Helen S. Cohen - US grants

Recent evidence in the literature shows that the vestibular system can be modified, or habituated, with repeated presentation of a stimulus. This concept may be applied to the clinical problem of vertigo caused by vestibular neurotomy, the surgical procedure used to remove an acoustic neuroma. Excision of the vestibular nerve causes sere postoperative vertigo, impaired oculomotor control, and disequilibrium. These symptoms, particularly the vertigo and disequilibrium, are extremely disabling, although they eventually subside in most patients. Descriptive papers in the literature report the use of although they eventually subside in most patients. Descriptive papers in the literature report the use of habituating exercises to reduce the vertigo and disequilibrium caused by chronic vestibular disorders, but little research data supports their efficacy. No studies to date have addressed the rehabilitation of acutely postoperative vestibular neurectomy patients. Study of these patients would provide a well-controlled clinical model of habituation in the impaired vestibular system, and would provide some information about potentially beneficial rehabilitation procedures that can be given without the use of medication. This study, will examine the efficacy of a structured, postoperative, beside exercise program in reducing vertigo and improving postural and oculomotor control. The study will test the hypothesis that a graded exercise program given during the first 5 days after surgery will relieve the postoperative symptoms and hasten the normalization of function. Specific aims include determining rate and amount of recovery after surgery, determining the efficacy of postsurgical in-patient rehabilitation, and determining which preoperative tests best predict postoperative recovery. Subjects will be tested on seven different occasions: (1) preoperatively, in the laboratory with caloric irrigation, harmonic acceleration and other oculomotor tests, and tests of head stability, dynamic posture, gait, independence in performing activities of daily living, and intensity of vertigo; (2-5) postoperatively, at discharge, in the laboratory, on all measures examined preoperatively; (7) postoperatively, four weeks after discharge, in the laboratory, on all measures, again. Two treatment groups will be used. Half the subjects will receive equal attention bedside, without exercises.

Vestibular disorders cause vertigo and disequilibrium, which may be accompanied by malaise, inactivity, and decreased independence in activities of daily living, at tremendous cost to society. Among the few treatment options, surgery is not indicated in most cases, and medication may be contraindicated or in effective in the long term. The use of repetitive head movement exercises to reduce the vertigo and disequilibrium has become popular but little empirical data support the effectiveness of these exercise programs, and extraneous variables confound many of the reports. Well-controlled studies of exercise paradigms for treating the sequelae of vestibular impairments are needed to develop efficacious, cost-effective treatments for these problems without the use of medication or surgery. By systematically varying the treatment parameters, this study will determine the effectiveness of structured programs of head movement exercises in reducing vertigo, improving postural control, and increasing independence in performing essential daily life tasks. Subjects diagnosed with one of two chronic peripheral vestibular impairments - either chronic vestibulopathy or labyrinthine concussion - will be tested for the short- and long-term effects of five different conditions: 1) spontaneous recovery without intervention, 2) home exercise program without increased attention, 3) home program with increased attention, 4) weekly out-patient head exercise program plus home program, and 5) weekly out-patient head exercise program without home program to control for the effects of increased attention and increased activity level. The home program will include repetitive pitch, roll, and yaw head movements; the attention will be a weekly telephone call. The out-patient programs will be given in the laboratory by a physical therapist and will include repetitive exercises that stimulate head movements and visual/vestibular interaction. All subjects will have been diagnosed with either a peripheral vestibulopathy or a labyrinthine concussion. All subjects will have had vertigo for at least three months prior to referral to the study; no subjects will take vestibular-suppressant medications while participating in the study. The specific aims will be to: 1) determine the contribution of the following factors to recovery: spontaneous compensation without intervention, increased attention, and head movement exercises, 2) determine if treatment effects are retained after treatment ceases, and 3) determine if subjects with two different diagnoses (chronic vestibulopathy and labyrinthine concussion) respond differently to treatment. Subjects will be tested five times: the pre-test, a post-test after four weeks of treatment, and subsequent tests one month, two months, and three months after the end of treatment. The measures will be posturography scores, attacks of vertigo per day, intensity of vertigo, and level of independence in activities of daily living.

DESCRIPTION (provided by applicant): Benign paroxysmal positional vertigo is the most common vestibular disorder. Patients with this problem complain of vertigo elicited by up/down head rotations. It can be disorienting, somewhat disabling, and can interfere with sleep and driving skills. In the previous funding period we tested the overall effectiveness of several standard treatments and some common variations, but did not examine the differences among diagnostic subgroups. In this funding period, we will test the effectiveness of passive repositioning maneuvers and repositioning exercises for canalithiasis vs. cupulolithiasis. Since lateral canal involvement is a common variant, we will study the prevalence and response to treatment of people posterior canal plus lateral canal involvement. We have evidence from the previous funding period that suggests this population may have an unusually high number of individuals with co-morbid rhinosinusitis, so we will study this issue more closely. Therefore, this study will have the following specific aims: 1. Determine the effectiveness of Epley's canalith repositioning maneuver and Semont's libertory maneuver in treating canalithiasis and cupulolithiasis, the two possible subcategories of BPPV. 2. Determine if use of the passive repositioning maneuvers in combination with one week of the Brandt & Daroff exercise at home is more effective for treating P-BPPV than the maneuvers alone. 3. Determine the influence of lateral canal BPPV. A) Determine the prevalence of L-BPPV in P-BPPV patients. B) In P-BPPV patients who also have L-BPPV, determine if treatment with the Semont maneuver followed by log rolling is as effective as use of just the Semont maneuver. 4. Determine the influence of rhinosinusitis. A) Determine the prevalence of rhinosinusitis in patients with BPPV. B) Determine if the presence of rhinosinusitis affects severity of symptoms or response to treatment.

Exposure to microgravity causes short- and long-term changes in sensorimotor integration as indicated by astronauts' clinically significant decrements in performance of tasks that require sensorimotor integration shortly after landing. These deficits have potentially serious consequences for crew safety at landing and for crew efficiency in the first few days after landing, either on Earth or some other planetary surface. Likewise, patients with vestibularly-related balance impairments have functional limitations in tasks requiring good dynamic balance and visual acuity, with significant implications for their safety and for their quality of life. Thus countermeasures, i.e., rehabilitative treatments, are needed for both populations, to facilitate acquisition or re-acquisition of adaptive motor strategies in response to sensorimotor challenges. This study will test a rehabilitation approach for maintaining or rapidly reaquiring terrestrial strategies for dynamic balance and sensorimotor integration after exposure to microgravity and for acquiring new movement strategies after loss or impairment of vestibular function. The study will have the following specific aims: 1) Determine the effectiveness of sensorimotor practice variability for transfer of the ability to "learn to learn" adaptive sensorimotor strategies under different conditions of visual/vestibular rearrangement. We will also determine the changes in head-trunk coordination and lower limb kinematics during gait and determine which kinematic patterns are most compatible with successful motor performance. We hypothesize that subjects trained with variable practice on either visual rearrangement (induced with three sets of experimental lenses) or exercise (with treadmill walking at two speeds) will have significantly better scores than subjects trained in the constant practice groups when post-tested on transfer trials using a fourth set of lenses and a third speed. We further hypothesize that subjects trained with variable practice on both visual rearrangement and exercise will have significantly better scores than subjects in constant practice groups and subjects in groups given variable practice on only one parameter. 2) Determine the effectiveness of sensorimotor practice variability for retention of the ability to "learn to learn" adaptive sensorimotor strategies under different conditions of visual/ vestibular rearrangement. We hypothesize that on retention trials given one month after the post-test transfer trials in Specific Aim 1, subjects trained with variable practice on either visual rearrangement or exercise will have significantly better scores than subjects trained in the constant practice groups; furthermore, subjects trained on variable practice on both parameters will have significantly better scores than subjects in constant practice groups and subjects in groups given variable practice on only one parameter.

? DESCRIPTION (provided by applicant): The long-term goal of this study is to develop valid and reliable tests for screening people for vestibular (inner ear) disorders, so that those tests can be used in studies of the American population to determine the frequency of vestibular disorders in the general population. We also expect that these tests will be useful in nursing homes and other facilities with limited resources for testing, and at landing sites for astronauts after returning from long duration space flight. In Specific Aim 1 we will complete test development, including developing age-appropriate norms for a test of standing balance, and we will determine which tests best distinguish healthy controls from people with known vestibular disorders. In Specific Aim 2 we will test the test battery, to determine how well the tet battery predicts who in the general population has a vestibular impairment. Participants will be given the test battery and then will be tested in the diagnostic laboratory with the standard battery of objective diagnostic tests. Using the new test battery in Specific Aim 2A we will screen people recruited from clinics at Baylor College of Medicine. The screening environment at Baylor College of Medicine will be well-controlled so that we will be able to work out any technical bugs in the system. Using the new screening battery we will also test people at a distant site, the Washington, DC site of the Women's Interagency HIV Study (WIHS). The WIHS includes participants who have HIV or AIDS and participants who are age-matched healthy controls. At this site we will have less control over the screening environment but will work with an excellent, well-established epidemiologic team to determine not only how well the tests predict results from the diagnostic laboratory but also how easy the battery is for staff to administer. Additional benefits of testing the WIHS cohort, men recruited from the Infectious Disease clinic at Georgetown University Medical Center, and men from the community who do not have HIV/AIDS, will be the ability to learn more about the effects of HIV/AIDS on vestibular disorders in middle-aged and early-elderly people who also represent underserved populations that are rarely, if ever, invited to participate in research on vestibular and balance disorders, ie., homosexual/ bisexual men and low-income, minority women in the WIHS. Because these tests may also be used in community health centers where homosexual/ bisexual men and low income, minority women with HIV/AIDS often receive health care developing these tests may improve the quality of care available to those subpopulations.