stroke is known to be a common cause of neurological diseases and disorders that cause 
 swallowing , with incidence of swallowing disorders after stroke reportedly being as high as 
 3050%1 , 2 . swallowing disorders due to stroke increase the risk of death due 
 to complications such as aspiration pneumonia , malnutrition , and dehydration3 . tracheal aspirations are commonly found in 
 swallowing disorders ; therefore , early prognosis appropriate treatments are important4 . respiratory and swallowing occur by several anatomical structures and provide important 
 functions associated with airway protection , such as coughing and swallowing action . these 
 airway - protective actions are initiated by a signal that passes from the medulla oblongata 
 to the pharynx , larynx , and trachea , and the receptors of the agency signal to training 
 start by communicating and share the brainstem network called the behavior control 
 assemblies ( bcas)5 . stroke is often 
 accompanied by a central diaphragmatic dysfunction , with movement disorders caused by stroke 
 imposing limitations on diaphragmatic motion , which leads to decreased lung volume6 . in a previous study evaluating the risk of 
 tracheal aspiration through a quantitative measure of voluntary cough , the maximal 
 expiratory volume during inspiratory and expiratory airway suction in stroke with aspiration as such , the maximum expiratory volume in patients with swallowing 
 disorders is closely related to tracheal aspiration , which is often used as an indicator to 
 predict swallowing disorder8 . expiratory muscle strength training ( emst ) has consistently been reported as a remedial 
 approach to swallowing treatment that strengthen muscles associated with swallowing by 
 exhalation through the oral9 , 11 . the suprahyoid muscle causes the anterior - superior 
 movement of the hyoid bone in the swallowing process and facilitates airway protection and 
 normal swallowing during opening of the cricopharyngeal muscle10 . emst is a strength training method that employs 
 resistance and it is known to effectively improve activation of suprahyoid muscles and 
 movement of the hyoid bone11 , 12 . wheeler et al . reported that emst is an effective way to 
 induce suprahyoid muscle activation through surface surface electromyography ( semg)11 , which is reportedly effective in patients 
 with swallowing disorders caused by decreased movement of the hyoid bone . emst also has been 
 reported as an effective method of suprahyoid muscle activation in huntington s disease13 . although emst is a potential remedial approach for swallowing disorder , it has only been 
 investigated in the elderly and in patients with parkinson s disease and huntington s 
 disease11,12,13 , 20 , while its effects in stroke patients have yet to be evaluated . therefore , in this study , acute stroke patients with dysphagia were monitored and examined 
 to determine the effects of emst . the specific purpose of this study was to identify the 
 effects of emst on swallowing in acute stroke patients with dysphagia . this study included 18 stroke patients with dysphagia and was performed at i hospital in 
 korea from 20142015 . participant selection criteria were as follows : ( 1 ) onset of no more 
 than 1 month , ( 2 ) the person with swallowing disorder of pharyngeal stage through 
 videofluoroscopic swallowing study ( vfss ) , such as aspiration , invasion or residues of 
 pharyngeal stage , ( 3 ) no oral stage problems , such as mastication and oral facial muscle 
 movement , ( 4 ) mmse of more than 24 , ( 5 ) no specific medical problems , including 
 respirational problems . the general characteristics of the subjects are summarized in table 1table 
 1.general characteristics of both groupsexperimental group ( n=9)control group ( n=9)gender ( male / female)6/36/3age ( years)63.0  
 5.863.1  5.2stroke type 
 ( ischemic / hemorrhagic)6/37/2affected side ( left / right)4/55/4onset duration 
 ( days)21.4  5.121.1  
 4.0mmse25.9  2.526.4 exclusion criteria were as follows : ( 1 ) 
 person without the appropriate lips closed , ( 2 ) significant facial paralysis , ( 3 ) 
 tracheostomy and percutaneous endoscopic gastrostomy , ( 4 ) hypertension . all of the protocols 
 used in this study were approved by gachon university . before participation , the procedures , 
 risks , and benefits were explained and all participants gave their informed consent . the 
 participants rights were protected according to the guidelines of the gachon 
 university . mmse : mini mental state 
 examination all participants were randomly assigned to either an experimental group ( n=9 ) or a control 
 group ( n=9 ) . all participants performed traditional swallowing rehabilitation therapy in 30 
 minute sessions five times a week for four weeks . expiratory muscle strength training was 
 only provided to the experimental group in 30 minute sessions . traditional swallowing 
 treatment was composed of orofacial exercises , thermal - tactile stimulation , the mendelson 
 maneuver , effortful swallow , and supraglottic maneuver . first , 
 patients were provided with a mouthpiece to blow into , after which the nasal cavity was 
 closed using forceps . the personal maximal expiratory pressure ( mep ) wheeler et al . were trained with a threshold value of 70% , it based on the 
 personal mep11 . the training consisted of 
 taking a deep breath and biting a mouthpiece , during which time the patient was told to blow 
 faster and stronger . each patient received seven trainings per session , five times a week 
 for four weeks . breaks of 30 seconds were provided after one session . to evaluate the swallowing function of patients with dysphagia , functional dysphagia scale 
 ( fds ) , penetration - aspiration scale ( pas ) , vallecular residue ( vr ) , and pyriform sinuses 
 residue ( pr ) were assessed . the evaluation was conducted by an occupational therapist with 
 5  years of experience with swallowing rehabilitation . functional dysphagia scale ( fds ) is a quantification of the degree of swallowing disorder , 
 and testing to determine the effect of swallowing disorders quantitatively . a score of 0 was 
 considered normal , while a score of 100 indicated the greatest severity . the penetration - aspiration scale ( pas ) was divided into eight stages depending on laryngeal 
 penetration and trachea aspiration based on the vocal fold , with a higher stage indicating 
 increased severity of aspiration15 . also 
 pas after swallowing the food , the score is determined by the presence or absence of 
 invasion or aspiration of food comes out through coughing . vallecular and 
 pyriform sinuses residue was divided into 03 grades , with higher grades indicating greater 
 swallowing dysfunction . specifically , grade 0 indicating no residue , grade 1 indicated 25% 
 or less , grade 2 indicated 2550% , and grade 3 was more than 50%16 . the differences between 
 before and after intervention were compared with wilcoxon signed - rank tests and differences 
 within a group before and baseline score , change score of dependent variable of were tested 
 using the mann - whitney u test . comparison of swallowing function within and between two groups is shown 
 in table 2table 
 2.comparison of swallowing function within and between two 
 groupsexperimental group ( n=9)control group ( n=9)beforeafter 4-weekschangesbeforeafter 4-weekschangesfds 
 total28.22  5.3318.44  
 5.64**9.78  2.7327.56  
 5.6422.00  6.00*5.56  
 4.22vr1.44  0.530.33  0.50**1.11  0.331.67  0.711.11  0.60*0.56  0.53pr1.11  
 0.600.56  0.53*0.56  0.531.11  0.600.89  0.600.22  0.44pas4.78  
 1.562.11  1.27**2.67  
 0.875.00  1.323.89 1.27*1.11  
 1.05all values are the mean  standard 
 deviation ( sd ) . fds : functional dysphagia scale ; vr : vallecular residue ; pr : pyriform 
 sinuses residue ; pas : penetration - aspiration scale*p<0.05 , 
 * * p<0.01significant difference between groups 
 ( p<0.05 ) . in the both experimental and control 
 groups , significant improvement was observed in all variables ( p<0.05 ) , except for pr in 
 the control group . in addition , experimental group showed great improvement than the control 
 group in the fds , vr and pas ( p<0.05 ) . fds : functional dysphagia scale ; vr : vallecular residue ; pr : pyriform 
 sinuses residue ; pas : penetration - aspiration scale significant difference between groups 
 ( p<0.05 ) this study was conducted to verify the effects of emst on swallowing function in acute 
 stroke patients . the experimental group showed a significant improvement in all evaluated 
 factors , while the control group showed a significant improvement in all factors except 
 pyriform sinuses residue . comparison between groups revealed significant improvements in the 
 fds , vr , and pas in the experimental group relative to the control group . these results 
 provide evidence that emst improves the swallowing function of patients with acute 
 stroke . in this study , yoon et al . reported laryngeal lift 
 and pharyngeal residue and a significant improvement in the pharyngeal transit time of food 
 when applying 75% emst resistance17 . these findings are consistent with the decreased vallecular residue observed in the present 
 study . in this study it is believed 
 that the pyriform sinuses residue is related to upper esophageal sphincter opening , which is 
 caused by a hyolaryngeal excursion to pull forward the hyoid bone and posterior contraction 
 of the longitudinal pharyngeal muscle18 . however , this study did not measure changes in the upper esophageal sphincter opening . in this study , intervention of emst was carried out for four weeks . was 
 reported reduced aspiration applied to parkinson s patients over a four - week emst19 , while troche et al . reported a 
 significant reduction in aspiration following emst for four weeks20 . similarly , the present study confirmed the effectiveness 
 of emst for four weeks at reducing aspiration and vallecular residue , as well as improving 
 fds , which is similar to the results of previous studies . reduced respiratory function is commonly observed in stroke patients21 . thus , acute stroke patients in need of intensive 
 rehabilitation will be feel fatigue easily during aerobic exercise . moreover , problems due 
 to fatigue will have adverse effects on quality of life and interfere with functional 
 recovery . accordingly , emst training has the potential to improve respiratory function , as 
 well as swallowing disorders , thereby improving overall treatment of stroke patients . accordingly , future long - term studies of more patients are 
 needed . in conclusion , the present study was conducted to evaluate the effects of emst 
 intended for patients with acute stroke on swallowing . the results revealed that emst may 
 have a positive effect on the swallowing of acute stroke patients .
[ purpose ] this study was conducted to identify the effects of expiratory muscle strength 
 training on swallowing function in acute stroke patients with dysphagia . 
 [ subjects and 
 methods ] a total of 18 stroke patients with dysphagia were enrolled in the study . 
 all 
 participants were randomly assigned to either an experimental group ( n=9 ) or a control 
 group ( n=9 ) . 
 all participants performed traditional - swallowing rehabilitation therapy in 
 30-minute sessions five times a week for four weeks ; however , only the experimental group 
 received expiratory muscle strength training . 
 [ results ] both groups showed significant 
 improvements after mediation . 
 when compared with the control group , the functional 
 dysphagia scale , vallecular residue , and penetration - aspiration scale were significantly 
 improved in the experimental group . 
 [ conclusion ] expiratory muscle strength training is an 
 effective intervention for impaired swallowing function in acute strike patients with 
 dysphagia .