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Helen S Cohen

Publications and source records attributed to Helen S Cohen.

At least 19 recordsLinked to original sources
PubMed2006

Long-term monitoring of gait in Parkinson's disease.

A new system for long-term monitoring of gait in Parkinson's disease (PD) has been developed and validated. The characteristics of every stride taken over 10-h epochs were acquired using a lightweight ankle-mounted sensor array that transmitted data wirelessly to a small pocket PC at a rate of 100 Hz. Stride was calculated from the vertical linear acceleration and pitch angular velocity of the leg with an accuracy of 5 cm. Results from PD patients (5) demonstrate the effectiveness of long-term monitoring of gait in a natural environment. The small, variable stride length characteristic of Parkinsonian gait, and fluctuations of efficacy associated with levodopa therapy, such as delayed onset, wearing off, and the 'off/on' effect, could reliably be detected from long-term changes in stride length.

Adult↗
PubMed2006

Modeling locomotor dysfunction following spaceflight with Galvanic vestibular stimulation.

In this study locomotor and gaze dysfunction commonly observed in astronauts following spaceflight were modeled using two Galvanic vestibular stimulation (GVS) paradigms: (1) pseudorandom, and (2) head-coupled (proportional to the summed vertical linear acceleration and yaw angular velocity obtained from a head-mounted Inertial Measurement Unit). Locomotor and gaze function during GVS were assessed by tests previously used to evaluate post-flight astronaut performance; dynamic visual acuity (DVA) during treadmill locomotion at 80 m/min, and navigation of an obstacle course. During treadmill locomotion with pseudorandom GVS there was a 12% decrease in coherence between head pitch and vertical translation at the step frequency relative to the no GVS condition, which was not significantly different to the 15% decrease in coherence observed in astronauts following shuttle missions. This disruption in head stabilization likely resulted in a decrease in DVA equivalent to the reduction in acuity observed in astronauts 6 days after return from extended missions aboard the International Space Station (ISS). There were significant increases in time-to-completion of the obstacle course during both pseudorandom (21%) and head-coupled (14%) GVS, equivalent to an ISS astronaut 5 days post-landing. An attempt to suppress head movement was evident during both pseudorandom and head-coupled GVS while negotiating the obstacle course, with a 20 and 16%, decrease in head pitch and yaw velocity, respectively. The results of this study demonstrate that pseudorandom GVS generates many of the salient features of post-flight locomotor dysfunction observed in astronauts following short and long duration missions. An ambulatory GVS system may prove a useful adjunct to the current pre-flight astronaut training regimen.

Adult↗
PubMed2006

Disability and rehabilitation in the dizzy patient.

PURPOSE OF REVIEW: This review focuses on prospective studies of vertigo and balance therapy in the past 3 years, including advances in vertigo-habituation exercises for adults, pediatric intervention, and virtual reality techniques, and, in more depth, the literature pertinent to driving motor vehicles. RECENT FINDINGS: Increased support has been generated for the efficacy of a minimal, home-based vertigo-habituation program for adults with peripheral vestibular disorders. Vestibular rehabilitation has been shown to be associated with improvements in independence and dynamic visual acuity. Community-based vestibular rehabilitation has been shown to be efficacious for selected patients, after careful screening, when trained personnel provide intervention. Vestibular rehabilitation has been incorporated into the rehabilitation program for head-injured military personnel who will be returned to duty, and multifactorial balance rehabilitation has been shown to be useful for children with hearing and balance impairments. Virtual reality techniques have made significant advances, so immersive environments have potential for rehabilitation for patients with vestibular disorders and for developing training regimens for astronauts to ameliorate some effects of exposure to microgravity. Driving skill, in general, is affected by use of benzodiazepines. For many patients with vestibular impairments driving is a particularly problematic activity of daily living. SUMMARY: Progress has been made in studies of acute care, community-based, and pediatric vestibular rehabilitation. Work on simulator-based paradigms has moved toward readiness for implementation. Studies of driving have provided some insight into the problems of these patients. More work remains to be done on all of these problems.

Activities of Daily Living↗
PubMed2006

Active head movements facilitate compensation for effects of prism displacement on dynamic gait.

STUDY DESIGN: Four groups, between-subjects study. OBJECTIVES: To investigate the effects of exercise on adaptation of normal subjects who had been artificially spatially disoriented. BACKGROUND: Many patients referred for rehabilitation experience sensory changes, due to age or disease processes, and these changes affect motor skill. The best way to train patients to adapt to these changes and to improve their sensorimotor skills is unclear. Using normal subjects, we tested the hypothesis that active, planned head movement is needed to adapt to modified visual input. METHODS AND MEASURES: Eighty male and female subjects who had normal balance on computerized dynamic posturography (CDP) and the dynamic gait index (DGI), were randomly assigned to four groups. All groups donned diagonally shift lenses and were again assessed with CDP and DGI. The four groups were then treated for 20 min. Group 1 (control group) viewed a video, Group 2 performed exercise that involved translating the entire body through space, but without separate, volitional head movement, Group 3 performed exercises which all incorporated volitional, planned head rotations, and Group 4 performed exercises that involved translating the body (as in Group 2) and incorporated volitional, planned head motion (as in Group 3). All subjects were post-tested with CDP and DGI, lenses were removed, and subjects were retested again with CDP and DGI. RESULTS: The groups did not differ significantly on CDP scores but Groups 3 and 4 had significantly better DGI scores than Groups 1 and 2. CONCLUSIONS: Active head movement that is specifically planned as part of the exercise is more effective than passive attention or head movements that are not consciously planned, for adapting to sensorimotor change when it incorporates active use of the changed sensory modality, in this case head motion.

Adaptation, Physiological↗
PubMed2005

Effectiveness of treatments for benign paroxysmal positional vertigo of the posterior canal.

OBJECTIVE: To determine which common, nonpharmacological, nonsurgical treatments are most effective for treatment of benign paroxysmal positional vertigo (BPPV). STUDY DESIGN: Prospective, randomized, sham-controlled. PATIENTS: Patients (n = 124) with BPPV of the posterior semicircular canal. SETTING: Tertiary care center. INTERVENTIONS: Random assignment to one of five groups: modified canalith repositioning maneuver (CRP), modified liberatory maneuver (LM), sham maneuver, Brandt and Daroff's exercise, and vertigo habituation exercises. Subjects received a standard educational lecture about BPPV and the purpose of the intervention. No vestibular-suppressant medication or special instructions for head positioning were used. Post-tests were given at 1 week after treatment and at approximately 3 months and 6 months later. MAIN OUTCOME MEASURES: Vertigo intensity and frequency. RESULTS: Multilevel analyses showed that vertigo decreased significantly after LM, CRP, and Brandt-Daroff exercise; those three groups did not differ significantly. The habituation group did not differ from sham, Brandt-Daroff, LM, or CRP groups. Changes in scores were maintained throughout the 6-month follow-up period. CONCLUSION: LM, CRP, and exercises are all effective interventions; patient education plus the sham maneuver, however, had some beneficial effect. These results support two possible mechanisms of BPPV: displaced otoconia and a neural mechanism affecting interpretation of semicircular canal signals.

Adult↗
PubMed2005

Obstacle avoidance in novel visual environments improved by variable practice training.

Motor performance on simple tasks improves after training in variable practice. We asked if locomotor skill during an obstacle-avoidance task in a novel sensorimotor environment improved through training in variable practice on other complex tasks. 40 normal adults practiced gross motor skills while wearing either sham lenses, one of several visual distortion lens (constant practice), or three different visual distortion lenses (variable practice). Posttests on obstacle avoidance with novel lenses showed significantly better scores with variable practice and one of the constant groups vs sham lenses. Constant and variable practice groups did not differ. Thus, performance in a novel environment improves after training on similar type novelty, even when practice and test conditions differ. Constant practice was effective only if the subjects used the lens efficacious in training. Variable practice increases the likelihood of efficacious training when adaptive performance is required in a novel environment.

Adult↗
PubMed2004

Decreased ataxia and improved balance after vestibular rehabilitation.

OBJECTIVES: To determine the effects of vestibular rehabilitation on gait ataxia and balance. SETTING: Tertiary care center. Study design Subjects were patients with chronic vertigo due to peripheral vestibular impairments, referred for vestibular rehabilitation. They were assessed on the Timed Up and Go test, ataxia during a path integration test, computerized dynamic posturography, level of vertigo, independence in activities of daily living, and psychological locus of control. They were randomly assigned to three home program treatment groups. RESULTS: Ataxia decreased significantly, and posturography scores and time to perform Timed Up and Go improved significantly, for all subjects. Improvements were significantly related to scores on the ambulation subtest of the Vestibular Disorders Activities of Daily Living Scale, decreases in vertigo, and increases in locus of control. CONCLUSIONS: For many patients, a simple home program of vestibular habituation head movement exercises is related to reduced symptoms of imbalance during stance and gait.

Activities of Daily Living↗
PubMed2004

Side-lying as an alternative to the Dix-Hallpike test of the posterior canal.

OBJECTIVE: Limitations in passive or active range of motion preclude testing some patients suspected of benign paroxysmal positional vertigo of the posterior semicircular canal (BPPV) with the Dix-Hallpike maneuver. The goal of this study was to determine if an alternative test, brisk side-lying with the nose turned 45 degrees away from the tested side, yields the same results as the Dix-Hallpike maneuver. STUDY DESIGN: Prospective, within-groups. SETTING: Diagnostic laboratory at a tertiary care center. PATIENTS: The 61 patients, seen before their physicians had determined their diagnoses, were all referred by their physicians for objective diagnostic tests. All subjects complained of vertigo elicited by up or down rotations of the head or turning over in bed, often provocative positions for BPPV. METHODS: Results from the Dix-Hallpike maneuver and side-lying maneuver were compared. Group 1 was tested with the Dix-Hallpike maneuver followed up by side-lying; Group 2 was tested in reverse order. MAIN OUTCOME MEASURES: Slow-phase eye velocity of nystagmus. RESULTS: With the groups collapsed to eliminate possible order effects, no significant differences were found between the tests. Significantly more subjects had no response to testing than minimal or stronger responses. CONCLUSIONS: Side-lying is a valid alternative test to the Dix-Hallpike maneuver, which could be useful when range-of-motion limitations or other problems preclude use of the Dix-Hallpike maneuver.

Adult↗
PubMed2004

Benign paroxysmal positional vertigo and comorbid conditions.

PURPOSE: To determine the prevalence of comorbid disease in patients with benign paroxysmal positional vertigo (BPPV) and the relationship of comorbid disease to symptoms of vertigo, disequilibrium, and anxiety. PROCEDURES: Patients who had posterior semicircular canal BPPV and who had been referred for vestibular rehabilitation at a tertiary care center completed a health status questionnaire and the Vertigo Symptom Scale, answered questions about level of vertigo, and were tested on computerized dynamic posturography. RESULTS: Subjects had high rates of diabetes, mild head trauma, and probable sinus disease. Balance was generally impaired, worse in diabetics and subjects with significant vestibular weakness. Subjects who smoked or had had mild head trauma had higher levels of anxiety. CONCLUSIONS: Comorbid conditions, particularly diabetes, mild head trauma, and sinus disease, are unusually prevalent in BPPV patients. Message: Patients with comorbid disease are at risk for having increased vertigo, anxiety, and disequilibrium compared to other patients.

Adult↗
PubMed2004

Changes in a repetitive head movement task after vestibular rehabilitation.

OBJECTIVE: Many papers describe vestibular rehabilitation programmes to reduce vertigo and disequilibrium caused by peripheral vestibular disorders, but few studies have assessed performance on purposeful activities. This study determined if performance on a purposeful activity improves after vestibular rehabilitation exercises, and if the speed of treatment exercises influences performance. SETTING: Medical school practice; tertiary care facility. SUBJECTS: Fifty-three patients with chronic vertigo caused by peripheral vestibular weakness. INTERVENTIONS: Subjects performed vestibular rehabilitation head movement exercises to habituate vertigo, in either slow or rapid movement groups. MAIN MEASURES: Time to perform a repetitive head movement task and intensity of vertigo elicited by that task, questionnaires about independence in activities of daily living and reported usual intensity of vertigo. RESULTS: Both groups significantly decreased the time to perform the task and the intensity of elicited vertigo. Results were related to improved independence in activities of daily living and to decreased vertigo. CONCLUSION: Vertigo decreases and speed of head movement improved after a programme of vestibular rehabilitation, regardless of speed of treatment exercises. A simple purposeful activity can be useful to evaluate improvements after vestibular rehabilitation.

Adolescent↗
PubMed2003

Driving disability and dizziness.

PROBLEM: People with dizziness caused by vestibular (i.e., inner ear) disorders complain of difficulty driving. Physicians occasionally warn their patients with vestibular disorders not to drive. Few studies have asked patients about their driving performance, so little data are available. METHOD: Using the Driving Habits Questionnaire, the authors did structured interviews with people with several different vestibular disorders and with normal subjects. The self-reported crash rate and rate of citations for moving violations did not differ between the subject groups. RESULTS: Patients report reduced driving skills, particularly in situations when visual information is reduced, rapid head movements are used, and specific path integration or spatial navigation skills are needed.

Adult↗
PubMed2003

Increased independence and decreased vertigo after vestibular rehabilitation.

OBJECTIVE: We sought to determine the effectiveness in decreasing some symptoms, such as vertigo, and increasing performance of daily life skills after vestibular rehabilitation. STUDY DESIGN AND SETTING: Patients who had chronic vertigo due to peripheral vestibular impairments were seen at a tertiary care center. They were referred for vestibular rehabilitation and were assessed on vertigo intensity and frequency with the use of the Vertigo Symptom Scale, the Vertigo Handicap Questionnaire, the Vestibular Disorders Activities of Daily Living Scale, and the Dizziness Handicap Inventory. They were then randomly assigned to 1 of 3 home program treatment groups. RESULTS: Vertigo decreased and independence in activities of daily living improved significantly. Improvement was not affected by age, gender, or history of vertigo. CONCLUSION: For many patients a simple home program of vestibular habituation head movement exercises is related to reduction in symptoms and increasing independence in activities of daily living.

Activities of Daily Living↗
PubMed2003

Update on the status of rehabilitative countermeasures to ameliorate the effects of long-duration exposure to microgravity on vestibular and sensorimotor function.

This paper is an overview of current research on development of rehabilitative countermeasures to ameliorate the effects of long-term exposure to microgravity on sensorimotor function during space flight. After many years of work we do not yet have operational countermeasures, probably for several reasons: 1) changes in the use of vestibular input are manifested in many ways, 2) due to multiple mechanisms for funding research, investigators doing related research may not coordinate their work, and 3) relatively few scientists work on this problem. The number of investigators and physicians who routinely deal with the functional problems of astronauts and the limitations of working in the space environment is tiny; the number of investigators who are therapists, and who therefore have experience and expertise in developing rehabilitation programs, is miniscule. That's the bad news. The good news is that as a group, we are little but mighty. Therefore, the entire group of investigators can plan to take a more coordinated, collaborative approach than investigators in larger fields. Also, serendipitously, individual research groups have begun approaching different rehabilitative aspects of this problem. If we make a greater effort toward a coordinated, multidimensional approach, guided by rehabilitation concepts, we will be able to provide operational sensorimotor countermeasures when they are needed.

Aerospace Medicine↗
PubMed2002

Improvements in path integration after vestibular rehabilitation.

Fifty-three subjects with peripheral, chronic vestibulopathies, who were referred for vestibular rehabilitation, were tested on a path integration task before and after doing four weeks of five times daily habituation exercises for vertigo reduction. The task involved walking over a 7.62 m path with eyes closed. Dependent measures were velocity and angle of veering from the straight ahead. At the post-test and at succeeding follow-up tests for up to six months, subjects had significant increases in velocity and significant declines in angle of veering. Length of time subjects had vertigo prior to starting rehabilitation, and speed of head movement exercises were not associated with improvements. These data support the previous finding that patients with vestibular impairments have decreased performance on this task. The data also suggest that vestibular rehabilitation, given as a simple home program, is associated with improvements in this skill.

Adult↗
PubMed2002

Factors affecting recovery after acoustic neuroma resection.

In order to determine which variables influence recovery from acoustic neuroma resection, acutely postoperative patients were divided into two groups and treated twice daily at bedside as inpatients at a tertiary care center. Treatment times were increased gradually from 5 to 30 min. Exercise subjects underwent passive and active head movements and walking with augmented head movements. Control subjects received attention without exercise. Pre- and post-tests included vertigo intensity and frequency, low-frequency vestibulo-ocular reflex (VOR), posturography and path integration. Post-tests were given at discharge and at approximately 4-week intervals for 3 months. Multilevel statistical analyses showed that neither group assignment nor age affected the outcome. All measures were abnormal at discharge but improved towards normal within 3 weeks. VOR on the unoperated side returned to normal values but on the lesioned side did not. Therefore, compensation is influenced by tumor size but not by age or early postoperative vestibular rehabilitation. Most compensation occurs within 3 weeks, probably due to central mechanisms, although some measures may not recover completely.

Adult↗
PubMedDate not supplied

Treatment variations on the Epley maneuver for benign paroxysmal positional vertigo.

PURPOSE: To determine if using more head rotation during the Epley maneuver or specific posttreatment instructions for sleeping position would affect treatment effectiveness, compared with the usual maneuver without extra instructions. MATERIALS AND METHODS: Patients with unilateral benign paroxysmal positional vertigo of the posterior semicircular canal were randomized to a standard Epley maneuver group, a group that received an additional 45 degrees head rotation during the maneuver (Augmented Epley), and a group that received instructions about sleeping position after treatment. RESULTS: Posttests from 1 week to 6 months showed no differences in vertigo intensity or frequency or responses to the Dix-Hallpike maneuver. All groups showed significant decreases in vertigo and Dix-Hallpike responses. Some subjects in each group had abnormal pretreatment scores on computerized dynamic posturography. Those subjects in the Augmented Epley group who had abnormal pretreatment posturography scores had significantly better posttreatment scores than those subjects in the Home Instruction group who had abnormal pretreatment scores. All subjects with abnormal responses, however, showed improvement. CONCLUSIONS: Although clinicians continue to give patients home instructions and to use additional head rotation during the maneuver, these variations are not essential for achieving improvement in symptoms.

Adult↗
PubMedDate not supplied

Effects of normal aging on visuo-motor plasticity.

Normal aging is associated with declines in neurologic function. Uncompensated visual and vestibular problems may have dire consequences including dangerous falls. Visuo-motor plasticity is a form of behavioral neural plasticity, which is important in the process of adapting to visual or vestibular alteration, including those changes due to pathology, pharmacotherapy, surgery or even entry into microgravity or an underwater environment. To determine the effects of aging on visuo-motor plasticity, we chose the simple and easily measured paradigm of visual-motor rearrangement created by using visual displacement prisms while throwing small balls at a target. Subjects threw balls before, during and after wearing a set of prisms which displace the visual scene by twenty degrees to the right. Data obtained during adaptation were modeled using multilevel modeling techniques for 73 subjects, aged 20 to 80 years. We found no statistically significant difference in measures of visuo-motor plasticity with advancing age. Further studies are underway examining variable practice training as a potential mechanism for enhancing this form of behavioral neural plasticity.

Adult↗