2) on motor learning and sensorimotor processing. For both experiments, somatosensory evoked potential (SEP) amplitudes and motor learning acquisition and retention (accuracy and response time) data were collected at baseline, after application, and after motor learning. Experiment 1: N11 (P < 0.05), N13 (P < 0.05), and N30 (P < 0.05) SEP peak amplitudes increased after motor learning in both groups, whereas the N20 SEP peak increased in the control group (P < 0.05). At baseline, the intervention group outperformed the control group in accuracy (P < 0.001). Response time improved after motor learning (P < 0.001) and at retention (P < 0.001). Experiment 2: The P25 SEP peak decreased in the local group after application of capsaicin cream (P < 0.01), whereas the N30 SEP peaks increased after motor learning in both groups (P < 0.05). Accuracy improved in the local group at retention (P < 0.005), and response time improved after motor learning (P < 0.005) and at retention (P < 0.001). This study suggests that acute pain may increase focal attention to the body part used in motor learning, contributing to our understanding of how the location of pain impacts somatosensory processing and the associated motor learning.
Chronic pain relief after the exposure of nitrous oxide during dental treatment: longitudinal retrospective study.
Mattos Júnior, Francisco Moreira; Mattos, Rafael Villanova; Teixeira, Manoel Jacobsen; Siqueira, Silvia Regina Dowgan Tesseroli de; Siqueira, Jose Tadeu Tesseroli de
The objective was to investigate the effect of nitrous/oxygen in chronic pain. Seventy-seven chronic pain patients referred to dental treatment with conscious sedation with nitrous oxide/oxygen had their records included in this research. Data were collected regarding the location and intensity of pain by the visual analogue scale before and after the treatment. Statistical analysis was performed comparing pre- and post-treatment findings. It was observed a remarkable decrease in the prevalence of pain in this sample (only 18 patients still had chronic pain, p < 0.001) and in its intensity (p < 0.001). Patients that needed fewer sessions received higher proportions of nitrous oxide/oxygen. Nitrous oxide may be a tool to be used in the treatment of chronic pain, and future prospective studies are necessary to understand the underlying mechanisms and the effect of nitrous oxide/oxygen in patients according to the pain diagnosis and other characteristics.
Pattern and quality of care of cancer pain management. Results from the Cancer Pain Outcome Research Study Group.
Apolone, G; Corli, O; Caraceni, A; Negri, E; Deandrea, S; Montanari, M; Greco, M T
Most patients with advanced or metastatic cancer experience pain and despite several guidelines, undertreatment is well documented. A multicenter, open-label, prospective, non-randomised study was launched in Italy in 2006 to evaluate the epidemiology, patterns and quality of pain care of cancer patients. To assess the adequacy of analgesic care, we used a standardised measure, the pain management index (PMI), that compares the most potent analgesic prescribed for a patient with the reported level of the worst pain of that patient together with a selected list of clinical indicators. A total of 110 centres recruited 1801 valid cases. 61% of cases were received a WHO-level III opioid; 25.3% were classified as potentially undertreated, with wide variation (9.8-55.3%) according to the variables describing patients, centres and pattern of care. After adjustment with a multivariable logistic regression model, type of recruiting centre, receiving adjuvant therapy or not and type of patient recruited (new or already on follow-up) had a significant association with undertreatment. Non-compliance with the predefined set of clinical indicators was generally high, ranging from 41 to 76%. Despite intrinsic limitations of the PMI that may be considered as an indicator of the poor quality of cancer pain care, results suggest that the recourse to WHO third-level drugs still seems delayed in a substantial percentage of patients. This delay is probably related to several factors affecting practice in participating centres and suggests that the quality of cancer pain management in Italy deserves specific attention and interventions aimed at improving patients' outcomes.
Pattern and quality of care of cancer pain management. Results from the Cancer Pain Outcome Research Study Group
Apolone, G; Corli, O; Caraceni, A; Negri, E; Deandrea, S; Montanari, M; Greco, M T
Most patients with advanced or metastatic cancer experience pain and despite several guidelines, undertreatment is well documented. A multicenter, open-label, prospective, non-randomised study was launched in Italy in 2006 to evaluate the epidemiology, patterns and quality of pain care of cancer patients. To assess the adequacy of analgesic care, we used a standardised measure, the pain management index (PMI), that compares the most potent analgesic prescribed for a patient with the reported level of the worst pain of that patient together with a selected list of clinical indicators. A total of 110 centres recruited 1801 valid cases. 61% of cases were received a WHO-level III opioid; 25.3% were classified as potentially undertreated, with wide variation (9.8–55.3%) according to the variables describing patients, centres and pattern of care. After adjustment with a multivariable logistic regression model, type of recruiting centre, receiving adjuvant therapy or not and type of patient recruited (new or already on follow-up) had a significant association with undertreatment. Non-compliance with the predefined set of clinical indicators was generally high, ranging from 41 to 76%. Despite intrinsic limitations of the PMI that may be considered as an indicator of the poor quality of cancer pain care, results suggest that the recourse to WHO third-level drugs still seems delayed in a substantial percentage of patients. This delay is probably related to several factors affecting practice in participating centres and suggests that the quality of cancer pain management in Italy deserves specific attention and interventions aimed at improving patients' outcomes. PMID:19401688
Characteristics of Patients with Lower Extremity Trauma with Improved and Not Improved Pain During Hospitalization: A pilot study
Griffioen, Mari A; Johantgen, Meg; Von Rueden, Kathryn; Greenspan, Joel D.; Dorsey, Susan G.; Renn, Cynthia L.
Background Up to 62% of patients report chronic pain at the injury site 6-12 months after blunt trauma, with pain from lower extremity fractures exceeding that from other sites. High pain intensity at time of injury is a risk factor for chronic pain, but it is not clear what patient characteristics influence the pain intensity level during the immediate hospitalization following injury. Aim The purpose of this pilot study was to determine the feasibility of collecting pain scores from medical records, to calculate pain trajectories, and to determine whether it is possible to examine patient characteristics by classifying them into those whose pain improved and those whose pain did not improve. Design This descriptive study retrospectively reviewed medical records of 18 randomly chosen patients admitted to an academic trauma center. Methods Patient characteristics and pain scores were collected form electronic and handwritten medical records. Results The pain trajectories calculated from routinely collected pain scores during the in-patient stay showed that for 44% of the patients the pain improved during the hospitalization, for 39% the pain remained the same and for 17% the pain worsened. Variables age, smoking, weight, abbreviated injury scores, length of hospital stay, mean pain score and opioid equianalgesic dose differed based on pain trajectory. Conclusion While patient characteristics differed based on pain trajectory, any significant effects seen from individual tests should be considered tentative, given the number of analyses conducted on this data set. However, feasibility and significance of conducting a larger study has been established. PMID:26545732
Effects of position change on lumbar pain and discomfort of Korean patients after invasive percutaneous coronary intervention: a RCT study
Cha, Nam Hyun; Sok, Sohyune
[Purpose] This study sought to examine the effects of position change on lumbar pain and discomfort of Korean patients after invasive percutaneous coronary intervention. [Subjects and Methods] The participants consisted of 48 patients (experimental: n=24, control: n=24) who underwent invasive coronary intervention (Percutaneous Coronary Intervention) in K hospital, Seoul, Korea. A randomized controlled trial design was used. Position changes as the experimental treatment were sequenced as follows: supine position for one hour after removal of the catheter; 30-degree bed-elevated lateral position for one hour; 30-degree bed elevation for one hour; and finally 30-degree bed-elevated lateral position for one hour. The thirty degree bed-elevated lateral position was intended to press on the surgical site. Measures used were the general characteristics form, Visual Analogue Scale for lumbar pain, and discomfort scale. [Results] There were significant differences on lumbar pain and discomfort of Korean patients after invasive coronary intervention between the experimental and control groups. [Conclusion] Position change was an effective intervention for decreasing lumbar pain and discomfort of Korean patients after invasive coronary intervention. Health professionals need to consider an array of methods including position change for patients after invasive coronary intervention. PMID:27821926
Neural Correlates of Empathy with Pain Show Habituation Effects. An fMRI Study
Preis, Mira A.; Kröner-Herwig, Birgit; Schmidt-Samoa, Carsten; Dechent, Peter; Barke, Antonia
Background Neuroimaging studies have demonstrated that the actual experience of pain and the perception of another person in pain share common neural substrates, including the bilateral anterior insular cortex and the anterior midcingulate cortex. As many fMRI studies include the exposure of participants to repeated, similar stimuli, we examined whether empathic neural responses were affected by habituation and whether the participants' prior pain experience influenced these habituation effects. Method In 128 trials (four runs), 62 participants (31 women, 23.0 ± 4.2 years) were shown pictures of hands exposed to painful pressure (pain pictures) and unexposed (neutral pictures). After each trial, the participants rated the pain of the model. Prior to the experiment, participants were either exposed to the same pain stimulus (pain exposure group) or not (touch exposure group). In order to assess possible habituation effects, linear changes in the strength of the BOLD response to the pain pictures (relative to the neutral pictures) and in the ratings of the model's pain were evaluated across the four runs. Results Although the ratings of the model's pain remained constant over time, we found neural habituation in the bilateral anterior/midinsular cortex, the posterior midcingulate extending to dorsal posterior cingulate cortex, the supplementary motor area, the cerebellum, the right inferior parietal lobule, and the left superior frontal gyrus, stretching to the pregenual anterior cingulate cortex. The participant's prior pain experience did neither affect their ratings of the model's pain nor their maintenance of BOLD activity in areas associated with empathy. Interestingly, participants with high trait personal distress and fantasy tended to show less habituation in the anterior insula. Conclusion Neural structures showed a decrease of the BOLD signal, indicating habituation over the course of 45 minutes. This can be interpreted as a neuronal mechanism
A Prospective Multicentre Study to Improve Postoperative Pain: Identification of Potentialities and Problems
Pogatzki-Zahn, Esther; Kutschar, Patrick; Nestler, Nadja; Osterbrink, Juergen
Many studies still indicate insufficient pain management after surgery, e.g., in patients after small- or medium-size operations. Yet it is still uncertain if postoperative pain based on patient-related outcomes can be improved by implementing guideline-related programmes in a multicentre approach. Adult patients in six hospitals in one German city were included in this prospective study. Data collection took place twice in each hospital, once before and once after implementation of concepts and in-house training. Pain and pain-related aspects were assessed one day after surgery and compared between the pre- and post-test group including subgroup analysis of certain surgical procedures by using Student's t-tests, Mann-Whitney U tests and chi-square tests (alphatwo-tailed = 0.05). Overall, pain at rest and during movement was slightly lower after the intervention. Significant changes were observed after thoracic surgery, small joint surgery and other minor surgical procedures. The rather moderate decrease in pain likely relates to a reasonable pre-existing pain management and to detached improvements in certain patient subgroups. Interestingly, specific analyses revealed significantly lower post-test pain as compared to pre-test pain only in patients without pre-existing chronic pain. Side effects related to pain medication were significantly lower after intervention. Our data show, for the first time, benefits of a perioperative teaching programme in a multicentre approach. Pain ratings improved mainly in specific subgroups of patients, e.g., small surgical procedures and patients without preoperative pain. Thus, general improvement is possible but special attention should be paid to the group of patients with preoperative pain. PMID:26600464
Thomas Paine's "Common Sense": A Study in Polarity.
ERIC Educational Resources Information Center
Blair, Carole
Thomas Paine's "Common Sense," published in 1776, was a significant rhetorical event, having a polarizing effect on a situation marked by confusion and conflicting loyalties, in which prevailing views favored reconciliation of the American colonies with England. Paine's rhetoric intensified the conflict, forcing a cognitive restructuring…
The relationship between expectation, experience and perception of labour pain: an observational study.
Aksoy, Huseyin; Yücel, Burak; Aksoy, Ulku; Acmaz, Gokhan; Aydin, Turgut; Babayigit, Mustafa Alparslan
The present study was aimed to assess the relationship between pain expectation before labour, labour pain and pain perception after the labour. Pregnant women were asked to rate their pain level on a standard continuous visual analogue scale at various time points. Pain expectancy (PE), labour pain (LP) and postpartum pain perception (PPP) scores were calculated. The final study group was composed of 230 pregnant women after exclusions. Mean age of pregnant women was 26.2 ± 5.79. The mean PE, LP, and PPP scores were 70.11 ± 18.82, 75.72 ± 19.2 and 65.84 ± 19.56, respectively. The difference among pain scores was statistically significant (p < 0.001). There was a positive correlation between PE and LP or PE and PPP scores (p = 0.27 and p = 0.21). The correlations were statistically significant (p = 0.01 or p = 0.01). In addition, there was a positive correlation between LP and PPP scores (p = 0.87) and the correlation was statistically significant (p = 0.01). This study showed that, if pregnant women had lower expectations of pain before the labour, they indeed experienced lower amount of pain during the labour.
Dynamic Compression Enhances Pressure-to-Pain Threshold in Elite Athlete Recovery: Exploratory Study.
Sands, William A; McNeal, Jeni R; Murray, Steven R; Stone, Michael H
Athlete recovery-adaptation is crucial to the progress and performance of highly trained athletes. The purpose of this study was to assess peristaltic pulse dynamic compression (PPDC) in reducing short-term pressure-to-pain threshold (PPT) among Olympic Training Center athletes after morning training. Muscular tenderness and stiffness are common symptoms of fatigue and exercise-induced muscle microtrauma and edema. Twenty-four highly trained athletes (men = 12 and women = 12) volunteered to participate in this study. The athletes were randomly assigned to experimental (n = 12) and control (n = 12) groups. Pressure-to-pain threshold measurements were conducted with a manual algometer on 3 lower extremity muscles. Experimental group athletes underwent PPDC on both legs through computer-controlled circumferential inflated leggings that used a peristaltic-like pressure pattern from feet to groin. Pressures in each cell were set to factory defaults. Treatment time was 15 minutes. The control group performed the same procedures except that the inflation pump to the leggings was off. The experimental timeline included a morning training session, followed by a PPT pretest, treatment application (PPDC or control), an immediate post-test (PPT), and a delayed post-test (PPT) after the afternoon practice session. Difference score results showed that the experimental group's PPT threshold improved after PPDC treatment immediately and persisted the remainder of the day after afternoon practice. The control group showed no statistical change. We conclude that PPDC is a promising means of accelerating and enhancing recovery after the normal aggressive training that occurs in Olympic and aspiring Olympic athletes.
Effects of context and individual predispositions on hypervigilance to pain-cues: an ERP study
Dittmar, Oliver; Baum, Corinna; Schneider, Raphaela; Lautenbacher, Stefan
Background Hypervigilance to pain is the automatic prioritization of pain-related compared with other stimuli. The processing of threat information is influenced by negative contexts. Therefore, we intended to explore such context effects on hypervigilance to pain-cues, taking individual differences in self-reported vigilance to pain into consideration. Methods In all, 110 healthy subjects viewed task-irrelevant emotional facial expressions (anger, happy, neutral, and pain) overlaid in half of the trials with a fine grid. The instructed task was to indicate the presence/absence of this grid. A threatening context was established by applying electrical stimuli slightly below pain-threshold. Using scores of Pain Vigilance and Awareness Questionnaire, the sample was divided into high vs low pain vigilant subjects. Reaction times and event-related brain potentials were recorded. Results No distinct attentional processing of pain faces (based on the event-related brain potentials) was observed as a function of high levels of self-reported vigilance to pain and contextual threat induction. High pain vigilant subjects showed generally enhanced processing of emotional and neutral faces as indicated by parameters of early (early posterior negativity) and late (late positive complex) processing stages. This enhancement was abolished when electro-stimuli were presented. Conclusion Contextual threat does not enhance the attentional capture of pain-cues when they are presented concurrently with competing task demands. The study could, however, replicate a generally enhanced attentional processing of emotional cues in high pain vigilant subjects. This underpins that hypervigilance to pain is related to changes in emotional processing. PMID:26316802
Teachers' experiences of adolescents' pain in everyday life: a qualitative study
Rohde, Gudrun; Westergren, Thomas; Haraldstad, Kristin; Johannessen, Berit; Høie, Magnhild; Helseth, Sølvi; Fegran, Liv; Slettebø, Åshild
Objectives More adolescents report pain now than previously. In Norway, episodic pain problems have been reported by 60% of children and adolescents aged 8–18 years, with 21% reporting duration of pain of more than 3 months. Since adolescents spend much time at school, the attitude and behaviour of teachers play important roles regarding the experience of pain felt by adolescents in everyday life. Yet research on how teachers perceive the pain experienced by adolescents in a school setting is limited. We therefore seek to gain insight to teachers' classroom experiences with (1) adolescent's self-reported pain symptoms; (2) adolescents management of their pain and (3) how to help adolescents manage their pain. Setting Teachers in 5 junior high schools in Norway representing municipalities in 3 rural areas and 2 cities. Research design A qualitative study with an explorative design comprising 5 focus group interviews. Each group consisted of 3–8 junior high school teachers. A semistructured interview guide was used to cover the issues. The transcribed text was analysed with qualitative content analysis. Participants 22 teachers participated (5 men, 17 women; age range 29–62 years) with teaching experience ranging from 3 to nearly 40 years. Results The main theme describing the experience of teachers with adolescents' pain in everyday life is that pain and management of pain is a social, physical and psychological interwoven phenomenon. Through empirical analyses, 3 subcategories emerged: (1) everyday pain—expressing strenuous life; (2) managing pain—escaping struggle and (3) strategies of teachers—support and normalisation. Conclusions Teachers have a biopsychosocial understanding and approach to pain experienced by adolescents. This understanding influences the role of teachers as significant others in the lives of adolescents with regard to pain and management of their pain in a school setting. PMID:26338838
A burden of illness study for neuropathic pain in Europe
Liedgens, Hiltrud; Obradovic, Marko; De Courcy, Jonathan; Holbrook, Timothy; Jakubanis, Rafal
Purpose Neuropathic pain (NP) is often severe and represents a major humanistic and economic burden. This study aimed at providing insight on this burden across France, Germany, Italy, Spain, and the UK, considering direct and indirect costs, productivity loss, and humanistic impact on patients and their families. Methods Physician questionnaires provided data on patients presenting with NP covering demographics, sick leave and retirement, number of consultations, drug treatments, and surgical procedures. Patients provided further demographic and disease-related data and completed the Work Productivity and Activity Impairment (WPAI), the EuroQol 5-Dimension (EQ-5D), and the Brief Pain Inventory (BPI) questionnaires. All health-related direct unitary costs were collected from relevant country-specific sources and adjusted to 2012 prices (€) where necessary. A subgroup analysis of costs based on diabetic peripheral neuropathy (n=894), fibromyalgia (n=300), and low back pain (n=963) was performed. Findings About 413 physicians completed a total of 3,956 patient records forms. Total annual direct health-care costs per patient ranged from €1,939 (Italy) to €3,131 (Spain). Annual professional caregiver costs ranged from €393 (France) to €1,242 (UK), but this only represented a small proportion of total care because much care is provided by family or friends. Sick leave costs ranged from €5,492 (UK) to €7,098 (France), with 10%–32% patients prevented from working at some point by NP. Total cost (including direct and indirect costs) of NP per patient was €10,313 in France (69% of the total cost), €14,446 in Germany (78%), €9,305 in Italy (69%), €10,597 in Spain (67%), and €9,685 in the UK (57%). Indirect costs (ie, sick leave) constituted the majority of costs in all five countries: €7,098 in France, €11,232 in Germany, €6,382 in Italy, €7,066 in Spain, and €5,492 in the UK. In the subgroup analysis, total annual direct costs per patient
Therapeutic Education in Improving Cancer Pain Management: A Synthesis of Available Studies.
Prevost, Virginie; Delorme, Claire; Grach, Marie-Christine; Chvetzoff, Gisèle; Hureau, Magalie
This literature review aims to synthesize available studies and to update findings in order to obtain a current, comprehensive estimate of the benefits of pain education. Forty-four original articles obtained from the PubMed database were analyzed to investigate which protocols could be most effective in improving pain management. Recent studies indicate a growing interest in evaluating patients' skills and attitudes; these include satisfaction with cancer pain treatment, patient-reported improvement, and patient participation-all of which could be dependable benchmarks for evaluating the effectiveness of educational programs. Besides pain measurement, recent studies advance support for the importance of assessing newly developed outcome criteria. In this sense, patients' active participation and decision making in their pain management are probably the most relevant goals of pain education.
Pain-Related Brain Activity Evoked by Active and Dynamic Arm Movement: Delayed-Onset Muscle Soreness as a Promising Model for Studying Movement-Related Pain in Humans
Matsuda, Yoichi; Kan, Shigeyuki; Uematsu, Hironobu; Shibata, Masahiko; Fujino, Yuji
Objective To demonstrate delayed-onset muscle soreness (DOMS) is a suitable model for the study of movement-evoked pain, we attempted to identify brain regions specifically involved in pain evoked by active and dynamic movement under DOMS condition. Subject Twelve healthy volunteers Methods DOMS was induced in the left upper-arm flexor muscles by an eccentric elbow contraction exercise. Movement-evoked pain in the affected muscles was evaluated just before (day 0) and after (days 1–7 and 30) the exercise using a visual analog scale. Subjects underwent functional magnetic resonance imaging scans while performing repeated elbow flexion on day 2 (DOMS condition) and day 30 (painless condition). We compared brain activity between the DOMS and painless conditions. Results Movement-evoked pain reached peak intensity on day 2 and disappeared by day 30 in all subjects. No subject felt pain at rest on either of these days. Contralateral primary motor cortex (M1), parietal operculum and bilateral presupplementary motor area (pre-SMA) showed greater activity during active and dynamic arm movement with DOMS than during the same movement without pain. There was no difference in activation of brain regions known collectively as the "pain matrix," except for the parietal operculum, between the two conditions. Conclusion Active and dynamic movement with pain selectively evoked activation of M1, pre-SMA, and parietal operculum, as assessed using DOMS. Our results demonstrate that DOMS is a promising experimental model for the study of movement-evoked pain in humans. PMID:25929675
Partner-guided cancer pain management at the end of life: a preliminary study.
Keefe, Francis J; Ahles, Tim A; Sutton, Linda; Dalton, JoAnn; Baucom, Don; Pope, Mary Susan; Knowles, Verena; McKinstry, Elizabeth; Furstenberg, Charlotte; Syrjala, Karen; Waters, Sandra J; McKee, Daphne; McBride, Colleen; Rumble, Meredith; Scipio, Cindy
This preliminary study tested the efficacy of a partner-guided cancer pain management protocol for patients who are at the end of life. Seventy-eight advanced cancer patients meeting criteria for hospice eligibility and their partners were randomly assigned to a partner-guided pain management training intervention, or usual care control condition. The partner-guided pain management training protocol was a three-session intervention conducted in patients' homes that integrated educational information about cancer pain with systematic training of patients and partners in cognitive and behavioral pain coping skills. Data analyses revealed that the partner-guided pain management protocol produced significant increases in partners' ratings of their self-efficacy for helping the patient control pain and self-efficacy for controlling other symptoms. Partners receiving this training also showed a trend to report improvements in their levels of caregiver strain. Overall, the results of this preliminary study suggest that a partner-guided pain management protocol may have benefits in the context of cancer pain at the end of life. Given the significance of pain at the end of life, future research in this area appears warranted.
Persistent pain after total knee or hip arthroplasty: differential study of prevalence, nature, and impact
Pinto, Patrícia R; McIntyre, Teresa; Ferrero, Ramón; Araújo-Soares, Vera; Almeida, Armando
This study compares the incidence, nature, and impact of persistent post-surgical pain after total knee arthroplasty (TKA) and total hip arthroplasty (THA) and investigates differences between these procedures, with the focus on potential presurgical and post-surgical issues that could be related to the distinct persistent post-surgical pain outcomes between these two groups. A consecutive sample of 92 patients was assessed prospectively 24 hours before, 48 hours, and 4–6 months after surgery. The data show that TKA patients had a higher likelihood of developing persistent post-surgical pain, of reporting higher pain levels, and of using more neuropathic descriptors when classifying their pain. In addition, TKA patients more often reported interference from pain on functional domains, including general activity, walking ability, and normal work. Demographic factors, like gender and age, along with presurgical clinical factors like disease onset, existence of medical comorbidities, and other pain problems, may have contributed to these differences, whereas baseline psychologic factors and functionality levels did not seem to exert an influence. Heightened acute post-surgical pain experience among TKA patients could also be related to distinct outcomes for persistent post-surgical pain. Future prospective studies should therefore collect TKA and THA samples wherein patients are homogeneous for demographic and presurgical clinical issues. Overall, these findings contribute to a small but growing body of literature documenting persistent post-surgical pain after major arthroplasty, conducted in different countries and across different health care settings. PMID:24072977
The effect of experimental muscle pain on the amplitude and velocity sensitivity of jaw closing muscle spindle afferents.
Masri, Radi; Ro, Jin Y; Capra, Norman
The effect of experimental muscle pain on the amplitude and velocity sensitivity of muscle spindle primary afferent neurons in the trigeminal mesencephalic nucleus (Vmes) was examined. Extracellular recordings were made from 45 neurons designated as spindle primary- or secondary-like on the basis of their response to ramp-and-hold jaw movements. Velocity sensitivity was assessed in spindle primary-like afferents by calculating the mean dynamic index of each unit in response to three different velocities of jaw opening before and after intramuscular injection with hypertonic saline (HS, 5%, 100 microl). The amplitude sensitivity of all jaw muscle spindle afferents was assessed by calculating the mean firing rate of each unit in response to three different amplitudes of jaw openings during both the open and hold phases of the movement and with best-fit lines obtained, using linear regression analysis, before and after HS injection. The variance of the two regression lines obtained for each unit before and after the injection was compared using the coincidence test, and changes in intercept and slope were determined. Seventy-five percent of the primary-like units and 80% of the secondary-like units presented with changes in static behavior after HS injection. Thirty-six percent of the primary-like units showed changes in dynamic behavior. Injection of isotonic saline (control) did not alter the responses of the spindle afferent to jaw opening. Thus, our results demonstrate that the predominant effect of noxious stimulation was a shift in the amplitude sensitivity of both spindle primary-like and secondary-like afferents and, to a lesser extent, the velocity sensitivity of the spindle primary-like unit. In accordance with earlier studies in the cat hindlimb and neck muscles, these results suggest that the activation of masseter muscle nociceptor alters spindle afferent responses to stretch acting primarily through static gamma motor neurons.
The effectiveness of virtual reality for dental pain control: a case study.
Hoffman, H G; Garcia-Palacios, A; Patterson, D R; Jensen, M; Furness, T; Ammons, W F
The present study explored whether immersive virtual reality can serve as an effective non-pharmacologic analgesic for dental pain. Two patients (aged 51 and 56 years old) with adult periodontitis, a chronic, progressive inflammatory disease that affects gums, ligaments, and bones around the teeth, were studied in the treatment room of a periodontist. Each patient received periodontal scaling and root planing (scraping off/removing plaque deposits below the gum line, hereafter referred to as scaling) under three treatment conditions: (1) virtual reality distraction, (2) movie distraction, and (3) a no-distraction control condition. Condition order was randomized and counterbalanced. For each of the three treatment conditions, five visual analog pain scores for each treatment condition served as the dependent variables. On 0-10 labeled scales, both patients provided sensory and affective pain ratings, and subjective estimates of time spent thinking about his pain during the procedure. For patient 1, mean pain ratings were in the severe range while watching a movie (7.2), or no distraction (7.2) but in the mild pain range (1.2) during the VR condition. Patient 2 reported mild to moderate pain with no distraction (mean = 4.4), mild pain while watching the movie (3.3), and essentially no pain while in VR (0.6) during his periodontal scaling. Although the small sample size limits generalizability, we contend that virtual reality is a uniquely attention-grabbing medium capable of maximizing the amount of attention drawn away from the "real world," allowing patients to tolerate painful dental procedures. These preliminary results suggest that immersive VR merits more attention as a potentially viable adjunctive nonpharmacologic analgesia for procedural dental/periodontal pain. Virtual reality may also have analgesic potential for other painful procedures or pain populations. Practical implications are discussed.
The Cognitive Functions in Adults with Chronic Pain: A Comparative Study
Jasem, Zainab; Manee, Fahad S.
Background. Several studies have reported an association between chronic pain and reduction of cognitive abilities of adults living in Western cultures. No literature could be found on the relationship between chronic pain and cognition among Middle Eastern adults. Objective. To compare four of the most commonly reported cognitive domains [memory, attention, processing speed, and executive functioning] among Middle Eastern adults with and without chronic pain. Methods. This matched group comparative study included 69 community residing and functionally independent Middle Eastern adults. Forty participants had chronic pain and 29 were pain-free. We administered five standardized cognitive assessments that are independent of culture and language to measure variable tasks of memory, attention, processing speed, and executive functioning. The study was conducted in a rehabilitation research setting with a controlled environment. Results. Evidence of decreased cognitive processing was found in patients with chronic pain. The chronic pain participants performed significantly worse than the pain-free participants on the cognitive measures of long-term memory, selective attention, processing speed, and executive functioning. Conclusion. The effect of Middle Eastern culture on the cognitive abilities of patients with chronic pain was negligible. Despite the wide variations between Eastern and Western cultures, the performance of our Middle Eastern participants in this study was consistent with performance of Western adults reported in previous studies. PMID:28127233
Studying sex and gender differences in pain and analgesia: A consensus report
Greenspan, Joel D.; Craft, Rebecca M.; LeResche, Linda; Arendt-Nielsen, Lars; Berkley, Karen J.; Fillingim, Roger B.; Gold, Michael S.; Holdcroft, Anita; Lautenbacher, Stefan; Mayer, Emeran A.; Mogil, Jeffrey S.; Murphy, Anne Z.; Traub, Richard J.
In September 2006, members of the Sex, Gender and Pain Special Interest Group of the International Association for the Study of Pain met to discuss the following: (1) what is known about sex and gender differences in pain and analgesia; (2) what are the "best practice" guidelines for pain research with respect to sex and gender; and (3) what are the crucial questions to address in the near future? The resulting consensus presented herein includes input from basic science, clinical and psychosocial pain researchers, as well as from recognized experts in sexual differentiation and reproductive endocrinology. We intend this document to serve as a utilitarian and thought-provoking guide for future research on sex and gender differences in pain and analgesia, both for those currently working in this field as well as those still wondering, "Do I really need to study females?" PMID:17964077
Whole body vibration therapy for painful diabetic peripheral neuropathy: a pilot study.
Kessler, Nathan J; Hong, Junggi
The unsatisfactory results associated with conventional treatments for symptoms of diabetic peripheral neuropathy (DPN) demonstrate a need for research into alternative therapies. The purpose of this study was to determine the efficacy of whole body vibration therapy (WBV) as a treatment for pain associated with DPN. Participants (n = 8) with painful DPN received three treatment sessions per week for four weeks. Each session consisted of four bouts of 3 min of vibration (frequency 25 Hz, amplitude 5 mm). The primary outcome measures were changes in the visual analog pain scale (VAS) and changes in the neuropathic pain scale (NPS). WBV demonstrated a significant (p < 0.05) acute pain reduction in the VAS, and a significant chronic reduction in both the VAS and NPS scales. No side-effects were observed during this study. WBV appears to be an effective, non-invasive treatment for pain associated with DPN.
Can consistent benchmarking within a standardized pain management concept decrease postoperative pain after total hip arthroplasty? A prospective cohort study including 367 patients
Benditz, Achim; Greimel, Felix; Auer, Patrick; Zeman, Florian; Göttermann, Antje; Grifka, Joachim; Meissner, Winfried; von Kunow, Frederik
Background The number of total hip replacement surgeries has steadily increased over recent years. Reduction in postoperative pain increases patient satisfaction and enables better mobilization. Thus, pain management needs to be continuously improved. Problems are often caused not only by medical issues but also by organization and hospital structure. The present study shows how the quality of pain management can be increased by implementing a standardized pain concept and simple, consistent, benchmarking. Methods All patients included in the study had undergone total hip arthroplasty (THA). Outcome parameters were analyzed 24 hours after surgery by means of the questionnaires from the German-wide project "Quality Improvement in Postoperative Pain Management" (QUIPS). A pain nurse interviewed patients and continuously assessed outcome quality parameters. A multidisciplinary team of anesthetists, orthopedic surgeons, and nurses implemented a regular procedure of data analysis and internal benchmarking. The health care team was informed of any results, and suggested improvements. Every staff member involved in pain management participated in educational lessons, and a special pain nurse was trained in each ward. Results From 2014 to 2015, 367 patients were included. The mean maximal pain score 24 hours after surgery was 4.0 (±3.0) on an 11-point numeric rating scale, and patient satisfaction was 9.0 (±1.2). Over time, the maximum pain score decreased (mean 3.0, ±2.0), whereas patient satisfaction significantly increased (mean 9.8, ±0.4; p<0.05). Among 49 anonymized hospitals, our clinic stayed on first rank in terms of lowest maximum pain and patient satisfaction over the period. Conclusion Results were already acceptable at the beginning of benchmarking a standardized pain management concept. But regular benchmarking, implementation of feedback mechanisms, and staff education made the pain management concept even more successful. Multidisciplinary teamwork
The study of predicting role of personality traits in the perception of labor pain
Yadollahi, Parvin; Khalaginia, Zohreh; Vedadhir, Abouali; Ariashekouh, Arezoo; Taghizadeh, Ziba; Khormaei, Farhad
Background: Labor pain is one of the most intense pains experienced by women. Different factors including physiological, psychological, socio-cultural, environmental, and personality-related factors are relevant to perception of childbirth pain. The negative experience of pain causes mental, psychological problems and influences the relationship between the mother and infant. Therefore, considering the importance of women's health, this study was conducted to examine the predicting role of personality traits on perception of labor pain among pregnant women in Kazeroun, Fars Province, Iran. Materials and Methods: This study is a correlational descriptive–analytical study. The data were collected using big five factors questionnaire about personality traits (neuroticism, openness experience, agreeableness, conscientiousness, and extraversion) and a researcher-made questionnaire on the perception of labor pain (containing items such as reaction to pain, pain intolerance, pain depth, and pain acceptance) from 220 parturient women who referred to Valiasr Hospital in Kazeroun. The data were analyzed using statistical methods including Pearson correlation coefficient, factor analysis, and multiple regression analysis. All analyses were carried out with SPSS. Results: The results of the study indicated that among the factors influencing the perception of labor pain, the reaction to pain was meaningfully predicted by the personality dimensions of neuroticism (β =0.26, P < 0.01) and openness experience (β =0.20, P < 0.05). Neuroticism (β =0.20, P < 0.05) and openness experience (β =0.20, P < 0.05) were the positive predicting factors and conscientiousness (β = −0.20, P < 0.05) was a negative predicting factor for labor pain intolerance. Agreeableness (β =0.31, P < 0.01), neuroticism (β =0.20, P < 0.01), and openness experience (β =0.18, P < 0.01) were the predictive factors for pain depth. Among all personality traits, neuroticism (β =0.19, P < 0.05) and
Cultural responses to pain in UK children of primary school age: a mixed-methods study.
Azize, Pary M; Endacott, Ruth; Cattani, Allegra; Humphreys, Ann
Pain-measurement tools are often criticized for not addressing the influence of culture and ethnicity on pain. This study examined how children who speak English as a primary or additional language discuss pain. Two methods were used in six focus group interviews with 34 children aged 4-7 years: (i) use of drawings from the Pediatric Pain Inventory to capture the language used by children to describe pain; and (ii) observation of the children's placing of pain drawings on red/amber/green paper to denote perceived severity of pain. The findings demonstrated that children with English as an additional language used less elaborate language when talking about pain, but tended to talk about the pictures prior to deciding where they should be placed. For these children, there was a positive significant relationship between language, age, and length of stay in the UK. The children's placement of pain drawings varied according to language background, sex, and age. The findings emphasize the need for sufficient time to assess pain adequately in children who do not speak English as a first language.
Prospective clinical observational study evaluating gender-associated differences of preoperative pain intensity
Tafelski, Sascha; Kerper, Léonie F; Salz, Anna-Lena; Spies, Claudia; Reuter, Eva; Nachtigall, Irit; Schäfer, Michael; Krannich, Alexander; Krampe, Henning
Abstract Previous studies reported conflicting results concerning different pain perceptions of men and women. Recent research found higher pain levels in men after major surgery, contrasted by women after minor procedures. This trial investigates differences in self-reported preoperative pain intensity between genders before surgery. Patients were enrolled in 2011 and 2012 presenting for preoperative evaluation at the anesthesiological assessment clinic at Charité University hospital. Out of 5102 patients completing a computer-assisted self-assessment, 3042 surgical patients with any preoperative pain were included into this prospective observational clinical study. Preoperative pain intensity (0–100 VAS, visual analog scale) was evaluated integrating psychological cofactors into analysis. Women reported higher preoperative pain intensity than men with median VAS scores of 30 (25th–75th percentiles: 10–52) versus 21 (10–46) (P < 0.001). Adjusted multiple regression analysis showed that female gender remained statistically significantly associated with higher pain intensity (P < 0.001). Gender differences were consistent across several subgroups especially with varying patterns in elderly. Women scheduled for minor and moderate surgical procedures showed largest differences in overall pain compared to men. This large clinical study observed significantly higher preoperative pain intensity in female surgical patients. This gender difference was larger in the elderly potentially contradicting the current hypothesis of a primary sex-hormone derived effect. The observed variability in specific patient subgroups may help to explain heterogeneous findings of previous studies. PMID:27399095
Occupational-related back pain among Jordanian nurses: A descriptive study.
Shawashi, Tagreed O; Subih, Maha M; Al Hadid, Lourance Abdel Razzaq; Abu Adas, Mohammad
Back pain is the leading cause of disability, decreased physical performance at work and absenteeism. Activities leading to the occurrence of back pain include patient transfer and long standing hours. This study aimed to explore the prevalence and determine the activities responsible for the presence of back pain among Jordanian nurses. A descriptive cross-sectional study was conducted on a convenience sample of nurses from governmental hospitals in Jordan. A self-report questionnaire was developed by Stubbs et al. and Harber et al. A descriptive method using mean, standard deviations and percentages was used, in addition to chi-square tests. Baseline findings indicated that more than three-quarters of the nurses studied suffered back pain during their work. Among nurses with back pain, about a fifth of them reported it to administration. The highest percentage of back pain was among critical care nurses. Further, the static factors contributed less commonly to back pain compared with the dynamic factors. Nearly half the participants with back pain reported taking days off more frequently. Jordanian nurses demonstrated one of the highest frequencies of back pain compared with other studies. Focus should be placed on education programmes about the appropriate body mechanics.
Groin pain following hip resurfacing: a case-control study.
McArthur, John R; Costa, Matthew; Griffin, Damian R; Krikler, Steven J; Parsons, Nicholas; Foguet, Pedro R
We compared 47 patients with groin pain following hip resurfacing to a matched control group. Functional scores and plain radiographs were assessed along with measurement of whole blood cobalt and chromium by inductively coupled mass spectrometry. Symptomatic patients underwent ultrasound scan of the affected hip. Mean functional outcomes were poor in those with pain and good in the control group. Groin pain was associated with valgus stem positioning and lower neck:head ratio (relatively narrow neck) (p=0.03, p=0.04 respectively). We classified patients with groin pain into two groups: biological and mechanical. The biological group had soft tissue abnormalities on USS and higher levels of cobalt and chromium (p=0.04, p=0.05 respectively). The mechanical group had normal USS, lower metal ion levels and more retroverted femoral components (p=0.01).
Course and prognosis of older back pain patients in general practice: a prospective cohort study.
Scheele, Jantine; Enthoven, Wendy T M; Bierma-Zeinstra, Sita M A; Peul, Wilco C; van Tulder, Maurits W; Bohnen, Arthur M; Berger, Marjolein Y; Koes, Bart W; Luijsterburg, Pim A J
The aim of the current study was to determine the course of back pain in older patients and identify prognostic factors for non-recovery at 3 months' follow-up. We conducted a prospective cohort study (the BACE study) of patients aged >55 years visiting a general practitioner (GP) with a new episode of back pain in the Netherlands. The course of back pain was described in terms of self-perceived recovery, pain severity, disability, pain medication, and GP visits at 6 weeks' and 3 months' follow-up. Prognostic factors for non-recovery at 3 months' follow-up were derived from the baseline questionnaire and physical examination. Variables with a prognostic value were identified with multivariable logistic regression analysis (method backward), and an area under the receiver operating curve (AUC) was calculated for the prognostic model. A total of 675 back pain patients (mean age 66.4 (SD 7.6) years) participated in the BACE cohort study. At 6 weeks' follow-up 64% of the patients reported non-recovery from back pain. At 3 months' follow-up 61% still reported non-recovery, but only 26% of these patients had revisited the GP. Longer duration of the back pain, severity of back pain, history of back pain, absence of radiating pain in the leg below the knee, number of comorbidities, patients' expectation of non-recovery, and a longer duration of the timed 'Up and Go' test were significantly associated with non-recovery in a multiple regression model (AUC 0.79). This information can help GPs identify older back pain patients at risk for non-recovery.
Effect of catechol-O-methyltransferase polymorphism on response to propranolol therapy in chronic musculoskeletal pain: A randomized, double–blind, placebo-controlled, crossover pilot study
Tchivileva, Inna E.; Lim, Pei Feng; Smith, Shad B.; Slade, Gary D.; Diatchenko, Luda; McLean, Samuel A.; Maixner, William
Introduction Three common haplotypes in the gene encoding catechol-O-methyltransferase (COMT) have been associated with pain modulation and the risk of developing chronic musculoskeletal pain, namely temporomandibular disorder (TMD). Haplotypes coding for higher enzymatic activity were correlated with lower pain perception. Rodent studies showed that COMT inhibition increases pain sensitivity via β2/3-adrenergic receptors. We hypothesized that the non-selective β-adrenergic antagonist propranolol will reduce clinical and experimental pain in TMD patients in a manner dependent on the subjects' COMT diplotype. Methods 40 female Caucasian participants meeting the Research Diagnostic Criteria for TMD were genotyped for COMT polymorphisms and completed a randomized, double–blind, placebo-controlled, two-period crossover pilot study. Each period consisted of a baseline assessment week followed by an intervention week (propranolol or placebo). Changes in clinical pain ratings, psychological status, and responses to heat and pressure stimuli between baseline and intervention weeks were compared across periods. Results The number of patients reporting a reduction in pain intensity rating was greater during propranolol treatment (p=0.014) compared with placebo. Propranolol significantly reduced a composite pain index (p=0.02) but did not decrease other clinical and experimental pain ratings. When stratified by the COMT high activity haplotype, a beneficial effect of propranolol on pain perception was noted in subjects not carrying this haplotype, a diminished benefit was observed in the heterozygotes, and no benefit was noted in the homozygotes. Conclusion COMT haplotypes may serve as genetic predictors of propranolol treatment outcome, identifying a subgroup of TMD patients who will benefit from propranolol therapy. PMID:20216107
Pain and risk of completed suicide in Japanese men: a population-based cohort study in Japan (Ohsaki Cohort Study).
Kikuchi, Nobutaka; Ohmori-Matsuda, Kaori; Shimazu, Taichi; Sone, Toshimasa; Kakizaki, Masako; Nakaya, Naoki; Kuriyama, Shinichi; Tsuji, Ichiro
Unrelieved pain is a major factor that influences suicide risk among terminally ill patients, but little is known about the relationship between pain and the risk of completed suicide in the general population. We prospectively examined the association between self-reports of pain and subsequent risk of completed suicide in 26,481 men aged 40 to 79 years from the Ohsaki National Health Insurance Cohort study, a population-based, prospective cohort study initiated in 1994. On the basis of a five-item questionnaire on pain, individuals were classified as having no pain, very mild pain, mild pain, or moderate or severe pain. Completed suicide cases were documented from 1995 to 2001. During 131,027 person-years, 64 completed suicides were documented. After adjustment for covariates, the risk for completed suicide was significantly higher in the subjects with more pain. Multivariate hazard ratios (95% confidence intervals) relative to the subjects who had no pain were 1.36 (0.67-2.75), 2.11 (1.02-4.33), and 2.93 (1.34-6.42) in the subjects who had very mild pain, mild pain, and moderate or severe pain, respectively (P for trend=0.004). Stratified analysis showed that the positive association between pain and suicide risk was robust in the subjects with good health, low stress, adequate sleep, good physical activity, and no history of chronic diseases. Our results suggest that pain is associated with an increased risk of completed suicide among Japanese men. The association was consistently observed among apparently healthy subjects.
Pregnancy related back pain, is it related to aerobic fitness? A longitudinal cohort study
Background Low back pain with onset during pregnancy is common and approximately one out of three women have disabling pain. The pathogenesis of the pain condition is uncertain and there is no information on the role of physical fitness. Whether poorer physical conditioning is a cause or effect of back pain is also disputed and information from prospective studies needed. Methods A cohort of pregnant women, recruited from maternal health care centers in central Sweden, were examined regarding estimated peak oxygen uptake by cycle ergometer test in early pregnancy, reported physical activity prior to pregnancy, basic characteristics, back pain during pregnancy and back pain postpartum. Results Back pain during the current pregnancy was reported by nearly 80% of the women. At the postpartum appointment this prevalence was 40%. No association was displayed between estimated peak oxygen uptake and incidence of back pain during and after pregnancy, adjusted for physical activity, back pain before present pregnancy, previous deliveries, age and weight. A significant inverse association was found between estimated peak oxygen uptake and back pain intensity during pregnancy and a direct association post partum, in a fully adjusted multiple linear regression analysis. Conclusions Estimated peak oxygen uptake and reported physical activity in early pregnancy displayed no influence on the onset of subsequent back pain during or after pregnancy, where the time sequence support the hypothesis that poorer physical deconditioning is not a cause but a consequence of the back pain condition. The mechanism for the attenuating effect of increased oxygen uptake on back pain intensity is uncertain. PMID:22510295
A prospective study of neuropathic pain induced by thoracotomy: incidence, clinical description, and diagnosis.
Guastella, Virginie; Mick, Gérard; Soriano, Christophe; Vallet, Laurent; Escande, Georges; Dubray, Claude; Eschalier, Alain
This study evaluated prospectively the incidence of neuropathic pain after thoracotomy, described its clinical characteristics, and delineated landmarks for its diagnosis in daily practice. We evaluated clinically painful symptoms and sensory deficits in 54 patients after lateral/posterolateral thoracotomy for broncho-pulmonary carcinoma with standardized surgical and analgesic procedures. At 2months, 49 patients suffered from non malignant thoracic pain, and at 6months 38 patients (loss to follow-up for 7) reported persisting pain. In 35 patients, painful symptoms and sensory deficits could be evaluated using a standardized clinical bedside procedure. According to the grading system proposed by Treede et al. [41], neuropathic pain was considered probable in 21 patients, while use of the DN4 questionnaire concluded that neuropathic pain was probable in 17 patients. The two diagnostic procedures provided similar conclusions in 16 patients. Morphine consumption during the early post-operative period (mean 111.3±30.8mg/day) and pain intensity (VAS: mean 5.71±2.1) were significantly higher in patients suffering from neuropathic pain than in other patients with pain (mean 80±21.4mg/day; VAS: mean 3.9±2.4). The clinical picture in most patients with neuropathic pain included electric shocks and severe multimodal hypoesthesia in the sensory area of 5th/6th intercostal nerves. Thus, our results indicate a minimal incidence of chronic post-thoracotomy pain at 70% and that of neuropathic pain at 29%, this latter being clinically suggested by a combination of certain symptoms and reinforced by the DN4 questionnaire when sensory deficit at scar is present.
Long-term trajectories of back pain: cohort study with 7-year follow-up
Dunn, Kate M; Campbell, Paul; Jordan, Kelvin P
Objective To describe long-term trajectories of back pain. Design Monthly data collection for 6 months at 7-year follow-up of participants in a prospective cohort study. Setting Primary care practices in Staffordshire, UK. Participants 228 people consulting their general practitioners with back pain, on whom information on 6-month back pain trajectories had been collected during 2001–2003, and who had valid consent and contact details in 2009–2010, were contacted. 155 participants (68% of those contacted) responded and provided sufficient data for primary analyses. Outcome measures Trajectories based on patients' self-reports of back pain were identified using longitudinal latent class analysis. Trajectories were characterised using information on disability, psychological status and presence of other symptoms. Results Four clusters with different back pain trajectories at follow-up were identified: (1) no or occasional pain, (2) persistent mild pain, (3) fluctuating pain and (4) persistent severe pain. Trajectory clusters differed significantly from each other in terms of disability, psychological status and other symptoms. Most participants remained in a similar trajectory as 7 years previously (weighted κ 0.54; 95% CI 0.42 to 0.65). Conclusions Most people with back pain appear to follow a particular pain trajectory over long time periods, and do not have frequently recurring or widely fluctuating patterns. The results are limited by lack of information about the time between data collection periods and by loss to follow-up. However, findings do raise questions about standard divisions into acute and chronic back pain. A new framework for understanding the course of back pain is proposed. PMID:24334157
Effect of Music Therapy on Pain and Anxiety Levels of Cancer Patients: A Pilot Study
Krishnaswamy, Priyadharshini; Nair, Shoba
Background: The pain associated with cancer is highly detrimental to the quality of life of the affected individuals. It also contributes to the anxiety of the patient. There is a need for a nonpharmacological approach in addition to the pharmacological therapy for the management of the pain for a more holistic improvement in the individual. With this study, we wish to achieve this through music. Objective: To assess the effect of music therapy on pain scores and anxiety levels of cancer patients with pain. Study Design: In this quantitative study, a comparative study was done on fourteen cancer patients admitted for pain relief under the Department of Pain and Palliative Medicine, of a tertiary care hospital, having moderate to severe pain (numerical pain rating scale [NRS] – of 4 to 10). Subjects and Methods: Convenience sampling was used. Patients were allocated to test group or control group nonrandomly. The test group patients were subjected to music therapy for 20 min while the control group patients were kept occupied by talking to them for 20 min. The NRS scale was used to assess the pre- and post-interventional pain scores and the Hamilton anxiety rating scale was used to assess the pre- and post-interventional anxiety scores in the two groups. Statistics: Student's t-test was used for comparing the pre- and post-interventional data. Two sample t-test was used to compare the data obtained from the control and study groups. Results: Statistically significant reduction seen in the pain scores in the test group after music therapy (P = 0.003). No statistically significant reduction seen in the pain score in the control group (P = 0.356). There was a statistically significant reduction in the postintervention pain scores in the test group compared to the control group (P = 0.034). The reduction in anxiety levels in both groups after intervention was not statistically significant. Conclusion: Music therapy was found to lower the pain score of a patient who
Efficacy of fentanyl transdermal patch in pain control after lower third molar surgery: A preliminary study
Vasovic, Miroslav; Andric, Miroslav; Todorovic, Ljubomir; Kokovic, Vladimir
Background Surgical removal of impacted lower third molars is a common oral surgical procedure, generally followed by moderate to severe postoperative pain. Transdermal drug delivery as a concept offers interesting possibilities for postoperative pain control. The aim of this study was to evaluate the efficacy of transdermal system with fentanyl in relieving pain following impacted lower third molar surgery. Material and Methods Seventeen patients with bilateral impacted lower third molars were included in this preliminary study. For postoperative pain control, patients randomly received a fentanyl patch plus placebo tablet after the first operation and regular (placebo) patch and an analgesic, after the second operation. Analgesia was evaluated during first 24 hours postoperatively according to patients' reports about time of first pain appearance and additional analgesic consumption. Pain severity was rated using a 10 cm long visual analogue scale (VAS). Results Intensity of postoperative pain and postoperative analgesic consumption were significantly lower after the Fentanyl Transdermal System (FTS) was applied (p<0.05). Duration of postoperative analgesia was significantly higher with FTS when compared to control treatment (p<0.05). Conclusions Based on the results of this preliminary study, transdermal system with fentanyl significantly reduced postoperative pain after third molar surgery. Key words:Analgesia, fentanyl, transdermal administration, third molar surgery, acute pain, postoperative care. PMID:27475691
Pain in children and adults with cystic fibrosis: a comparative study.
Sermet-Gaudelus, Isabelle; De Villartay, Philippe; de Dreuzy, Pascaline; Clairicia, Marléne; Vrielynck, Stéphanie; Canoui, Pierre; Kirzsenbaum, Maya; Singh-Mali, Isabelle; Agrario, Line; Salort, Muriel; Charron, Brigitte; Dusser, Daniel; Lenoir, Gerard; Hubert, Dominique
Pain is a potential complication of cystic fibrosis (CF), but its consequences in daily life and other issues of pain management are not yet clearly understood. We undertook a comparative study of children and adults with CF to assess the prevalence of pain symptoms, their characteristics and treatment, their impact on daily quality of life, and the occurrence of procedural pain. The study included 73 children (1-18 years) and 110 adults (18-52 years); 59% of the children and 89% of the adults reported at least one episode of pain during the previous month. Pain was significantly more intense and lasted significantly longer among adults, but its rate and recurrence did not differ significantly between the two populations and were not related to the severity of CF. The most prevalent locations were the abdomen for children, and the back, head, and chest for adults. Although pain significantly limited physical activity, only 15% of patients reported that it caused absenteeism, and 27% reported that it negatively affected their family life. The mean pain intensity rates on a visual analog scale for the episode that had caused the greatest pain during the past month were 4.9 (2) (mean [SD]) for children and 6 (2) for adults; however, only 40% and 50%, respectively, of those with pain reported the use of analgesic treatment, mainly paracetamol (acetaminophen). At least one episode of procedural pain during the previous month was reported by 85% of children and 78% of adults. Our study demonstrates the high incidence of undertreated pain in CF patients throughout their lives.
Mindful Yoga Pilot Study Shows Modulation of Abnormal Pain Processing in Fibromyalgia Patients.
Carson, James W; Carson, Kimberly M; Jones, Kim D; Lancaster, Lindsay; Mist, Scott D
Published findings from a randomized controlled trial have shown that Mindful Yoga training improves symptoms, functional deficits, and coping abilities in individuals with fibromyalgia and that these benefits are replicable and can be maintained 3 months post-treatment. The aim of this study was to collect pilot data in female fibromyalgia patients (n = 7) to determine if initial evidence indicates that Mindful Yoga also modulates the abnormal pain processing that characterizes fibromyalgia. Pre- and post-treatment data were obtained on quantitative sensory tests and measures of symptoms, functional deficits, and coping abilities. Separation test analyses indicated significant improvements in heat pain tolerance, pressure pain threshold, and heat pain after-sensations at post-treatment. Fibromyalgia symptoms and functional deficits also improved significantly, including physical tests of strength and balance, and pain coping strategies. These findings indicate that further investigation is warranted into the effect of Mindful Yoga on neurobiological pain processing.
Mindful Yoga Pilot Study Shows Modulation of Abnormal Pain Processing in Fibromyalgia Patients.
Carson, James W; Carson, Kimberly M; Jones, Kim D; Lancaster, Lindsay; Mist, Scott D
Published findings from a randomized controlled trial have shown that Mindful Yoga training improves symptoms, functional deficits, and coping abilities in individuals with fibromyalgia and that these benefits are replicable and can be maintained 3 months post-treatment. The aim of this study was to collect pilot data in female fibromyalgia patients (n = 7) to determine if initial evidence indicates that Mindful Yoga also modulates the abnormal pain processing that characterizes fibromyalgia. Pre- and post-treatment data were obtained on quantitative sensory tests and measures of symptoms, functional deficits, and coping abilities. Separation test analyses indicated significant improvements in heat pain tolerance, pressure pain threshold, and heat pain after-sensations at post-treatment. Fibromyalgia symptoms and functional deficits also improved significantly, including physical tests of strength and balance, and pain coping strategies. These findings indicate that further investigation is warranted into the effect of Mindful Yoga on neurobiological pain processing.
[Vibration, back pain and physical exercise in high-risk professionals: a cross-sectional study].
Valenti, M; Prosperini, V; Falzano, P; Hendel, M; Raimondi, P
Repeated loads and vibration stress in professional settings are relevant risk factors for back pain. Aim of this cross-sectional study was to estimate: a) the prevalence of back pain in two high-risk professional samples (helicopter pilots and bus drivers); b) the association between physical/sports exercise and back pain subjective perception across age. Prevalence of back pain is 94% in helicopter pilots and 74% in bus drivers; prevalence of back pain significantly increases with age. The positive effect of regular physical/sports exercise on subjective back pain significantly decreases with age. Physical or sports exercise adapted to structural characteristic of patients can result effective in diminishing personal impairment in subjects at professional risk.
A Pilot Study of the Prevalence of Leg Pain Among Women with Endometriosis
Missmer, Stacey A.; Bove, Geoffrey M.
Radiating leg pain is a common symptom presenting in manual therapy practices. Although this symptom has been reported as a complication of endometriosis, its prevalence and characteristics have not been studied. We surveyed members of a national endometriosis support group with endometriosis using a self-administered, mailed questionnaire. The main outcome measures were the prevalence and characteristics of leg pain. Of 94 respondents, leg pain was reported by 48 women (51%), and was bilateral in 59% of these symptomatic women. The likelihood of experiencing leg pain was related to weight gain since age 18, age, and height. The most common treatments tried included exercise, over-the-counter medications, and massage therapy, all with variable results. These data support leg pain as a prevalent complication of endometriosis, and that the disease may affect multiple peripheral nerves. Manual therapists should remain aware to this possible etiology for radiating pain. PMID:21665106
A pilot study of the prevalence of leg pain among women with endometriosis.
Missmer, Stacey A; Bove, Geoffrey M
Radiating leg pain is a common symptom presenting in manual therapy practices. Although this symptom has been reported as a complication of endometriosis, its prevalence and characteristics have not been studied. We surveyed members of a national endometriosis support group with endometriosis using a self-administered, mailed questionnaire. The main outcome measures were the prevalence and characteristics of leg pain. Of 94 respondents, leg pain was reported by 48 women (51%), and was bilateral in 59% of these symptomatic women. The likelihood of experiencing leg pain was related to weight gain since age 18, age, and height. The most common treatments tried included exercise, over-the-counter medications, and massage therapy, all with variable results. These data support leg pain as a prevalent complication of endometriosis, and that the disease may affect multiple peripheral nerves. Manual therapists should remain aware to this possible etiology for radiating pain.
Study protocol title: a prospective cohort study of low back pain
Background Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors. Methods/design A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs. Due to the subjectivity of LBP, six measures of LBP are captured: 1) any LBP, 2) LBP ≥ 5/10 pain rating, 3) LBP with medication use, 4) LBP with healthcare provider visits, 5) LBP necessitating modified work duties and 6) LBP with lost work time. Workers have thus far been enrolled from 30 different employment settings in 4 diverse US states and performed widely varying work. At baseline, workers undergo laptop-administered questionnaires, structured interviews, and two standardized physical examinations to ascertain demographics, medical history, psychosocial factors, hobbies and physical activities, and current musculoskeletal disorders. All workers' jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of low back pain. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. The lifetime cumulative incidence of low back pain will also include those with a past history of low back pain. Incident cases will exclude prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression. Discussion Data analysis of a prospective cohort study of low back pain is underway and has successfully enrolled over 800 workers to date. PMID:23497211
Efficacy and Safety of Acupuncture for Acute Low Back Pain in Emergency Department: A Pilot Cohort Study.
Liu, Yen-Ting; Chiu, Chih-Wen; Chang, Chin-Fu; Lee, Tsung-Chieh; Chen, Chia-Yun; Chang, Shun-Chang; Lee, Chia-Ying; Lo, Lun-Chien
Introduction. Low back pain (LBP) is one of the most common complaints in the emergency department (ED). There are several research articles providing evidence for acupuncture for treating chronic LBP but few about treating acute LBP. This study assessed the efficacy and safety of acupuncture for the treatment of acute LBP in the ED. Materials and methods. A clinical pilot cohort study was conducted. 60 participants, recruited in the ED, were divided into experimental and control groups with 1 dropout during the study. Life-threatening conditions or severe neurological defects were excluded. The experimental group (n = 45) received a series of fixed points of acupuncture. The control group (n = 14) received sham acupuncture by pasting seed-patches near acupoints. Back pain was measured using the visual analog scale (VAS) at three time points: baseline and immediately after and 3 days after intervention as the primary outcome. The secondary outcomes were heart rate variability (HRV) and adverse events. Results. The VAS demonstrated a significant decrease (P value <0.001) for the experimental group after 15 minutes of acupuncture. The variation in HRV showed no significant difference in either group. No adverse event was reported. Conclusion. Acupuncture might provide immediate effect in reducing the pain of acute LBP safely.
Efficacy and Safety of Acupuncture for Acute Low Back Pain in Emergency Department: A Pilot Cohort Study
Liu, Yen-Ting; Chiu, Chih-Wen; Chang, Chin-Fu; Lee, Tsung-Chieh; Chen, Chia-Yun; Chang, Shun-Chang; Lee, Chia-Ying; Lo, Lun-Chien
Introduction. Low back pain (LBP) is one of the most common complaints in the emergency department (ED). There are several research articles providing evidence for acupuncture for treating chronic LBP but few about treating acute LBP. This study assessed the efficacy and safety of acupuncture for the treatment of acute LBP in the ED. Materials and methods. A clinical pilot cohort study was conducted. 60 participants, recruited in the ED, were divided into experimental and control groups with 1 dropout during the study. Life-threatening conditions or severe neurological defects were excluded. The experimental group (n = 45) received a series of fixed points of acupuncture. The control group (n = 14) received sham acupuncture by pasting seed-patches near acupoints. Back pain was measured using the visual analog scale (VAS) at three time points: baseline and immediately after and 3 days after intervention as the primary outcome. The secondary outcomes were heart rate variability (HRV) and adverse events. Results. The VAS demonstrated a significant decrease (P value <0.001) for the experimental group after 15 minutes of acupuncture. The variation in HRV showed no significant difference in either group. No adverse event was reported. Conclusion. Acupuncture might provide immediate effect in reducing the pain of acute LBP safely. PMID:26346626
Medial tibial pain. A prospective study of its cause among military recruits.
Milgrom, C; Giladi, M; Stein, M; Kashtan, H; Margulies, J; Chisin, R; Steinberg, R; Swissa, A; Aharonson, Z
In a prospective study of 295 infantry recruits during 14 weeks of basic training, 41% had medial tibial pain. Routine scintigraphic evaluation in cases of medial tibial bone pain showed that 63% had abnormalities. A stress fracture was found in 46%. Only two patients had periostitis. None had ischemic medial compartment syndrome. Physical examination could not differentiate between cases with medial tibial bone pain secondary to stress fractures and those with scintigraphically normal tibias. When both pain and swelling were localized in the middle one-third of the tibia, the lesion most likely proved to be a stress fracture.
[Study of prevalence of pain at the Juan Canalejo Hospital in La Coruña].
Valero, J; Palacios, P; Vazquez-Barro, A; Lopez-Suso, E; Carpintero, D
A study of prevalence of pain conducted in 812 patients admitted in the Juan Canalejo Hospital in La Coruña (Spain). This is primarily an adult hospital. Of the 650 patients whose replies were deemed valid, 35.69% were suffering pain. Other findings were that the sociocultural level of the patients affected their assessment of pain and that 46.12% of those who were suffering pain were not receiving analgesics at that time. Magnesium dipyrone, a combination of paracetamol and codeine and morphine were the most commonly used drugs, although there was clearunderuse of analgesic.
An epidemiological study of low back pain in professional drivers
NASA Astrophysics Data System (ADS)
Bovenzi, Massimo; Rui, Francesca; Negro, Corrado; D'Agostin, Flavia; Angotzi, Giuliano; Bianchi, Sandra; Bramanti, Lucia; Festa, GianLuca; Gatti, Silvana; Pinto, Iole; Rondina, Livia; Stacchini, Nicola
The prevalence of low back pain (LBP) was investigated in 598 Italian professional drivers exposed to whole-body vibration (WBV) and ergonomic risk factors (drivers of earth moving machines, fork-lift truck drivers, truck drivers, bus drivers). The control group consisted of a small sample of 30 fire inspectors not exposed to WBV. Personal, occupational and health histories were collected by means of a structured questionnaire. Vibration measurements were performed on representative samples of the machines and vehicles used by the driver groups. From the vibration magnitudes and exposure durations, alternative measures of vibration dose were estimated for each subject. Daily vibration exposure, expressed in terms of 8-h energy-equivalent frequency-weighted acceleration, A(8), averaged 0.28-0.61 (range 0.10-1.18) m s -2 rms in the driver groups. Duration of exposure to WBV ranged between 1 and 41 years. The 7-day and 12-month prevalence of LBP was greater in the driver groups than in the controls. In the professional drivers, the occurrence of 12-month LBP, high intensity of LBP (Von Korff pain scale score ⩾5), and LBP disability (Roland & Morris disability scale score ⩾12) significantly increased with increasing cumulative vibration exposure. Even though several alternative measures of vibration exposure were associated with LBP outcomes, nevertheless a more regular trend of association with LBP was found for vibration dose expressed as ∑ a vit i (m s -2 h), in which the frequency-weighted acceleration, a v, and lifetime exposure duration, t, were given equal weight. In multivariate data analysis, individual characteristics (e.g. age, body mass index) and a physical load index (derived from combining manual materials handling and awkward postures) were significantly associated with LBP outcomes, while psychosocial work factors (e.g. job decision, job support) showed a marginal relation to LBP. This study tends to confirm that professional driving in industry
The Subjective Experience of Pain: an FMRI Study of Percept-related Models and Functional Connectivity
Wilcox, Claire E.; Mayer, Andrew R.; Teshiba, Terri M.; Ling, Josef; Smith, Bruce W.; Wilcox, George L.; Mullins, Paul G.
Objective Previous work suggests that the perception of pain is subjective and dependent on individual differences in physiological, emotional and cognitive states. Functional magnetic resonance imaging (FMRI) studies have utilized both stimulus-related (nociceptive properties) and percept-related (subjective experience of pain) models to identify the brain networks associated with pain. Our objective was to identify the network involved in processing subjective pain during cold stimuli. Methods The current FMRI study directly contrasted a stimulus-related model with a percept-related model during blocks of cold pain stimuli in healthy adults. Specifically, neuronal activation was modelled as a function of changes in stimulus intensity versus as a function of increasing/decreasing levels of subjective pain corresponding to changes in pain ratings. In addition, functional connectivity analyses were conducted to examine intrinsic correlations between three proposed sub-networks (sensory/discriminative, affective/motivational, and cognitive/evaluative) involved in pain processing. Results The percept-related model captured more extensive activation than the stimulus-related model and demonstrated an association between higher subjective pain and activation in expected cortical (DLPFC, VLPFC, insula, ACC extending into preSMA) and subcortical (thalamus, striatum) areas. Moreover, connectivity results supported the posited roles of dACC and insula as key relay sites during neural processing of subjective pain. In particular, anterior insula appeared to link sensory/discriminative regions with regions in the other sub-networks, and dACC appeared to serve as a hub for affective/motivational, cognitive/evaluative, and motor sub-networks. Conclusions Using a percept-related model, brain regions involved in the processing of subjective pain during the application of cold stimuli were identified. Connectivity analyses identified linkages between key sub-networks involved in
Distraction affects frontal alpha rhythms related to expectancy of pain: an EEG study.
Del Percio, Claudio; Le Pera, Domenica; Arendt-Nielsen, Lars; Babiloni, Claudio; Brancucci, Alfredo; Chen, Andrew C N; De Armas, Liala; Miliucci, Roberto; Restuccia, Domenico; Valeriani, Massimiliano; Rossini, Paolo Maria
Previous electroencephalographic (EEG) evidence has shown event-related desynchronization (ERD) of alpha rhythms before predictable painful stimuli, as a possible neural concomitant of attentional preparatory processes (Babiloni, C., Brancucci, A., Babiloni, F., Capotosto, P., Carducci, F., Cincotti, F., Arendt-Nielsen, L., Chen, A.C., Rossini, P.M., 2003. Anticipatory cortical responses during the expectancy of a predictable painful stimulation. A high-resolution electroencephalography study. Eur. J. Neurosci. 18 (6) 1692-700). This study tested the hypothesis that alpha ERD before predictable painful stimuli is reduced as an effect of distraction. A visual warning stimulus preceded a laser painful stimulation, which was strictly followed by visual imperative stimuli. In the Pain (control) condition, no task was required after the imperative stimuli. In the Pain + Movement condition, subjects had to perform a movement of the right index finger. In the Pain + Cognition condition, they had to mentally perform an arithmetical task. EEG data were recorded in 10 subjects from 30 electrodes. Artifact-free recordings were spatially enhanced by surface Laplacian transformation. Alpha ERD was computed at three alpha sub-bands according to subjects' individual alpha frequency peak (i.e., about 6-8 Hz, 8-10 Hz, 10-12 Hz). Compared to the control condition, the subjects reported a significantly lower stimulus intensity perception and unpleasantness in the Pain + Movement and Pain + Cognition conditions. In addition, there was a cancellation of the alpha 3 ERD (i.e., about 10-12 Hz) in Pain + Cognition condition and even a generation of a statistically significant alpha 3 ERS in Pain + Movement condition. These effects were maximum over fronto-central midline. These results suggest that distraction during the expectancy of pain is related to a reduced neural desynchronization of fronto-central midline alpha rhythms (i.e., reduced cortical activation) towards an overt hyper
Low Back Pain Response to Pelvic Tilt Position: An Observational Study of Chiropractic Patients
Minicozzi, Salvatore J.; Russell, Brent S.; Ray, Kathryn J.; Struebing, Alessandria Y.; Owens, Edward F.
Objective The aim of this study was to look for differences between patients with an increased pain response as compared with those with a decreased pain response. Methods Data were collected from consecutive new patients with lumbar or lumbopelvic pain in a chiropractic clinic. A pelvic tilt exercise was included in the initial examination, and pain response was noted. Analysis was made of pain and disability severity, as well as symptom location, chronicity, and other characteristics, before and after a course of chiropractic care. Results Patients with an increased pain response to pelvic tilt (n = 12) had higher levels of pain and disability at baseline than patients without (n = 34). There were no between-group differences in other aspects of their complaints; in age, sex, or body mass; or in the types of care they received (eg, manipulation, stretching, exercise instruction). On the average, both groups of patients showed improvement with chiropractic care, and there was no detectable difference in improvement between groups. Conclusions This study found that patients experiencing pain in response to a pelvic tilt maneuver may have a poorer precare status than patients with a decreased pain response. PMID:27069429
Pain intensity rating training: results from an exploratory study of the ACTTION PROTECCT system.
Smith, Shannon M; Amtmann, Dagmar; Askew, Robert L; Gewandter, Jennifer S; Hunsinger, Matthew; Jensen, Mark P; McDermott, Michael P; Patel, Kushang V; Williams, Mark; Bacci, Elizabeth D; Burke, Laurie B; Chambers, Christine T; Cooper, Stephen A; Cowan, Penney; Desjardins, Paul; Etropolski, Mila; Farrar, John T; Gilron, Ian; Huang, I-zu; Katz, Mitchell; Kerns, Robert D; Kopecky, Ernest A; Rappaport, Bob A; Resnick, Malca; Strand, Vibeke; Vanhove, Geertrui F; Veasley, Christin; Versavel, Mark; Wasan, Ajay D; Turk, Dennis C; Dworkin, Robert H
Clinical trial participants often require additional instruction to prevent idiosyncratic interpretations regarding completion of patient-reported outcomes. The Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks (ACTTION) public-private partnership developed a training system with specific, standardized guidance regarding daily average pain intensity ratings. A 3-week exploratory study among participants with low-back pain, osteoarthritis of the knee or hip, and painful diabetic peripheral neuropathy was conducted, randomly assigning participants to 1 of 3 groups: training with human pain assessment (T+); training with automated pain assessment (T); or no training with automated pain assessment (C). Although most measures of validity and reliability did not reveal significant differences between groups, some benefit was observed in discriminant validity, amount of missing data, and ranking order of least, worst, and average pain intensity ratings for participants in Group T+ compared with the other groups. Prediction of greater reliability in average pain intensity ratings in Group T+ compared with the other groups was not supported, which might indicate that training produces ratings that reflect the reality of temporal pain fluctuations. Results of this novel study suggest the need to test the training system in a prospective analgesic treatment trial.
Case Study: The Use of Massage Therapy to Relieve Chronic Low-Back Pain
Allen, Laura
Objectives To study the effects of massage on chronic low-back pain in a patient with four different diagnoses: osteoarthritis, scoliosis, spinal stenosis, and degenerative disc disease. The patient's goal was to cut down on the amount of pain medication he takes. Methods A 63-year-old man with chronic back pain received four massages across a twenty-day period. Progress was recorded using the Oswestry Low Back Pain Scale, as he self-reported on levels of pain and interference with his activities of daily living. Results Improvement was noted in 9 out of 10 measurements of self-reported pain and activities of daily living, with the only exception being his ability to lift heavy objects, which remained unchanged. The most dramatic differences were improvements in his ability to walk, and in the changing degrees of pain. The client also self-reported being able to decrease his pain medication and the ability to ride his bicycle for the first time in years. Conclusions Massage therapy is a promising treatment for chronic low-back pain for patients who may have multiple pathologies, any one of which could be responsible for the condition. Further study is encouraged to determine the efficacy of massage therapy as a readily accessible, lower-cost alternative to more invasive therapies and as an adjunct to regular medical care, when appropriate. PMID:27648110
Risk factors for neck pain in office workers: a prospective study
Hush, Julia M; Maher, Chris G; Refshauge, Kathryn M
Background Persisting neck pain is common in society. It has been reported that the prevalence of neck pain in office workers is much higher than in the general population. The costs to the worker, employer and society associated with work-related neck pain are known to be considerable and are escalating. The factors that place office workers at greater risk of developing neck pain are not understood. The aim of this study is to investigate the incidence and risk factors of work-related neck pain in Australian office workers. Methods/design We will conduct a prospective cohort study. A cohort of office workers without neck pain will be followed over a 12 month period, after baseline measurement of potential risk factors. The categories of risk factors being evaluated are physical (cervical spine posture, range of movement, muscle endurance and exercise frequency), demographic (age, sex), work environment (sitting duration, frequency of breaks) and psychosocial (psychological distress and psychosocial work factors). Cox regression analysis will be used to identify risk factors associated with work-related neck pain, and will be expressed as hazard ratios with 95% confidence intervals. The data will also enable the incidence of neck pain in this population to be estimated. Discussion In addition to clarifying the magnitude of this occupational health problem these data could inform policy in workplaces and provide the basis for primary prevention of neck pain in office workers, targeting the identified risk factors. PMID:17062165
Peer volunteers in an integrative pain management program for frail older adults with chronic pain: study protocol for a randomized controlled trial
Background Chronic pain is common among the older population. A literature review on pain management program showed that exercise, yoga, massage therapy, Tai Chi, and music therapy could significantly reduce pain. In spite of the proven benefits of pain management programs, these intervention programs were effective only in the short term, and older adults would resume their old habits. It has been suggested that interventions comprising some type of social support have great potential to increase the participation of older adults. Therefore, we propose the inclusion of peer volunteers in an integrated pain management program to relieve pain among frail older adults. This study aims to explore the effectiveness of an integrated pain management program supplemented with peer volunteers in improving pain intensity, functional mobility, physical activity, loneliness levels, happiness levels, and the use of non-pharmacological pain-relieving methods among frail older adults with chronic pain. Methods/Design We intend to recruit 30 nursing home residents and 30 peer volunteers from the Institute of Active Ageing in Hong Kong in a group trial for an 8-week group-based integrated pain management program. There will be 16 sessions, with two 1-hour sessions each week. The primary outcome will be pain levels, while secondary outcomes will be assessed according to functional mobility, physical activity, loneliness levels, happiness levels, the use of non-pharmacological pain-relieving methods, and through a questionnaire for volunteers. Discussion In view of the high prevalence of chronic pain among older adults and its adverse impacts, it is important to provide older adults with tools to control their pain. We propose the use of peer volunteers to enhance the effects of an integrated pain management program. It is expected that pain can be reduced and improvements can be achieved among older adults in the areas of physical activity, functional mobility, loneliness levels
Neuropathic pain in the general population: a systematic review of epidemiological studies.
van Hecke, O; Austin, Sophie K; Khan, Rafi A; Smith, B H; Torrance, N
Most patients with neuropathic pain symptoms present and are managed in primary care, with only a minority being referred for specialist clinical assessment and diagnoses. Previous reviews have focused mainly on specific neuropathic pain conditions based in specialist settings. This is the first systematic review of epidemiological studies of neuropathic pain in the general population. Electronic databases were searched from January 1966 to December 2012, and studies were included where the main focus was on neuropathic pain prevalence and/or incidence, either as part of a specific neuropathic pain-related condition or as a global entity in the general population. We excluded studies in which data were extracted from pain or other specialist clinics or focusing on specific population subgroups. Twenty-one articles were identified and underwent quality assessment and data extraction. Included studies differed in 3 main ways: method of data retrieval, case ascertainment tool used, and presentation of prevalence/incidence rates. This heterogeneity precluded any meta-analysis. We categorised comparable incidence and prevalence rates into 2 main subgroups: (1) chronic pain with neuropathic characteristics (range 3-17%), and (2) neuropathic pain associated with a specific condition, including postherpetic neuralgia (3.9-42.0/100,000 person-years [PY]), trigeminal neuralgia (12.6-28.9/100,000 PY), painful diabetic peripheral neuropathy (15.3-72.3/100,000 PY), glossopharyngeal neuralgia (0.2-0.4/100,000 PY). These differences highlight the importance of a standardised approach for identifying neuropathic pain in future epidemiological studies. A best estimate of population prevalence of pain with neuropathic characteristics is likely to lie between 6.9% and 10%.
Pain Management in Cancer Patients Using a Mobile App: Study Design of a Randomized Controlled Trial
Kamdar, Mihir; Flanagan, Clare; Searl, Meghan; Traeger, Lara; Kvedar, Joseph; Jethwani, Kamal
Background Despite the availability of effective medications and clinical guidelines for pain management, pain control is suboptimal in a sizeable proportion of patients with cancer pain. The National Comprehensive Cancer Network guidelines recommend a comprehensive and multimodal approach for management of cancer pain. We developed a mobile phone application, ePAL, based on clinical guidelines to empower patients for cancer pain management by prompting regular pain assessments and coaching for self-management. Objective The objective of this study is to evaluate the effect of a multidimensional mobile phone-based pain management application, ePAL, on controlling cancer pain and improving quality of life in patients with cancer pain being treated at an academic palliative care clinic. Methods The study will be implemented as a 2-arm randomized controlled trial with 110 adult patients with CP who own a mobile phone over a follow-up period of two months. Participants will be randomized to either the intervention group receiving ePAL and usual care or to a control group receiving only usual care. The brief pain inventory will be used to assess our primary outcome which is pain intensity. We will also evaluate the effect of the intervention on secondary outcomes which include the effect of the intervention on hospital utilization for pain crisis, quality of life, adherence to analgesic medications, barriers to pain control, anxiety and patient engagement. Instruments that will be used in evaluating secondary outcomes include the Brief Pain Inventory, Morisky Medication Adherence Scale, Barriers Questionnaire-II, Functional Assessment of Cancer Therapy–General, Edmonton Symptom Assessment System, Generalized Anxiety Disorder 7-item scale, and the Functional Assessment of Chronic Illness Therapy-Fatigue. The intention-to-treat approach will be used to evaluate outcomes. Our primary outcome, pain intensity, measured longitudinally over eight weeks, will be assessed by
A Prevalence and Management Study of Acute Pain in Children Attending Emergency Departments by Ambulance.
Murphy, Adrian; McCoy, Siobhan; O'Reilly, Kay; Fogarty, Eoin; Dietz, Jason; Crispino, Gloria; Wakai, Abel; O'Sullivan, Ronan
Pain is the most common symptom in the emergency setting and remains one of the most challenging problems for emergency care providers, particularly in the pediatric population. The primary objective of this study was to determine the prevalence of acute pain in children attending emergency departments (EDs) in Ireland by ambulance. In addition, this study sought to describe the prehospital and initial ED management of pain in this population, with specific reference to etiology of pain, frequency of pain assessment, pain severity, and pharmacological analgesic interventions. A prospective cross-sectional study was undertaken over a 12-month period of all pediatric patients transported by emergency ambulance to four tertiary referral hospitals in Ireland. All children (<16 years) who had pain as a symptom (regardless of cause) at any stage during the prehospital phase of care were included in this study. Over the study period, 6,371 children attended the four EDs by emergency ambulance, of which 2,635 (41.4%, 95% confidence interval 40.2-42.3%) had pain as a documented symptom on the ambulance patient care report (PCR) form. Overall 32% (n = 856) of children who complained of pain were subject to a formal pain assessment during the prehospital phase of care. Younger age, short transfer time to the ED, and emergency calls between midnight and 6 am were independently associated with decreased likelihood of having a documented assessment of pain intensity during the prehospital phase of care. Of the 2,635 children who had documented pain on the ambulance PCR, 26% (n = 689) received some form of analgesic agent prior to ED arrival. Upon ED arrival 54% (n = 1,422) of children had a documented pain assessment and some form of analgesic agent was administered to 50% (n = 1,324). Approximately 41% of children who attend EDs in Ireland by ambulance have pain documented as their primary symptom. This study suggests that the management of acute pain in children transferred by
An Experimental Study of Thrust Augmenting Ejectors
A , AN EXPERIMENTAL STUDY OF THRUST AUG'XENTING EJECTORS THESIS William D. Lewis Captain 11. S. Army AFIT/GAE/Ai/83D- 13 1 DTIC Li~i ELECTE JANI...83D-13 AN LEPERIMENTAL STUDY OF THRUST AUG-M..TING EJECTORS "l•HSIS William D. Levis Captain U. S. Army AF1T/GAAE/AA/$3D- 13 'jK Approved for public...release; distribution unliaited I V .,, AFIT/GAE/AA/83D- 13 AN EXPERIMENTAL STUDY OF THRUST AUGMENTING EJECTORS THESIS Presented to *he Faculty of the
Pilot study: rapidly cycling hypobaric pressure improves pain after 5 days in adiposis dolorosa
Herbst, Karen L; Rutledge, Thomas
Adiposis dolorosa (AD) is a rare disorder of painful nodular subcutaneous fat accompanied by fatigue, difficulty with weight loss, inflammation, increased fluid in adipose tissue (lipedema and lymphedema), and hyperalgesia. Sequential compression relieves lymphedema pain; we therefore hypothesized that whole body cyclic pneumatic hypobaric compression may relieve pain in AD. To avoid exacerbating hyperalgesia, we utilized a touch-free method, which is delivered via a high-performance altitude simulator, the Cyclic Variations in Altitude Conditioning™ (CVAC™) process. As a pilot study, 10 participants with AD completed pain and quality of life questionnaires before and after 20–40 minutes of CVAC process daily for 5 days. Participants lost weight (195.5 ± 17.6–193.8 ± 17.3 lb; P = 0.03), and bioimpedance significantly decreased (510 ± 36–490 ± 38 ohm; P = 0.01). There was a significant decrease in scores on the Pain Catastrophizing Scale (P = 0.039), in average (P = 0.002), highest (P = 0.029), lowest (P = 0.04), and current pain severity (P = 0.02) on the Visual Analogue Scale, but there was no change in pain quality by the McGill Pain Questionnaire. There were no significant changes in total and physical SF-36 scores, but the mental score improved significantly (P = 0.049). There were no changes in the Pain Disability Index or Pittsburgh Sleep Quality Index. These data present a potential, new, noninvasive means of treating pain in AD by whole body pneumatic compression as part of the CVAC process. Although randomized, controlled trials are needed to confirm these data, the CVAC process could potentially help in treating AD pain and other chronic pain disorders. PMID:21197318
Long-Term Outcome of the Management of Chronic Neuropathic Pain: A Prospective Observational Study.
Moulin, Dwight E; Clark, A John; Gordon, Allan; Lynch, Mary; Morley-Forster, Patricia K; Nathan, Howard; Smyth, Cathy; Toth, Cory; VanDenKerkhof, Elizabeth; Gilani, Ammar; Ware, Mark A
This prospective observational cohort study addressed the long-term clinical effectiveness of the management of chronic neuropathic noncancer pain at 7 Canadian tertiary pain centers. Patients were treated according to standard guidelines and were followed at 3, 6, 12, 18, and 24 months. Standard outcome measures for pain, mood, quality of life, and overall treatment satisfaction were administered, with the primary outcome measure designated as the composite of 30% reduction in average pain intensity and 1-point decrease in the mean Interference Scale Score (0-10) of the Brief Pain Inventory at 12 months relative to baseline. Of 789 patients recruited, mean age was 53.5 ± 14.2 years (55% female) and mean duration of pain was 4.88 ± 5.82 years. Mean average pain intensity (0-10) at baseline was 6.1 ± 1.9. All standard outcome measures showed statistically significant improvement at 12 months relative to baseline (P < .001). However, only 23.7% attained clinically significant improvement in pain and function at 12 months as the primary outcome measure. Univariable analyses showed poorer outcomes at 12-month follow-up with longer duration of pain (P = .002), greater cigarette use (P = .01), more disability compensation (P = .001), and higher opioid doses at baseline and at 12 months (P < .02). Our present treatment modalities provide significant long-term benefit in only about a quarter of patients with neuropathic pain managed at tertiary care pain clinics. Opioid therapy may not be beneficial for the long term. Perspective: Evidence-based treatment of chronic neuropathic pain provides long-term benefit in only about one-quarter of patients seen in tertiary care centers. Opioid therapy may not be beneficial.
Patient Satisfaction with Spanish Pain Centers: Observational Study with More than 3,000 Patients
Hernández-Puiggròs, Patricia; Tesedo Nieto, Javier; Acín Lázaro, María Pilar; Carrera González, Alfredo; Soler, Miguel José Arranz; Maldonado Vega, Sergio
Chronic pain is a serious problem in Spain. This multicenter, epidemiological 3-month follow-up study investigates pain management efficacy in Spanish centers using patient satisfaction criteria. 3,414 eligible adult patients (65,6% female) with moderate to severe chronic pain from 146 pain centers were included. Patient satisfaction was assessed based onto question 18 of Spanish healthcare barometer-CSI. Pain evolution (Brief Pain Inventory-Short Form (BPI-SF) and visual analog scale (VAS)), quality of life/EuroQol-5, and pain control expectations fulfillment were also assessed. Mean age was 61.3 years. 64.4% of participating centers employed multidisciplinary pain management approach. After 3 months, mean patient satisfaction was 7.8 (1–10) on the CIS barometer. Medical staff received the highest scores, whereas waiting for tests, appointment request to appointment date time, and waiting times at the center the lowest. Mean pain decreased from 7.4 to 4.0; BPI-SF intensity decreased from 6.5 to 3.8; pain control expectations were met in 78.7% of patients; EuroQoL-5D utility index increased from 0.37 to 0.62, p < 0.001, and health status (VAS) from 40.6 to 61.9, p < 0.001. Chronic pain patients (90%) are satisfied with Spanish centers care; 80% had their pain control expectations met. Quality of life improved remarkably: 71% felt moderately to significantly better. However, waiting times need improvement. PMID:27516902
The effect of repeated intramuscular alfentanil injections on experimental pain and abuse liability indices in healthy males
Tompkins, D. Andrew; Smith, Michael T.; Bigelow, George E.; Moaddel, Ruin; Venkata, S.L. Vatem; Strain, Eric C.
Objective Opioid-induced hyperalgesia (OIH), increased sensitivity to noxious stimuli following repeated opioid exposures, has been demonstrated in pre-clinical studies. However, there is no accepted, prospective model of OIH following repeated opioid exposures currently available in humans. This study assessed a potential prospective OIH model. Methods Double-blind intramuscular (IM) injections of a short-acting opioid, (alfentanil 15 mcg/kg; N=8) were compared to active placebo (diphenhydramine 25 mg; N=3) on cold and pressure pain testing and standard abuse liability measures in eight 10-hour sessions (1 injection/session) over 4–5 weeks in healthy pain-free males. Decreases from session baseline pain threshold (PThr) and tolerance (PTol) were calculated to represent hyperalgesia, and were assessed both within and across sessions. Results Mean decreases in cold PTol were seen in the alfentanil group at 180 minutes (−3.8 seconds, +/−26.5) and 480 minutes (−1.63 seconds, +/−31.5) after drug administration. There was a trend for differences between conditions on cold PThr hyperalgesia but not for pressure PThr. Alfentanil participants had greater mean ratings on LIKING and HIGH visual analog scales at peak effects (30 minutes), but these scores did not change across sessions. Discussion Repeated alfentanil exposures over 4–5 weeks resulted in within session decreases in cold pain tolerance from baseline but these differences were not substantially different from diphenhydramine controls. The results did not support the phenomenon of OIH in this model, although definitive conclusions regarding the existence of OIH in humans likely requires a larger sample size or an alternative model. PMID:23446076
Pain modulation by intranasal oxytocin and emotional picture viewing — a randomized double-blind fMRI study
Zunhammer, Matthias; Geis, Sandra; Busch, Volker; Eichhammer, Peter; Greenlee, Mark W.
The hormone oxytocin has been hypothesized to influence the emotional dimension of pain. This randomized, placebo-controlled, double-blind, crossover study explored whether intranasal oxytocin and emotional context can affect heat pain perception in 30 healthy male volunteers. After receiving 36 IU oxytocin or placebo, participants underwent functional Magnetic Resonance Imaging (fMRI) during which noxious and non-noxious thermode heat stimuli were applied. Simultaneously, scenes from the International Affective Pictures System (IAPS) with positive, neutral, and negative emotional valence were shown. Heat intensity and unpleasantness ratings were obtained. The activity of whole-brain correlates of heat processing was quantified via multi-voxel pattern analysis. We observed no appreciable main effects of oxytocin on ratings or neural pain correlates. Effects of emotional picture valence on ratings were smaller than reported in previous studies. Nevertheless, oxytocin was found to significantly enhance the influence of picture valence on unpleasantness ratings at noxious heat levels. No corresponding changes in whole-brain correlates of heat intensity processing were found. Our study provides evidence that intranasal oxytocin increases the effects of emotional context on the subjective unpleasantness of experimental heat pain. Future studies are needed to determine whether this effect can be utilized in clinical settings. PMID:27546446
Selective small molecule angiotensin II type 2 receptor antagonists for neuropathic pain: preclinical and clinical studies.
Smith, Maree T; Anand, Praveen; Rice, Andrew S C
Neuropathic pain affects up to 10% of the general population, but drug treatments recommended for the treatment of neuropathic pain are associated with modest efficacy and/or produce dose-limiting side effects. Hence, neuropathic pain is an unmet medical need. In the past 2 decades, research on the pathobiology of neuropathic pain has revealed many novel pain targets for use in analgesic drug discovery programs. However, these efforts have been largely unsuccessful as molecules that showed promising pain relief in rodent models of neuropathic pain generally failed to produce analgesia in early phase clinical trials in patients with neuropathic pain. One notable exception is the angiotensin II type 2 (AT2) receptor that has clinical validity on the basis of a successful double-blind, randomized, placebo-controlled, clinical trial of EMA401, a highly selective, orally active, peripherally restricted AT2 receptor antagonist in patients with postherpetic neuralgia. In this study, we review research to date on target validation, efficacy, and mode of action of small molecule AT2 receptor antagonists in rodent models of peripheral neuropathic pain and in cultured human sensory neurons, the preclinical pharmacokinetics of these compounds, and the outcome of the above clinical trial.
Breast size, bra fit and thoracic pain in young women: a correlational study
Wood, Katherine; Cameron, Melainie; Fitzgerald, Kylie
Introduction A single sample study was undertaken to determine the strength and direction of correlations between: a) breast size and thoracic spine or posterior chest wall pain; b) bra fit and thoracic spine or posterior chest wall pain and; c) breast size and bra fit, in thirty nulliparous women (18–26 years), with thoracic spine or posterior chest wall pain, who wore bras during daytime. Measures Pain (Short Form McGill Pain Questionnaire), bra size (Triumph International), bra fit (Triumph International). Results Most (80%) women wore incorrectly sized bras: 70% wore bras that were too small, 10% wore bras that were too large. Breast size was negatively correlated with both bra size (r = -0.78) and bra fit (r = -0.50). These results together indicate that large breasted women were particularly likely to be wearing incorrectly sized and fitted bras. Negligible relationships were found between pain and bra fit, and breast size and pain. Menstrual cycle stage was moderately positively correlated with bra fit (r = 0.32). Conclusion In young, nulliparous women, thoracic pain appears unrelated to breast size. Bra fit is moderately related to stage of menstrual cycle suggesting that this research may be somewhat confounded by hormonal changes or reproductive stage. Further research is needed to clarify whether there is a relationship between breast size or bra fit and thoracic pain in women during times of hormonal change. PMID:18339205
Diagnosis and Characters of Non-Specific Low Back Pain in Japan: The Yamaguchi Low Back Pain Study
Suzuki, Hidenori; Kanchiku, Tsukasa; Imajo, Yasuaki; Yoshida, Yuichiro; Nishida, Norihiro; Taguchi, Toshihiko
Study Design Cross sectional data from the Yamaguchi low back pain study conducted in Yamaguchi prefecture, Japan, was used for this analysis. Methods A total of 320 patients were recruited from walk-in orthopedic clinics in Yamaguchi Prefecture, Japan. Patients visited the clinics primarily for low back pain (LBP) and sought treatment between April and May 2015. A self-questionnaire was completed by patients, while radiographic testing and neurological and physical examination was performed by the orthopedist in each hospital. The cause and characters of LBP was determined following examination of the data, regional anesthesia and block injection. Results 'Specific LBP' was diagnosed in 250 (78%) patients and non-diagnosable, 'non-specific LBP' in 70 (22%) patients. The VAS scores of patients were: LBP, 5.8±0.18; leg pain, 2.9±0.18 and the intensity of leg numbness was 1.9±0.16. Item scores for SF-8 were: general health, 46.6±0.40; physical function, 43.5±0.51; physical limitations, 42.8±0.53; body pain, 42.1±0.52; vitality, 48.4±0.37; social function, 46.9±0.53; emotional problems, 48.9±0.43; mental health, 46.9±0.43. Conclusions The incidence of non-specific LBP in Japan was lower than previous reports from western countries, presumably because of variation in the diagnosis of LBP between different health care systems. In Japan, 78% of cases were classified as 'specific LBP' by orthopedists. Identification of the definitive cause of LBP should help to improve the quality of LBP treatment. PMID:27548658
An Action Research Study Exploring How Education May Enhance Pain Management in Children.
ERIC Educational Resources Information Center
Simons, Joan M.
Focus groups (n=14) and a study day (n=10) on pain management for child patients were held for pediatric nurses. Participants felt they increased their knowledge of pharmacology and their confidence and assertiveness in the practice of pain management. (Contains 37 references.) (SK)
Being in Pain: A Phenomenological Study of Young People with Cerebral Palsy
ERIC Educational Resources Information Center
Castle, Kirstyn; Imms, Christine; Howie, Linsey
This study explored the experience and impact of chronic pain on the lives of adolescents and young adults with cerebral palsy (CP). Six participants with CP (four males, two females; age range 14-24y) who were known to experience chronic pain participated in individual in-depth interviews. Five participants had quadriplegia and used wheelchairs;…
Effects of analgesia of the distal interphalangeal joint and navicular bursa on experimental lameness caused by solar pain in horses.
Sardari, K; Kazemi, H; Mohri, M
It has been hypothesized that pain originating from the dorsal margin of the sole of the hoof in horses can be attenuated by analgesia of either the distal interphalangeal (DIP) joint, or of the navicular bursa (NB). To test this hypothesis, an experimental lameness was induced in the toe region of the left forelimb in six adult horses. After this, both synovial structures were blocked and the effects on the lameness were semi-quantitatively scored. Lameness was induced by creating pressure on the dorsal margin of the sole with the help of set-screws that were screwed into a nut, welded to the inside of each branch of the shoe. Gaits were recorded on a videotape before and after application of the screws, and after application of either a local anaesthetic or saline into the DIP joint or NB. The gaits were independently evaluated by two blinded clinicians and scored. Lameness scores were high after application of the screws and remained high after the administration of saline, but decreased significantly (P < 0.05) after administration of the local anaesthetic. Analgesia of the DIP joint as well as the NB appeared to be able to desensitize a portion of the sole. It was concluded that pain arising from the toe region of the sole should not be excluded as a cause of lameness when lameness is attenuated by analgesia of the DIP joint, or of the NB.
Inter-Hospital Variability of Postoperative Pain after Tonsillectomy: Prospective Registry-Based Multicentre Cohort Study
Guntinas-Lichius, Orlando; Geißler, Katharina; Komann, Marcus; Schlattmann, Peter; Meissner, Winfried
Objectives Although tonsillectomy is one of the most frequent and painful surgeries, the association between baseline and process parameters and postoperative pain are not fully understood. Methods A multicentre prospective cohort study using a web-based registry enrolled 1,527 women and 1,008 men aged 4 to 85 years from 52 German hospitals between 2006 and 2015. Maximal pain (MP) score the first day after surgery on a numeric rating scale (NRS) from 0 (no pain) to 10 (MP) was the main outcome parameter. Results The mean maximal pain score was 5.8±2.2 (median 6). Multivariable analysis revealed that female gender (Odds ratio [OR] = 1.33; 95% confidence interval [CI] = 1.12 to 1.56; p = 0.001), age <20 years (OR = 1.56; CI = 1.27 to 1.91; p<0.0001), no pain counselling (OR = 1.78; CI = 1.370 to 2.316; p<0.001), chronic pain (OR = 1.34; CI = 1.107 to 1.64; p = 0.004), and receiving opioids in recovery room (OR = 1.89; CI = 1.55 to 2.325; p<0.001) or on ward (OR = 1.79; CI = 1.42 to 2.27; p<0.001) were independently associated with higher experienced maximal postoperative pain (greater the median of 6). The effect of age on pain was not linear. Maximal pain increased in underage patients to a peak at the age of 18 to 20 years. From the age of ≥20 years on, maximal pain after tonsillectomy continuously decreased. Even after adjustment to all statistically important baseline and process parameters, there was substantial variability of maximal pain between hospitals with a heterogeneity variance of 0.31. Conclusion Many patients seem to receive insufficient or ineffective analgesia after tonsillectomy. Further research should address if populations at risk of higher postoperative pain such as females, younger patients or those with preexisting pain might profit from a special pain management protocol. Beyond classical demographical and process parameters the large variability between different hospitals is striking and indicates the existence of other unknown factors
Experimental and Modeling Studies of Massif Anorthosites
NASA Technical Reports Server (NTRS)
Longhi, John
This termination report covers the latter part of a single research effort spanning several grant cycles. During this time there was a single title, "Experimental and Modeling Studies of Massif Anorthosites", but there were several contract numbers as the mode and location of NASA contract administration changed. Initially, the project was funded as an increment to the PI's other grant, "Early Differentiation of the Moon: Experimental and Modeling Studies", but subsequently it became an independent grant. Table 1 contains a brief summary of the dates and contract numbers.
Spinal cord stimulation for predominant low back pain in failed back surgery syndrome: study protocol for an international multicenter randomized controlled trial (PROMISE study)
Background Although results of case series support the use of spinal cord stimulation in failed back surgery syndrome patients with predominant low back pain, no confirmatory randomized controlled trial has been undertaken in this patient group to date. PROMISE is a multicenter, prospective, randomized, open-label, parallel-group study designed to compare the clinical effectiveness of spinal cord stimulation plus optimal medical management with optimal medical management alone in patients with failed back surgery syndrome and predominant low back pain. Method/Design Patients will be recruited in approximately 30 centers across Canada, Europe, and the United States. Eligible patients with low back pain exceeding leg pain and an average Numeric Pain Rating Scale score ≥5 for low back pain will be randomized 1:1 to spinal cord stimulation plus optimal medical management or to optimal medical management alone. The investigators will tailor individual optimal medical management treatment plans to their patients. Excluded from study treatments are intrathecal drug delivery, peripheral nerve stimulation, back surgery related to the original back pain complaint, and experimental therapies. Patients randomized to the spinal cord stimulation group will undergo trial stimulation, and if they achieve adequate low back pain relief a neurostimulation system using the Specify® 5-6-5 multi-column lead (Medtronic Inc., Minneapolis, MN, USA) will be implanted to capture low back pain preferentially in these patients. Outcome assessment will occur at baseline (pre-randomization) and at 1, 3, 6, 9, 12, 18, and 24 months post randomization. After the 6-month visit, patients can change treatment to that received by the other randomized group. The primary outcome is the proportion of patients with ≥50% reduction in low back pain at the 6-month visit. Additional outcomes include changes in low back and leg pain, functional disability, health-related quality of life, return to work
Much Pain, Little Gain? Paradigm-Specific Models and Methods in Experimental Psychology.
Meiser, Thorsten
Paradigm-oriented research strategies in experimental psychology have strengths and limitations. On the one hand, experimental paradigms play a crucial epistemic and heuristic role in basic psychological research. On the other hand, empirical research is often limited to the observed effects in a certain paradigm, and theoretical models are frequently tied to the particular features of the given paradigm. A paradigm-driven research strategy therefore jeopardizes the pursuit of research questions and theoretical models that go beyond a specific paradigm. As one example of a more integrative approach, recent research on illusory and spurious correlations has attempted to overcome the limitations of paradigm-specific models in the context of biased contingency perception and social stereotyping. Last but not least, the use of statistical models for the analysis of elementary cognitive functions is a means toward a more integrative terminology and theoretical perspective across different experimental paradigms and research domains.
A Study on Factors Affecting Low Back Pain and Safety and Efficacy of NSAIDs in Acute Low Back Pain in a Tertiary Care Hospital of Western Nepal
Bhattarai, Srijana; Chhetri, Himal Paudel; Alam, Kadir; Thapa, Pabin
Introduction: Low back pain is characterized by a range of symptoms which include pain, muscle tension or stiffness, and is localized between the shoulder blades and the folds of the buttocks, with or without spreading to the legs. Non-Steroidal Anti Inflammatory Drugs (NSAIDs) are the drugs of choice which provide an analgesic effect for acute low back pain. Aim: To study the factors affecting low back pain, efficacy and safety of different non-steroidal anti-inflammatory drugs (aceclofenac, diclofenac, naproxen and nimesulide) in low back pain. Methodology: Data collection form and numeric pain rating scale were used as study tools for studying patients' demographies and severities of pain respectively. Patients prescribed with aceclofenac 100 mg , diclofenac 100 mg, naproxen 500 mg and nimesulide 100 mg for acute low back pain at Orthopaedics Outpatients Department of Manipal Teaching Hospital, Nepal, were enrolled in this study. The decrease in pain scores was recorded on 5th and 10th days of follow-up and pain scores were calculated. Descriptive statistics and Kruskal Wallis non parametric test were used for analysis. Results: Among 150 patients, 67.3% were females (n=101). Low back pain was more prevalent (24.7%) in age-group of 59-68 years and a positive correlation was seen. Similarly, low back pain was found to be high among people involved in agriculture, heavy weight lifters and non smokers. The decrease in average pain scores was more in the patients treated with aceclofenac (4.83 ± 0.537), followed by that in those who were treated with naproxen (4.13 ± 0.067) and diclofenac (3.84 ± 0.086). The decrease in pain scores was found to be lowest among patients who were treated with nimesulide (2.11 ± 0.148). Nimesulide presented more number of side-effects than the comparative drugs. Conclusion: Different factors affect low back pain, such as age, gender, personal habit, posture, occupation, weight lifting. Aceclofenac showed greater decrease in pain
Craniofacial pain can be the sole prodromal symptom of an acute myocardial infarction: an interdisciplinary study.
Kreiner, Marcelo; Álvarez, Ramón; Michelis, Virginia; Waldenström, Anders; Isberg, Annika
We recently found craniofacial pain to be the sole symptom of an acute myocardial infarction (AMI) in 4% of patients. We hypothesized that this scenario is also true for symptoms of prodromal (pre-infarction) angina. We studied 326 consecutive patients who experienced myocardial ischemia. Intra-individual variability analyses with respect to ECG findings and pain characteristics were performed for those 150 patients who experienced at least one recurrent ischemic episode. AMI patients (n=113) were categorized into two subgroups: "abrupt onset" (n=81) and "prodromal angina" (n=32). Age, gender and risk factor comparisons were performed between groups. Craniofacial pain constituted the sole prodromal symptom of an AMI in 5% of patients. In those who experienced two ischemic episodes, women were more likely than men to experience craniofacial pain in both episodes (p<0.01). There was no statistically significant difference between episodes regarding either ECG findings or the use of the two typical pain quality descriptors "pressure" and "burning". This study is to our knowledge the first to report that craniofacial pain can be the only symptom of a pre-infarction angina. Craniofacial pain constitutes the sole prodromal AMI symptom in one out of 20 AMI patients. Recognition of this atypical symptom presentation is low because research on prodromal AMI symptoms has to date studied only patients with chest pain. To avoid a potentially fatal misdiagnosis, awareness of this clinical presentation needs to be brought to the attention of clinicians, researchers and the general public.
Lumbar facet injection for the treatment of chronic piriformis myofascial pain syndrome: 52 case studies
Huang, Jen-Ting; Chen, Han-Yu; Hong, Chang-Zern; Lin, Ming-Ta; Chou, Li-Wei; Chen, Hsin-Shui; Tsai, Chien-Tsung; Chang, Wen-Dien
Background and aims The aim of this study was to demonstrate the effectiveness of lumbar facet joint injection for piriformis myofascial pain syndrome. Methods Fifty-two patients with chronic myofascial pain in the piriformis muscle each received a lumbar facet injection into the ipsilateral L5–S1 facet joint region, using the multiple insertion technique. Subjective pain intensity, trunk extension range, and lumbar facet signs were measured before, immediately after, and 2 weeks after injection. Thirty-six patients received follow-up for 6 months. Results Immediately after the injection, 27 patients (51.9%) had complete pain subsidence, 19 patients (36.5%) had pain reduction to a tolerable level, and only 6 patients (11.5%) had no pain relief to a tolerable level. Mean pain intensity was reduced from 7.4±0.9 to 1.6±2.1 after injection (P<0.01). This effectiveness lasted for 2 weeks in 49 patients (94.2%), and lasted for approximately 6 months in 35 (97.2%) of 36 patients. The mean range of motion increased from 13.4±6.8 degrees to 22.1±6.0 degrees immediately after injection, and further increased 2 weeks and 6 months later. Immediately after injection, 45 patients (86.5%) had no facet sign. In addition, 90.4% and 94.4% of patients had no facet sign after 2 weeks and after 6 months, respectively. Conclusions It is important to identify the possible cause of piriformis myofascial pain syndrome. If this pain is related to lumbar facet lesions, lumbar facet joint injection can immediately suppress piriformis myofascial pain symptoms. This effectiveness may last for at least 6 months in most patients. This study further supports the importance of eliminating the underlying etiological lesion for complete and effective relief of myofascial pain syndrome. PMID:25170256
Peer mentorship teaches social tools for pain self-management: A case study
Goldenberg, David; Payne, Laura A; Hayes, Loran P; Zeltzer, Lonnie K; Tsao, Jennie CI
Pain in children can become chronic and disabling, associated with high degrees of social isolation from schooling absences, physical limitations that prevent participation in social settings, and difficulties forming self-identity. This lack of social support network impairs social coping skills and can lead to worsening pain symptoms. Objective In this case study, we describe a new program to disrupt the cycle of social isolation and chronic pain by emphasizing social coping skills via peer mentorship. The program aimed to utilize peers who have learned to self-manage their own chronic pain to assist patients with social coping skills to reduce isolation caused by chronic pain conditions. Study Group Children and adolescents with chronic pain. Methods This case describes the experience of a 17 year-old, African American boy with diffuse chronic body pain as a participant ("the mentee") in the program; his mentor was a 19 year-old girl with chronic pain associated with rheumatoid arthritis. The mentor received six hours of training and she mentored the patient in 10 weekly sessions. Results The mentee connected very well with his mentor through sharing similar pain experiences. He demonstrated improvements in positive affect, sleep, social coping, and perception of bodily pain on a variety of quantitative measures. Qualitative data from interviews also suggested that the mentee learned important social coping skills through peer mentorship. Conclusions A peer mentoring approach to chronic pain may help alleviate social isolation in adolescents and result in improvements in a number of associated symptoms. PMID:25383136
Patients' Perception of Chronic-Pain-Related Patient-Provider Communication in Relation to Sociodemographic and Pain-Related Variables: A Cross-Sectional Nationwide Study.
Jonsdottir, Thorbjorg; Gunnarsdottir, Sigridur; Oskarsson, Gudmundur K; Jonsdottir, Helga
Pain is a personal experience and patient-provider communication therefore an essential part of diagnosis and treatment where the patient's perspective needs to be central. The aim of this descriptive cross-sectional study was to investigate chronic-pain-related patient-provider communication in the context of sociodemographic variables, pain variables, perceived outcome of care, and satisfaction with health care providers. A postal questionnaire measuring socio-demographic variables, pain characteristics, pain-related health care utilization and patient-provider communication was sent to a sample of 4,500 individuals randomly drawn from the national population of Iceland. A subsample reporting chronic pain and having visited a health care provider for pain the previous six months (n = 401) was analyzed. Relationships between patient-provider communication and other measured variables were tested using bivariate and multivariate statistics. The more chronic pain impaired health-related quality of life, the more provider control the patients perceived in the patient-provider communication. There was also a strong negative relationship between patients' perception of providers' support and openness to discussing symptoms, and satisfaction with health care provider. Patients' perception of their own control in patient-provider communication and involvement in decisions regarding care was related to sociodemographic variables (specifically, education and residence) but not to pain related variables. This study highlights the importance of assessing chronic pain in a broad spectrum, listening, and giving patients time and support to communicate chronic pain and how it affects their life situation. The more interfering the pain is, the more important this is.
The Pain in Neuropathy Study (PiNS): a cross-sectional observational study determining the somatosensory phenotype of painful and painless diabetic neuropathy.
Themistocleous, Andreas C; Ramirez, Juan D; Shillo, Pallai R; Lees, Jonathan G; Selvarajah, Dinesh; Orengo, Christine; Tesfaye, Solomon; Rice, Andrew S C; Bennett, David L H
Disabling neuropathic pain (NeuP) is a common sequel of diabetic peripheral neuropathy (DPN). We aimed to characterise the sensory phenotype of patients with and without NeuP, assess screening tools for NeuP, and relate DPN severity to NeuP. The Pain in Neuropathy Study (PiNS) is an observational cross-sectional multicentre study. A total of 191 patients with DPN underwent neurological examination, quantitative sensory testing, nerve conduction studies, and skin biopsy for intraepidermal nerve fibre density assessment. A set of questionnaires assessed the presence of pain, pain intensity, pain distribution, and the psychological and functional impact of pain. Patients were divided according to the presence of DPN, and thereafter according to the presence and severity of NeuP. The DN4 questionnaire demonstrated excellent sensitivity (88%) and specificity (93%) in screening for NeuP. There was a positive correlation between greater neuropathy severity (r = 0.39, P < 0.01), higher HbA1c (r = 0.21, P < 0.01), and the presence (and severity) of NeuP. Diabetic peripheral neuropathy sensory phenotype is characterised by hyposensitivity to applied stimuli that was more marked in the moderate/severe NeuP group than in the mild NeuP or no NeuP groups. Brush-evoked allodynia was present in only those with NeuP (15%); the paradoxical heat sensation did not discriminate between those with (40%) and without (41.3%) NeuP. The "irritable nociceptor" subgroup could only be applied to a minority of patients (6.3%) with NeuP. This study provides a firm basis to rationalise further phenotyping of painful DPN, for instance, stratification of patients with DPN for analgesic drug trials.
The Pain in Neuropathy Study (PiNS): a cross-sectional observational study determining the somatosensory phenotype of painful and painless diabetic neuropathy
Themistocleous, Andreas C.; Ramirez, Juan D.; Shillo, Pallai R.; Lees, Jonathan G.; Selvarajah, Dinesh; Orengo, Christine; Tesfaye, Solomon; Rice, Andrew S.C.; Bennett, David L.H.
Abstract Disabling neuropathic pain (NeuP) is a common sequel of diabetic peripheral neuropathy (DPN). We aimed to characterise the sensory phenotype of patients with and without NeuP, assess screening tools for NeuP, and relate DPN severity to NeuP. The Pain in Neuropathy Study (PiNS) is an observational cross-sectional multicentre study. A total of 191 patients with DPN underwent neurological examination, quantitative sensory testing, nerve conduction studies, and skin biopsy for intraepidermal nerve fibre density assessment. A set of questionnaires assessed the presence of pain, pain intensity, pain distribution, and the psychological and functional impact of pain. Patients were divided according to the presence of DPN, and thereafter according to the presence and severity of NeuP. The DN4 questionnaire demonstrated excellent sensitivity (88%) and specificity (93%) in screening for NeuP. There was a positive correlation between greater neuropathy severity (r = 0.39, P < 0.01), higher HbA1c (r = 0.21, P < 0.01), and the presence (and severity) of NeuP. Diabetic peripheral neuropathy sensory phenotype is characterised by hyposensitivity to applied stimuli that was more marked in the moderate/severe NeuP group than in the mild NeuP or no NeuP groups. Brush-evoked allodynia was present in only those with NeuP (15%); the paradoxical heat sensation did not discriminate between those with (40%) and without (41.3%) NeuP. The "irritable nociceptor" subgroup could only be applied to a minority of patients (6.3%) with NeuP. This study provides a firm basis to rationalise further phenotyping of painful DPN, for instance, stratification of patients with DPN for analgesic drug trials. PMID:27088890
Altering gender role expectations: effects on pain tolerance, pain threshold, and pain ratings.
Robinson, Michael E; Gagnon, Christine M; Riley, Joseph L; Price, Donald D
The literature demonstrating sex differences in pain is sizable. Most explanations for these differences have focused on biologic mechanisms, and only a few studies have examined social learning. The purpose of this study was to examine the contribution of gender-role stereotypes to sex differences in pain. This study used experimental manipulation of gender-role expectations for men and women. One hundred twenty students participated in the cold pressor task. Before the pain task, participants were given 1 of 3 instructional sets: no expectation, 30-second performance expectation, or a 90-second performance expectation. Pain ratings, threshold, and tolerance were recorded. Significant sex differences in the "no expectation" condition for pain tolerance (t = 2.32, df = 38, P <.05) and post-cold pressor pain ratings (t = 2.6, df = 37, P <.05) were found. Women had briefer tolerance times and higher post-cold pressor ratings than men. When given gender-specific tolerance expectations, men and women did not differ in their pain tolerance, pain threshold, or pain ratings. This is the first empirical study to show that manipulation of expectations alters sex differences in laboratory pain.
Expanding hypnotic pain management to the affective dimension of pain.
Feldman, Jeffrey B
Experimental (Price & Barber, 1987) and neuroimaging studies (Rainville, Carrier, Hofbauer, Bushnell, & Duncan, 1999), suggest that it is the affective dimension of pain as processed in the anterior cingulate cortex (ACC) that is most associated with suffering and autonomic arousal. Conversely, pain related emotions (Rainville, Bao, & Chretien, 2005) and expectations (Koyama, McHaffie, Laurenti, & Coghill, 2005) modulate pain perception and associated pain affect. This paper presents both the scientific background and the general clinical steps involved in a practical hypnotic approach that uses emotion specific wording and the elicitation of prior positive experience to intervene at both the affective and sensory dimensions of pain. Such an approach enables patients to therapeutically use hypnosis to reduce their subjective distress even if they are not able to greatly reduce the sensation of pain. The utilization of positive state dependent learning (Rossi, 1986), following the advice of Milton Erickson to "discover their patterns of happiness" (Parsons-Fein, 2005) is emphasized.
Postoperative Pain, an Unmet Problem in Day or Overnight Italian Surgery Patients: A Prospective Study.
Campagna, Sara; Antonielli D'Oulx, Maria Delfina; Paradiso, Rosetta; Perretta, Laura; Re Viglietti, Silvia; Berchialla, Paola; Dimonte, Valerio
Background. Because of economic reasons, day surgery rates have steadily increased in many countries and the trend is to perform around 70% of all surgical procedures as day surgery. Literature shows that postoperative pain treatment remains unfulfilled in several fields such as orthopedic and general surgery patients. In Italy, the day surgery program is not yet under governmental authority and is managed regionally by local practices. Aim. To investigate the trends in pain intensity and its relation to type of surgeries and pain therapy protocols, in postoperative patients, discharged from three different Ambulatory Surgeries located in North West Italy (Piedmont region). Method. The present study enrolled 276 patients who undergone different surgical procedures in ambulatory regimen. Patients recorded postoperative pain score twice a day, compliance with prescribed drugs, and pain related reasons for contacting the hospital. Monitoring lasted for 7 days. Results. At discharge, 72% of patients were under weak opioids, 12% interrupted the treatment due to side effects, 17% of patients required extra drugs, and 15% contacted the hospital reporting pain problems. About 50% of patients experienced moderate pain during the first day after surgery. Results from our study show that most of the patients experienced avoidable pain after discharge.
Back pain prevalence and associated factors in children and adolescents: an epidemiological population study
Noll, Matias; Candotti, Cláudia Tarragô; da Rosa, Bruna Nichele; Loss, Jefferson Fagundes
ABSTRACT OBJECTIVE To identify the prevalence of back pain among Brazilian school children and the factors associated with this pain. METHODS All 1,720 schoolchildren from the fifth to the eight grade attending schools from the city of Teutonia, RS, Southern Brazil, were invited to participate in the study. From these, 1,597 children participated. We applied the Back Pain and Body Posture Evaluation Instrument. The dependent variable was back pain, while the independent one were demographic, socioeconomic, behavior and heredity data. The prevalence ratio was estimated by multivariate analysis using the Poisson regression model (α = 0.05). RESULTS The prevalence of back pain in the last three months was 55.7% (n = 802). The multivariate analysis showed that back pain is associated with the variables: sex, parents with back pain, weekly frequency of physical activity, daily time spent watching television, studying in bed, sitting posture to write and use the computer, and way of carrying the backpack. CONCLUSIONS The prevalence of back pain in schoolchildren is high and it is associated with demographic, behavior and heredity aspects. PMID:27305406
Strategies in assessing post operative pain--a South African study.
Klopper, Hester; Andersson, Helena; Minkkinen, Maria; Ohlsson, Cecilia; Sjöström, Björn
The purpose of this validation study was to describe strategies used in postoperative pain assessment among a group of nurses in South Africa. A mixed qualitative and quantitative study was conducted in a 950-bed academic hospital complex. Surgical nurses (n = 12) carried out pain assessments of postoperative patients (n = 36) in pain. Data were collected using detailed interviews and pain intensity was estimated on a visual analogue scale (VAS, 0-10 cm). Nurses used four categories of criteria (a) how the patient looks, (b) what the patient says, (c) the patient's way of talking, and (d) experience of similar circumstances and drew on their past experiences in five different ways: (a) some patients report lower pain intensity than expected, (b) a typology of patients, (c) a focus on listening to patients, (d) what to look for, and (e) what to do for patients were identified. The system of categories described by Sjöström [Sjöström B. Assessing acute postoperative pain. Assessment strategies and quality of clinical experience and professional role. Göteborg: Acta Universitatis Gothoburgensis; 1995] was valid for this sample with an additional category. The different categories seem to be complementary and necessary for assessing pain in others. The findings have implications for professionals who provide care for patients in pain.
Postoperative Pain, an Unmet Problem in Day or Overnight Italian Surgery Patients: A Prospective Study
Antonielli D'Oulx, Maria Delfina; Paradiso, Rosetta; Perretta, Laura; Dimonte, Valerio
Background. Because of economic reasons, day surgery rates have steadily increased in many countries and the trend is to perform around 70% of all surgical procedures as day surgery. Literature shows that postoperative pain treatment remains unfulfilled in several fields such as orthopedic and general surgery patients. In Italy, the day surgery program is not yet under governmental authority and is managed regionally by local practices. Aim. To investigate the trends in pain intensity and its relation to type of surgeries and pain therapy protocols, in postoperative patients, discharged from three different Ambulatory Surgeries located in North West Italy (Piedmont region). Method. The present study enrolled 276 patients who undergone different surgical procedures in ambulatory regimen. Patients recorded postoperative pain score twice a day, compliance with prescribed drugs, and pain related reasons for contacting the hospital. Monitoring lasted for 7 days. Results. At discharge, 72% of patients were under weak opioids, 12% interrupted the treatment due to side effects, 17% of patients required extra drugs, and 15% contacted the hospital reporting pain problems. About 50% of patients experienced moderate pain during the first day after surgery. Results from our study show that most of the patients experienced avoidable pain after discharge. PMID:28115878
Temporal changes in cortical activation during conditioned pain modulation (CPM), a LORETA study.
Moont, Ruth; Crispel, Yonatan; Lev, Rina; Pud, Dorit; Yarnitsky, David
For most healthy subjects, both subjective pain ratings and pain-evoked potentials are attenuated under conditioned pain modulation (CPM; formerly termed diffuse noxious inhibitory controls, or DNIC). Although essentially spinal-bulbar, this inhibition is under cortical control. This is the first study to observe temporal as well as spatial changes in cortical activations under CPM. Specifically, we aimed to investigate the interplay of areas involved in the perception and processing of pain and those involved in controlling descending inhibition. We examined brief consecutive poststimulus time windows of 50 ms using a method of source-localization from pain evoked potentials, sLORETA. This enabled determination of dynamic changes in localized cortical generators evoked by phasic noxious heat stimuli to the left volar forearm in healthy young males, with and without conditioning hot-water pain to the right hand. We found a CPM effect characterized by an initial increased activation in the orbitofrontal cortex (OFC) and amygdala at 250-300 ms poststimulus, which was correlated with the extent of psychophysical pain reduction. This was followed by reduced activations in the primary and secondary somatosensory cortices, supplementary motor area, posterior insula, and anterior cingulate cortex from 400 ms poststimulus. Our findings show that the prefrontal pain-controlling areas of OFC and amygdala increase their activity in parallel with subjective pain reduction under CPM, and that this increased activity occurs prior to reductions in activations of the pain sensory areas. In conclusion, achieving pain inhibition by the CPM process seems to be under control of the OFC and the amygdala.
Training the trainer: An educational course for training pain nursing specialists supported by the International Association for the Study of Pain (IASP).
Cui, Jing; Zhou, Lingjun; Zhang, Lingjuan; Li, Li; Zhao, Jijun
To train pain nursing specialists through a pain education program, 20 nurses from six hospitals in Shanghai Province and seven in six provinces of China received the training of 2-month pain education and 4-month clinical practice. This nonrandomized pilot study examined the results of tests before and after the program, case report evaluations, future plan evaluations, clinical practice, and satisfaction questionnaire. After the program, the score of the test increased significantly compared with that before the program (44.1 ± 3.19; paired-sample t = 10.363; p < .0001). All of the participants thought that the program had broadened their vision, 19 (95%) thought that the program had raised the level of their theoretical knowledge in pain management, 17 (85%) thought that the program had improved their skills in clinical practice, and 15 (75%) thought that the program had played a role in enhancing their research abilities. Considering the whole program, most students (n = 17; 85%) were quite satisfied, and 3 (15%) were simply satisfied. By content analysis of the opening questions, we found that the participants had deeper and broader ideas about nurses' role and pain nursing specialists' responsibilities in pain management. The program improved nurses' attitudes, knowledge, and skills in pain management. The participants recognized pain nursing specialists' responsibilities in pain management more clearly.
Low back pain in car drivers: A review of studies published 1975 to 2005
NASA Astrophysics Data System (ADS)
Gallais, Lenka; Griffin, Michael J.
This review investigates whether there is evidence of an association between car driving and low back pain, and evidence that whole-body vibration contributes to low back pain in car drivers. The evidence of an association between various physical, psychosocial and individual factors and low back pain in car drivers was also investigated. From 23 epidemiological studies of low back problems in groups that reported car driving, nine studies fulfilled simple criteria for detailed review: four cross-sectional studies, three case-control studies and two longitudinal studies. The definition of low back pain was often unclear and, mostly, the physiological mechanisms causing low back pain were not considered. Eight of the nine studies concluded that there was an increase in low back pain among car drivers but there was little consideration of the influence of the many physical factors, individual factors and psychosocial factors that might be associated with an increase in low back pain. Consequently, there is insufficient evidence to form a conclusion on whether whole-body vibration, postural stressors or other factors, specific or not specific to driving, are common causes of low back problems in car drivers.
Tin-117m(4+)-DTPA for palliation of pain from osseous metastases: A pilot study
Atkins, H.L.; Mausner, L.F.; Srivastava, S.C. ||
The physical and biological attributes of {sup 117m}Sn(4+)-DTPA indicate that it should be an effective agent for palliative therapy of painful bony metastatic disease. The aim of this study was to evaluate whether or not this agent could effectively reduce pain while sparing the hemopoietic marrow from adverse effects. Fifteen patients (10 males and 5 females) with painful bony metastases from various primary cancers were included in the study. Seven patients received 1.22 to 3.11 MBq/kg of {sub 117m}Sn intravenously (Group 1) and eight patients received 4.85 to 5.77 MBq/kg (Group 2). All but one were treated as outpatients and followed for a minimum of 2 mo. In the first group, pain relief was nonassessable in four patients because of death or additional treatment of soft-tissue disease by another modality. One patient had no relief of pain, one had complete relief of pain and one had transient relief of pain. No myelotoxicity was observed. For Group 2, three patients achieved complete relief of pain, two good relief, two partial relief and one began to experience pain relief when he suffered a pathological fracture 2 mo most-treatment. None of these patients had myelotoxicity. Tin-117m(4+)-DTPA can reduce pain from metastatic disease to bone without inducing adverse reactions related to bone marrow. Further studies are needed to assess tolerance levels for the bone marrow and to evaluate response rates and duration of effect. 6 refs., 4 figs., 4 tabs.
Gynecological Management of Neuropathic Pain
TU, Frank F.; HELLMAN, Kevin; BACKONJA, Miroslav
Obstetrician/gynecologists often are the initial management clinicians for pelvic neuropathic pain. While treatment may require comprehensive team management and consultation with other specialists, there a few critical and basic steps that can be performed on an office visit that offer the opportunity to significantly improve quality of life in this patient population. A key first step is a thorough clinical examination to physically map the pain site and identify potentially involved nerves. Only limited evidence exists on how best to manage neuropathic pain, but generally a combination of surgical, manipulative or pharmacological methods should be considered. Experimental methods for more precisely characterizing the nature of the nerve dysfunction exist to diagnose and treat neuropathic pain, but additional scientific evidence is needed to unanimously recommend these options. In the meantime, an approach adopted from guidelines of the International Association for Study of Pain tailored for gynecological pain is suggested. PMID:21777899
Do cry features reflect pain intensity in preterm neonates? A preliminary study.
Johnston, C C; Sherrard, A; Stevens, B; Franck, L; Stremler, R; Jack, A
The purpose of this study was to investigate if cries from preterm neonates would reflect changes in pain intensity following interventions. The cries from 25 preterm neonates from an original sample of 122 were audiorecorded while the infant was undergoing heelstick during a randomized crossover design testing the efficacy of: pacifier with sucrose or water, or prone position as compared to standard care. Both pacifier conditions reduced procedural pain according to a validated composite pain measure (the Premature Infant Pain Profile). There were proportionately fewer cries in the two pacifier groups compared to the prone positioning and standard care groups, and cry duration was positively correlated with PIPP scores. However, neither cry duration nor fundamental frequency reflected group differences. Further research is needed to determine if cry is a sensitive and valid indicator of pain in preterm infants.
Decision-making processes for the self-management of persistent pain: a grounded theory study.
Fenwick, Clare; Chaboyer, Wendy; St John, Winsome
Persistent pain negatively impacts upon the individual suffering this condition. Almost all care related to persistent pain is self-managed. Decision-making is a critical skill of the self-manager and without these skills it would be improbable that effective self-management would emerge. However, current theories regarding decision-making and self-management have not adequately accounted for the many difficulties faced by individuals enduring persistent pain and the consequences of these experiences for the decision-maker. This grounded theory study revealed that individuals will transform into three distinct types of decision-makers using three different styles of decision-making in response to the many and varied problems related to the experience of persistent pain. These findings will provide nurses with valuable information to better equip individuals with persistent pain through the decision-making processes necessary for successful self-management.
Working memory load modulates the neural response to other's pain: Evidence from an ERP study.
Cui, Fang; Zhu, Xiangru; Luo, Yuejia; Cheng, Jiaping
The present study investigated the time course of processing other's pain under different conditions of working memory (WM) load. Event-related potentials (ERPs) were recorded while the participants held two digits (low WM load) or six digits (high WM load) in WM and viewed pictures that showed others who were in painful or non-painful situations. Robust WM-load × Picture interactions were found for the N2 and LPP components. In the high WM-load condition, painful pictures elicited significantly larger amplitudes than non-painful pictures. In the low WM load condition, the difference between the painful and non-painful pictures was not significant. These ERP results indicate that WM load can influence both the early automatic N2 component and late cognitive LPP component. Compared with high WM load, low WM load reduced affective arousal and emotional sharing in response to other's pain and weakened the cognitive evaluation of task irrelevant stimuli. These findings are explained from the load theory perspective.
Moral judgment modulates neural responses to the perception of other's pain: an ERP study
Cui, Fang; Ma, Ning; Luo, Yue-jia
Morality and empathy are both crucial in building human society. Yet the relationship between them has been merely explored. The present study revealed how the morality influenced empathy for pain by comparing the ERPs elicited by pictures showing the targets' in pain primed by different moral information about the targets. We found that when the target was a moral one or a neutral one, the painful pictures elicited significantly larger amplitude in N2 than the non-painful pictures, but when the target was an immoral one, the difference between the amplitudes of N2 component elicited by painful and non-painful pictures became insignificant. We proposed that this effect was induced by the decreased affective arousal when observing an immoral person in pain. The reduced neural response towards the immoral one's pain can keep us alert when we face the potentially dangerous people thereby increasing our chance of survival. SLORTEA results showed the source of this difference in N2 localized in the ventral medial prefrontal cortex (vmPFC) and the rostral anterior cingulate cortex (rACC) areas. PMID:26865250
EDIN Scale Implemented by Gestational Age for Pain Assessment in Preterms: A Prospective Study
Mosca, F.
Background. Chronic neonatal pain can lead to long-term adverse effects on the immature brain. EDIN scale for prolonged pain might not be fully suitable for premature infants. We aimed to test a modified EDIN scale, adding postmenstrual age (PMA) as a sixth item (EDIN6). Methods. In a two-phase prospective study, pain was assessed in all neonates admitted in our NICU. In T1 EDIN was applied; in T2 EDIN6 with additional scores of 2, 1, and 0, respectively, for 25–32, 33–37, and >37 weeks PCA was tested. Scores > 6 suggested pain. The nursing staff was given a questionnaire to evaluate EDIN and EDIN6. Results. A total of 15960 pain assessments were recorded (8693 in T1; 7267 in T2). With EDIN6, cumulative detection of pain almost tripled (117/7267 versus 52/8693, p = 0.001). Main differences were found among less mature categories (50/1472 versus 17/1734, p = 0.001 in PCA 25–32; 26/2606 versus 10/4335, p = 0.001 in PMA 33–37; 41/3189 versus 25/2624, p = 0.26 in PMA > 37). Adequacy of pain assessment in lower PMA was judged "medium-high" in 13,4% of nurses in T1 and 71,4% in T2. Conclusions. EDIN6 may allow improved evaluation of pain in preterm infants. PMID:28271074
Wang, Cheng-Hsu; Lee, Shiu-Yu C
Pain is a burdensome symptom that can commonly exist chronically along the cancer trajectory. Uncontrolled pain will impact on cancer patients' quality of life, even further negatively affect cancer survivors' employment. Based on systemic reviews of studies for past 10 years, the paper reported that although there is enormous advancement on the knowledge of cancer pain and pain management, studies still documented undertreatment of cancer pain globally. Additionally, pain distress a significant portion of cancer survivors. The pain in cancer survivors distinct from the pain related with cancer, instead emphasize on pain related with cancer treatment, such as neuropathic pain, muscular syndrome. Evidence-based pain management with common pain problems in cancer survivors is lacking. Further studies are needed to understand the pain in cancer survivors and to develop effective strategies in helping cancer survivors to manage their pain.
Chronic regional muscular pain in women with precise manipulation work. A study of pain characteristics, muscle function, and impact on daily activities.
Henriksson, K G; Bäckman, E; Henriksson, C; de Laval, J H
Pain characteristics, muscle function and impact on daily activities were studied in 39 women with chronic regional muscular pain (RMP). They were all blue-collar workers in work involving precise manipulations. The main location of the pain was in the neck-shoulder region. Nineteen age-matched women with fibromyalgia (FM) were studied in the same way as the RMP patients. Thirty-seven women with no pain and with the same age and weight as the RMP patients served as reference group with respect to muscle strength and endurance. A follow-up study was done with respect to pain distribution and other pain characteristics 20 months after the initial examination. The findings were of the same nature in the RMP and the FM groups. The intensity of pain, the lowering of pain threshold for pressure, and the degree of sleep disturbance were greater in the FM than in the RMP group. Isometric muscle strength and static muscular endurance were reduced in both FM and RMP compared to reference values. The reduction in strength and endurance was greater in FM than in RMP. Even if the impact on everyday activities were greater in FM than in RMP, the impact was substantial in RMP patients also, for example with regard to work capacity. There were no transitions from RMP to FM during the 20 months to follow-up. Three FM patients, however, did not meet the ACR criteria for FM at follow-up.
Neuronal correlates of gastric pain induced by fundus distension: a 3T-fMRI study.
Lu, C-L; Wu, Y-T; Yeh, T-C; Chen, L-F; Chang, F-Y; Lee, S-D; Ho, L-T; Hsieh, J-C
Visceral hypersensitivity in gastric fundus is a possible pathogenesis for functional dyspepsia. The cortical representation of gastric fundus is still unclear. Growing evidence shows that the insula, but not the primary or secondary somatosensory region (SI or SII), may be the cortical target for visceral pain. Animal studies have also demonstrated that amygdala plays an important role in processing visceral pain. We used fMRI to study central projection of stomach pain from fundus balloon distension. We also tested the hypothesis that there will be neither S1 nor S2 activation, but amygdala activation with the fundus distension. A 3T-fMRI was performed on 10 healthy subjects during baseline, fullness (12.7 +/- 0.6 mmHg) and moderate gastric pain (17.0 +/- 0.8 mmHg). fMRI signal was modelled by convolving the predetermined psychophysical response. Statistical comparisons were performed between conditions on a group level. Gastric pain activated a wide range of cortical and subcortical structures, including thalamus and insula, anterior and posterior cingulate cortices, basal ganglia, caudate nuclei, amygdala, brain stem, cerebellum and prefrontal cortex (P < 0.001). A subset of these neuronal substrates was engaged in the central processing of fullness sensation. SI and SII were not activated during the fundus stimulation. In conclusion, the constellation of neuronal structures activated by fundus distension overlaps the pain matrices induced musculocutaneous pain, with the exception of the absence of SI or SII activation. This may account for the vague nature of visceral sensation/pain. Our data also confirms that the insula and amygdala may act as the central role in visceral sensation/pain, as well as in the proposed sensory-limbic model of learning and memory of pain.
Disorders of Consciousness: Painless or Painful Conditions?—Evidence from Neuroimaging Studies
Pistoia, Francesca; Sacco, Simona; Stewart, Janet; Sarà, Marco; Carolei, Antonio
The experience of pain in disorders of consciousness is still debated. Neuroimaging studies, using functional Magnetic Resonance Imaging (fMRI), Positron Emission Tomography (PET), multichannel electroencephalography (EEG) and laser-evoked potentials, suggest that the perception of pain increases with the level of consciousness. Brain activation in response to noxious stimuli has been observed in patients with unresponsive wakefulness syndrome (UWS), which is also referred to as a vegetative state (VS), as well as those in a minimally conscious state (MCS). However, all of these techniques suggest that pain-related brain activation patterns of patients in MCS more closely resemble those of healthy subjects. This is further supported by fMRI findings showing a much greater functional connectivity within the structures of the so-called pain matrix in MCS as compared to UWS/VS patients. Nonetheless, when interpreting the results, a distinction is necessary between autonomic responses to potentially harmful stimuli and conscious experience of the unpleasantness of pain. Even more so if we consider that the degree of residual functioning and cortical connectivity necessary for the somatosensory, affective and cognitive-evaluative components of pain processing are not yet clear. Although procedurally challenging, the particular value of the aforementioned techniques in the assessment of pain in disorders of consciousness has been clearly demonstrated. The study of pain-related brain activation and functioning can contribute to a better understanding of the networks underlying pain perception while addressing clinical and ethical questions concerning patient care. Further development of technology and methods should aim to increase the availability of neuroimaging, objective assessment of functional connectivity and analysis at the level of individual cases as well as group comparisons. This will enable neuroimaging to truly become a clinical tool to reliably investigate
Experimental Study of the Current Filamentation Instability
NASA Astrophysics Data System (ADS)
Allen, Brian; Muggli, Patric; Silva, Luis O.; Martins, Joana; Yakimenko, Vitaly; Fedurin, Mikhail; Kusche, Karl; Babzien, Marcus; Huang, Chengkun; Mori, Warren
The Current Filamentation Instability (CFI) is of central importance for the propagation of relativistic electron beams in plasmas. CFI has potential relevance to astrophysics, afterglow of gamma ray bursts, inertial confinement fusion, energy transport in the fast-igniter concept, and places an upper limit on the plasma density and accelerating gradient in PWFA's. An experimental study at the Accelerator Test Facility at Brookhaven National Laboratory with the 60MeV e^- beam and cm length plasma. The experiment included the systematic study and characterization of the instability as a function of the beam charge and plasma density. The transverse beam profile is measured directly at the plasma exit using OTR. Experimental results show the transition from plasma focusing to CFI near kpσr=1 characterized by the appearance of multiple (1-5) beam filaments and scaling of the transverse filament size with the plasma skin depth. Suppression of the instability is seen by lowering the growth rate of the instability by reducing the beam charge. The experimental results are in excellent agreement with theory and simulations and we present and discuss simulation and experimental results.
Experimental and computational study of thaumasite structure
Scholtzová, Eva; Kucková, Lenka; Kožíšek, Jozef; Pálková, Helena; Tunega, Daniel
The structure of thaumasite has been studied experimentally by means of a single crystal X-ray diffraction and FTIR methods, and theoretically using density functional theory (DFT) method. Very good agreement was achieved between calculated and experimental structural parameters. In addition, calculations offered the refinement of the positions of the hydrogen atoms. The detailed analysis of the hydrogen bonds existing in the thaumasite structure has been performed. Several types of hydrogen bonds have been classified. The water molecules coordinating Ca{sup 2+} cation act as proton donors in moderate O-H···O hydrogen bonds formed with CO₃⁻²and SO₄⁻² anions. The multiple O-H···O hydrogen bonds exist among water molecules themselves. Finally, relatively weak hydrogen bonds form water molecules with the OH groups from the coordination sphere of the Si(OH)₆⁻² anion. Further, calculated vibrational spectrum allowed complete assignment of all vibrational modes which are not available from the experimental spectrum that has a complex structure with overlapped bands, especially below 1500 cm⁻¹. Highlights: • The thaumasite structure was studied experimentally and using DFT method. • We used DFT method for the refinement of the positions of hydrogen atoms. • A detailed analysis of the hydrogen bonds was done. • A complete assignment of all bands to particular types of vibrations was done.
Detecting the neuropathic pain component in the clinical setting: a study protocol for validation of screening instruments for the presence of a neuropathic pain component
Background The presence of nerve damage plays a key role in the development and prognosis of chronic pain states. Assessment of the presence and severity of a neuropathic pain component (NePC) is key in diagnosing chronic pain patients. Low back pain (LBP) and neck and shoulder pain (NSP) are highly prevalent and clinically important medical and societal problems in which a NePC is frequently present. The more severe the NePC, the worse the course of the pain, its prognosis and the results of treatment. Reliable and standardised diagnosis of the NePC remains difficult to achieve. Standardized and validated screening tools may help to reliably identify the NePC in individual chronic pain patients. The aim of this study is to validate the Dutch language versions of the PainDETECT Questionnaire (PDQ-Dlv) and the 'Douleur Neuropathique 4 Questions' (DN4-Dlv) for use in primary and specialist medical care settings to screen for a NePC in patients with chronic pain due to (1) LBP, (2) NSP or (3) known peripheral nerve damage (PND). Methods/design The study design is cross-sectional to assess the validity of the PDQ-Dlv and the DN4-Dlv with 2 weeks follow-up for test-retest reliability and 3 months follow-up for monitoring and prognosis. 438 patients with chronic pain due to (1) LBP, (2) NSP or (3) PND. will be included in this study. Based on the IASP definition of neuropathic pain, two physicians will independently assess whether the patient has a NEPC or not. This result will be compared with the outcome of the PDQ-Dlv & DN4-Dlv, the grading system for neuropathic pain, bed side examination and quantitative sensory testing. This study will further collect data regarding prevalence of NePC, general health status, mental health status, functioning, pain attribution and quality of life. Discussion The rationale for this study is to provide detailed information on the clinimetric quality of the PDQ-Dlv and DN4-Dlv in Dutch speaking countries. Our innovative multi
A Descriptive Study of a Perioperative Pain Service Program
stems from the hypothesis that pain is one Component of the neural, endocrine, metabolic, and inflammatory interactions that make up the stress...care postoperatively and "to require admission to the ICU for the administration of epidural morphine is to deprive some patients of the benefits of...late. Early respiratory depression occurs as a result of uptake via the vasculature in the spinal cord area. Plasma concentrations of morphine
A Descriptive Study of a Perioperative Pain Service Program
the Renaissance. Leading the forefront was Renee Descartes , a French mathematician. He described nerves as hollow tubes through which fine threads...Sensations had to interact with the mind or soul, which Descartes considered to be separate from the body and unaffected by external and mechanical...forces. Integration of the mind and body, according to Descartes , occurred within the pineal gland. Pain, therefore, was a Co-axial Narcotics 17 state
Progress in Genetic Studies of Pain and Analgesia
LaCroix-Fralish, Michael L.
Interindividual variability in pain sensitivity and the response to analgesic manipulations remains a considerable clinical challenge as well as an area of intense scientific investigation. Techniques in this field have matured rapidly so that much relevant data have emerged only in the past few years. Our increasing understanding of the genetic mediation of these biological phenomena have nonetheless revealed their surprising complexity. This review provides a comprehensive picture and critical analysis of the field and its prospects. PMID:18834308
A descriptive study of Korean nurses' perception of pain and skin tearing at dressing change.
Kim, Jung Yoon; Kim, Na Kyung; Lee, Yun Jin
This study aimed to investigate Korean nurses' level of awareness of pain and skin tearing in wound bed and/or peri-wound skin at dressing change. A descriptive study was performed. Convenience sampling was employed and registered nurses were recruited from attendees of continuing education program. A total of 399 participants (RN) completed questionnaire. Data was collected from September to November 2014. Many of them perceived skin tearing and wound related pain associated with dressing changing, but most of them did not assess and record pain and skin tearing at dressing change. More than half of respondents reported that they did not provide nursing intervention to prevent pain and skin tearing. Many of them reported that a systematic educational program for preventing pain and skin tearing at dressing change was needed. In conclusion, many of respondents were aware of pain and skin tearing at dressing change, but did not take any further necessary measures, including nursing intervention, for the most appropriate, systematic pain and skin tearing management. Therefore, this study suggested that a systematic and comprehensive educational program for Korean healthcare professions needs to be developed and implemented in Korea's hospital settings.
Therapeutic and experimental therapeutic studies on acupuncture and itch: review of the literature.
Carlsson, C P; Wallengren, J
Itch accompanies most inflammatory skin diseases but may occur as a solitary sensation in otherwise normal skin. Chronic itch often requires combined treatments but some cases remain therapy resistant. Complementary medicine is becoming increasingly popular among patients. Acupuncture is the oldest and most well-studied alternative option with evidence-based effect on pain. This article summarizes the rational for the use of acupuncture in treatment of itch and reviews therapeutic and experimental therapeutic studies on acupuncture and itch.
Temporal associations between spouse criticism/hostility and pain among patients with chronic pain: a within-couple daily diary study.
Burns, John W; Peterson, Kristina M; Smith, David A; Keefe, Francis J; Porter, Laura S; Schuster, Erik; Kinner, Ellen
Chronic musculoskeletal pain can strain marriages, perhaps even to the point of engendering spouse criticism and hostility directed toward patients. Such negative spouse responses may have detrimental effects on patient well-being. While results of cross-sectional studies support this notion, we extended these efforts by introducing expressed emotion (EE) and interpersonal theoretical perspectives, and by using electronic diary methods to capture both patient and spouse reports in a prospective design. Patients with chronic low back pain (CLBP) and their spouses (N = 105 couples) reported on perceived spouse behavior and patient pain 5 times/day for 14 days using Personal Data Assistants (PDAs). Concurrent and lagged within-couple associations between patient's perceptions of spouse criticism/hostility and patient self-reported pain and spouses' observations of patient pain behaviors revealed that (1) patient perceived spouse criticism and hostility were correlated significantly with pain intensity, and spouse observed patient pain behavior was related significantly with patient perceived hostility at the same time point; (2) patient perceived spouse hostility significantly predicted patient pain intensity 3 hours later, and spouse observed pain behaviors significantly predicted patient perceived spouse hostility 3 hours later. Results support both EE and interpersonal models, and imply that a comprehensive model would combine these conceptualizations to fully illustrate how spouse criticism/hostility and patient pain interact to produce a negative spiral. Given that marital interactions are amenable to clinical intervention, improved insight into how spouse behavior and patient pain are tightly linked will encourage productive translational efforts to target this neglected area.
Does going to an amusement park alleviate low back pain? A preliminary study
Sakakibara, Toshihiko; Wang, Zhuo; Kasai, Yuichi
Background Low back pain is often called nonspecific pain. In this type of low back pain, various emotions and stress are known to strongly affect pain perception. The purpose of this study is to investigate how the degree of low back pain changes in people with chronic mild low back pain when they are inside and outside of an amusement park where people are supposed to have physical and psychological enjoyment. Methods The subjects were 23 volunteers (13 males and 10 females) aged 18 to 46 years old with a mean age of 24.0 years who had chronic low back pain. Visual analog scale (VAS) scores of low back pain and salivary amylase levels (kIU/L) of all subjects were measured at five time points: immediately after getting on the bus heading for the amusement park; 10 minutes, 1 hour (immediately after boarding the roller coaster), and 3 hours (immediately after exiting the haunted house) after arriving at the amusement park; and immediately before getting off the bus returning from the park. Results The three VAS values in the amusement park (10 minutes, 1 hour, and 3 hours after arriving at the amusement park) measured were significantly lower (P < 0.05) when compared with the other two values measured immediately after getting