the ubiquitous nature of cognitive , gait , and urinary problems in the elderly makes the diagnosis of a unitary process to explain all three dysfunctions difficult , if not illogical . since the 1960s , however , it has been realized that a small number of adults ( particularly those over 70 , with equal frequency in both sexes ) have a triad of slowness of thought processes ( bradyphrenia ) , a magnetic gait ( decreased foot - to - floor clearance ) , and urinary frequency , if not incontinence . , the diagnosis of inph ( idiopathic normal - pressure hydrocephalus ) can be made . the great challenge for the clinician is to appreciate that , while dementia is more commonly associated with alzheimer 's disease , slowness of gait is more commonly associated with parkinson 's disease , and urinary incontinence is more commonly related to prostatic disease . however , the combination of these features  dementia , gait disorder , and incontinence  mandates a consideration of the diagnosis of inph . it is also increasingly recognized that inph can exist with only one or two of the triad components . an 89-year - old white male presented with a two - year history of worsening cognitive problems and  frozen walking . the problem in thinking was described by the patient as difficulty concentrating and just  some slowing down because i 'm getting old .  family members of this retired engineer the problem of cognition took the patient to a psychiatrist and neuropsychologist , who found him to have some mild impairment in immediate and delayed auditory memory and mild decrease in executive functioning . there was a suspicion of early alzheimer 's disease , and the patient was begun on donepezil . however , no improvement in his mental state was noted after one year , despite dose increments to maximal levels . around one year ago , the family began to notice an increase in falls that had occurred rarely before that time . the patient had a long history of osteoarthritis and complained of lumbar and bilateral hip pain . non - steroidal anti - inflammatory drugs ( nsaids ) improved the pain , but did not change the rate of falling that had reached monthly levels by the time of this evaluation . the patient states he had difficulty  getting the motor running ,  which the daughter translated as a kind of freezing while stepping in an increasingly slow manner . the exact cause for the falls was not clear , as the patient noted no pain on falling backwards six months ago , the time of a comprehensive physical exam by the patient 's family physician ( fp ) . that doctor believed the patient had some parkinsonian features , despite no evidence of a tremor , and so began the patient on carbidopa - levodopa . the dementia was felt to be mild and  not definitively alzheimer 's ,  but perhaps related to cortical atrophy noted on an initial head ct obtained by the psychiatrist . mild to moderate bilateral carotid atherosclerosis was noted on ultrasonography , but no stroke was apparent based on history , physical exam , or a new head ct . neurological consultation followed six months later , after increasing doses of carbidopa - levodopa showed no effect on the  stiffness of gait  on re - evaluation by the fp . neurological evaluation revealed the following : the patient seemed mildly disheveled and showed some urine stains in the anterior groin area of his pants . there was psychomotor slowing , decreased accuracy in number placement on drawing a clock face and a mini - mental status exam score of 25 . cranial nerves were normal , full sensation and strength was evident , and all reflexes were normal , except for the presence of a positive sucking and snout . bradykinesia with diffuse , mild rigidity of limbs and mild retropulsive tendency with a somewhat wide stance was evident ; gait was shuffling and magnetic , but symmetrical ; and there was no involuntary motion or ataxia . in analyzing a case of this type , the crux of the matter is apparent : this is a patient who falls  outside the ordinary  in the areas of geriatric dementia and movement disorders . on the other hand , lack of a response to donepezil the absence of striking memory deficits , along with largely in tact orientation , naming , and visuospatial skills , supports the fact the patient does not have ad . because there are some memory deficits and attentional issues , however , ad must still be considered ; a more detailed analysis , such as more focused hippocampal imaging via brain mri and positron emission tomography ( pet ) scans , cerebral spinal fluid ( csf ) analysis for beta - amyloid1 - 42 and tau proteins might well be helpful in ruling out ad . one would also argue for a more detailed depression inventory via added neuropsychological testing , such as the minnesota multiphasic personality inventory ( mmpi ) . this senior is not on side - effect - laden medication , which rules out that common cause of impaired cognition . beyond the possibilities of masked or atypical presentations for mental status aberrations is the issue of his bradykinesia , rigidity , postural instability , and absence of tremor . indeed , this could be parkinson 's disease , but the lack of response to carbidopa - levodopa strongly argues against it . dementia due to pd often occurs late in the disease , so that prior to the carbidopa - levodopa failure , a pd dementia was a consideration . vascular parkinsonism is not suggested , based on the symmetrical exam and a ct that reveals no infarction . binswanger 's disease is ruled out with a ct that shows no significant white matter disease that is the signature finding of that vasculopathy . such a  lacunar state  could induce a short - stepped gait and subcortical dementia . although the axial difficulties in the absence of tremor are very consistent with progressive supranuclear palsy , the absence of eye movement limitations effectively rules out that diagnosis . additionally , there is no history of dementia pugilistica or evidence of this condition on the imaging study results . corticobasilar degeneration and multisystem atrophy , both of which can reveal such parkinsonism , are not suggested , based upon the absence of more striking higher cortical dysfunction noted in the former and autonomic difficulties classically found in the latter [ 13 ] . certainly , an 89-year - old could have an orthopedic condition to explain the gait disorder , but in this patient , the lack of an antalgic gait argues against a painful arthropathy as the cause for falling . neurogenic claudication typical of spinal stenosis is not implicated , but such a lumbar condition is not ruled out . there is no large - fiber , neuropathy / steppage gait problem such as that seen in vitamin b12 deficiency or in neurosyphilis . the latter disorder , incredibly diverse phenomenologically , can not be ruled out completely at this point . what may be indifference to incontinence is disturbing in this case , because it implies there may be advancing deficits in judgment characteristic of a frontal lobe or subfrontal derangement . in this brain mri : moderate diffuse ventriculomegaly , mild cortical atrophy ( both worse compared to the first head ct performed one year ago ) , no infarct , some periventricular demyelination that may be age related , aqueductal flow void and no hippocampal atrophy ( figures 1 and 2 ) . neuropsychological testing : progressive frontal lobe region disease , with no depression and significant worsening in attentiveness and judgment ; minor immediate and delayed memory errors , unchanged from initial testing . note moderately enlarged ventricles ( arrows show dilated frontal and posterior horns ) ; normal volume of brain parenchyma ; hypointensity in the third ventricle signifies turbulent flow of csf . mildly enlarged ventricles ; brain tissue atrophy characterized by increased white rippling around the periphery of the cortex , signifying an increased volume of csf in subarachnoid space around atrophic brain . the patient has the triad of dementia , gait dysfunction , and incontinence with evidence for disease progression over two years [ 1 , 4 , 5 ] . typically , obliviousness to incontinence appears in advanced dementia patients , but the apparent anosognosia regarding incontinence can occur with any cognitive deficit . stretching of more central frontal lobe - white matter fibers explains the impact not only on thinking , but also on gait and continence in inph patients . whereas the diagnosis , based upon clinical and lab results , is most consistent with inph , it is reasonable at this time to review in greater detail the imaging studies used to confirm this diagnosis . the evans index is a measure reflecting ventricular size to cranial diameter . in this case , it would be expected that it is greater than 0.3 , which formally confirms ventriculomegaly . the periventricular halo noted on mri in this patient has been associated with leukoareosis seen in hydrocephalus , including that of inph . however , like the aqueductal flow void ( arising from a signal artifact created by hyperdynamic csf flow through the cerebral aqueduct ) also noted in this case , the inph diagnosis is supported , but not confirmed , via these findings . likewise , although spect , pet , and nuclear cisternography may be abnormal in inph , 100- percent certainty regarding inph can not be made , based on such studies . the critical question at this point is : given the great likelihood of inph in this patient , will a ventriculoperitoneal or ventriculoatrial shunt be effective in reducing the signs and symptoms of the condition ? in this patient , as in most , a less - than - severe dementia is a good prognostic feature . predominant gait difficulty with mild or absent dementia is a good prognostic sign for shunt success . it has been reported that the best indicator for shunt responsiveness was the presence of the complete triad , with those showing a 61.2-percent rate of improvement in all three and a 35.4-percent complication rate , mostly reversible and typically including subdural hygroma , subdural hematoma , or shunt infection . beyond the clinical presentation , ways to predict a positive response to shunting include a large volume lumbar tap test ( assess the gait prior to the tap , remove 30cc of csf , and then quickly re - assess for gait improvement , though guidelines argue not to exclude candidates based on a negative tap test ) and external lumbar drainage ( eld ) ( 4872 hours of 10cc / hr csf drainage in a special monitored setting , during which gait is frequently re - evaluated to confirm ongoing efficacy of a shunt ) . eld is helpful in identifying patients who would more likely benefit from a shunt and who have a negative tap test , i.e. , a substantial subgroup improves with eld and not with the tap test [ 9 , 10 ] . bilateral subdural hygromas . opening pressure ( op ) determination in inph is similar to those found in normals ( 122 mm + 34 mm h2o ) though the range is somewhat wider in inph.11 csf op measurement may be most useful in identifying hydrocephalic conditions ( such as secondary hydrocephalus due to a subarachnoid hemorrhage or aqueductal stenosis ) other than inph , particularly when the op is elevated above 245 mm . op determinations have mostly diagnostic value in suggesting a non - communicating hydrocephalus . once defined in inph levels , however , csf op does not influence prognosis significantly . similarly , the value of csf ro or impedance of flow offered by the csf absorption pathways is not clearly helpful in shunt responsiveness predictions . finally , this patient had high flow velocities through the aqueduct . despite this characteristic inph result , no statistically significant relationship between an aqueductal flow void sign and responsiveness to shunting has been consistently reported . after a positive gait response to the lumbar tap test , the patient underwent ventriculoperitoneal shunting without perioperative complications . the patient showed significant clinical improvement  mental improvement occurring earlier than the restoration of proper gait without falls and urinary control . the triad of gait disturbance , dementia , and urinary urgency is kind of pathognomonic for inph and should alert the physician for such a diagnosis . the normal csf op and the presence of hydrocephalus in brain imaging is confirmatory diagnosis for inph . identifying and treating patients at this early stage , before the emergence of cognitive impairment or urinary incontinence , result in good outcome . inph is a treatable disorder , especially when treatment is started early in the course of the disease . in analyzing a case of this type , the crux of the matter is apparent : this is a patient who falls  outside the ordinary  in the areas of geriatric dementia and movement disorders . on the other hand , lack of a response to donepezil the absence of striking memory deficits , along with largely in tact orientation , naming , and visuospatial skills , supports the fact the patient does not have ad . because there are some memory deficits and attentional issues , however , ad must still be considered ; a more detailed analysis , such as more focused hippocampal imaging via brain mri and positron emission tomography ( pet ) scans , cerebral spinal fluid ( csf ) analysis for beta - amyloid1 - 42 and tau proteins might well be helpful in ruling out ad . one would also argue for a more detailed depression inventory via added neuropsychological testing , such as the minnesota multiphasic personality inventory ( mmpi ) . this senior is not on side - effect - laden medication , which rules out that common cause of impaired cognition . beyond the possibilities of masked or atypical presentations for mental status aberrations is the issue of his bradykinesia , rigidity , postural instability , and absence of tremor . indeed , this could be parkinson 's disease , but the lack of response to carbidopa - levodopa strongly argues against it . dementia due to pd often occurs late in the disease , so that prior to the carbidopa - levodopa failure , a pd dementia was a consideration . vascular parkinsonism is not suggested , based on the symmetrical exam and a ct that reveals no infarction . binswanger 's disease is ruled out with a ct that shows no significant white matter disease that is the signature finding of that vasculopathy . such a  lacunar state  could induce a short - stepped gait and subcortical dementia . although the axial difficulties in the absence of tremor are very consistent with progressive supranuclear palsy , the absence of eye movement limitations effectively rules out that diagnosis . additionally , there is no history of dementia pugilistica or evidence of this condition on the imaging study results . corticobasilar degeneration and multisystem atrophy , both of which can reveal such parkinsonism , are not suggested , based upon the absence of more striking higher cortical dysfunction noted in the former and autonomic difficulties classically found in the latter [ 13 ] . certainly , an 89-year - old could have an orthopedic condition to explain the gait disorder , but in this patient , the lack of an antalgic gait argues against a painful arthropathy as the cause for falling . neurogenic claudication typical of spinal stenosis is not implicated , but such a lumbar condition is not ruled out . there is no large - fiber , neuropathy / steppage gait problem such as that seen in vitamin b12 deficiency or in neurosyphilis . the latter disorder , incredibly diverse phenomenologically , can not be ruled out completely at this point . what may be indifference to incontinence is disturbing in this case , because it implies there may be advancing deficits in judgment characteristic of a frontal lobe or subfrontal derangement . in this brain mri : moderate diffuse ventriculomegaly , mild cortical atrophy ( both worse compared to the first head ct performed one year ago ) , no infarct , some periventricular demyelination that may be age related , aqueductal flow void and no hippocampal atrophy ( figures 1 and 2 ) . neuropsychological testing : progressive frontal lobe region disease , with no depression and significant worsening in attentiveness and judgment ; minor immediate and delayed memory errors , unchanged from initial testing . note moderately enlarged ventricles ( arrows show dilated frontal and posterior horns ) ; normal volume of brain parenchyma ; hypointensity in the third ventricle signifies turbulent flow of csf . mildly enlarged ventricles ; brain tissue atrophy characterized by increased white rippling around the periphery of the cortex , signifying an increased volume of csf in subarachnoid space around atrophic brain . the patient has the triad of dementia , gait dysfunction , and incontinence with evidence for disease progression over two years [ 1 , 4 , 5 ] . typically , obliviousness to incontinence appears in advanced dementia patients , but the apparent anosognosia regarding incontinence can occur with any cognitive deficit . stretching of more central frontal lobe - white matter fibers explains the impact not only on thinking , but also on gait and continence in inph patients . whereas the diagnosis , based upon clinical and lab results , is most consistent with inph , it is reasonable at this time to review in greater detail the imaging studies used to confirm this diagnosis . the evans index is a measure reflecting ventricular size to cranial diameter . in this case , it would be expected that it is greater than 0.3 , which formally confirms ventriculomegaly . the periventricular halo noted on mri in this patient has been associated with leukoareosis seen in hydrocephalus , including that of inph . however , like the aqueductal flow void ( arising from a signal artifact created by hyperdynamic csf flow through the cerebral aqueduct ) also noted in this case , the inph diagnosis is supported , but not confirmed , via these findings . likewise , although spect , pet , and nuclear cisternography may be abnormal in inph , 100- percent certainty regarding inph can not be made , based on such studies . the critical question at this point is : given the great likelihood of inph in this patient , will a ventriculoperitoneal or ventriculoatrial shunt be effective in reducing the signs and symptoms of the condition ? in this patient , as in most , a less - than - severe dementia is a good prognostic feature . predominant gait difficulty with mild or absent dementia is a good prognostic sign for shunt success . it has been reported that the best indicator for shunt responsiveness was the presence of the complete triad , with those showing a 61.2-percent rate of improvement in all three and a 35.4-percent complication rate , mostly reversible and typically including subdural hygroma , subdural hematoma , or shunt infection . beyond the clinical presentation , ways to predict a positive response to shunting include a large volume lumbar tap test ( assess the gait prior to the tap , remove 30cc of csf , and then quickly re - assess for gait improvement , though guidelines argue not to exclude candidates based on a negative tap test ) and external lumbar drainage ( eld ) ( 4872 hours of 10cc / hr csf drainage in a special monitored setting , during which gait is frequently re - evaluated to confirm ongoing efficacy of a shunt ) . eld is helpful in identifying patients who would more likely benefit from a shunt and who have a negative tap test , i.e. , a substantial subgroup improves with eld and not with the tap test [ 9 , 10 ] . opening pressure ( op ) determination in inph is similar to those found in normals ( 122 mm + 34 mm h2o ) though the range is somewhat wider in inph.11 csf op measurement may be most useful in identifying hydrocephalic conditions ( such as secondary hydrocephalus due to a subarachnoid hemorrhage or aqueductal stenosis ) other than inph , particularly when the op is elevated above 245 mm . op determinations have mostly diagnostic value in suggesting a non - communicating hydrocephalus . once defined in inph levels , however , csf op does not influence prognosis significantly . similarly , the value of csf ro or impedance of flow offered by the csf absorption pathways is not clearly helpful in shunt responsiveness predictions . finally , this patient had high flow velocities through the aqueduct . despite this characteristic inph result , no statistically significant relationship between an aqueductal flow void sign and responsiveness to shunting has been consistently reported . after a positive gait response to the lumbar tap test the patient showed significant clinical improvement  mental improvement occurring earlier than the restoration of proper gait without falls and urinary control . the triad of gait disturbance , dementia , and urinary urgency is kind of pathognomonic for inph and should alert the physician for such a diagnosis . the normal csf op and the presence of hydrocephalus in brain imaging is confirmatory diagnosis for inph . identifying and treating patients at this early stage , before the emergence of cognitive impairment or urinary incontinence , result in good outcome . inph is a treatable disorder , especially when treatment is started early in the course of the disease .
an 89-year - old white male presented with memory impairment , slowness in responsiveness , and frequent falls over a two - year duration . 
 six months earlier , the patient was believed to have had a  dementia with parkinsonian features ,  but showed no response to incrementing doses of both donepezil and carbidopa - levodopa . 
 urinary urgency was believed to have been due to prostate hypertrophy . a head ct with contrast revealed moderate ventriculomegaly in the setting of mild diffuse cortical 
 atrophy . 
 a diagnosis of idiopathic normal - pressure hydrocephalus ( inph ) was made .