Type, dose, and outcomes of physical therapy interventions for unilateral peripheral vestibular hypofunction: protocol for a systematic review.

BACKGROUND: Unilateral peripheral vestibular hypofunction can result in symptoms of dizziness, gaze and gait instability, and impaired navigation and spatial orientation. These impairments and activity limitations may negatively impact an individual's quality of life, ability to perform activities of daily living, drive, and work. There is strong evidence supporting vestibular physical therapy for reducing symptoms, improving gaze and postural stability, and improving function in individuals with vestibular hypofunction. However, there is great variability in clinical practice with regard to the type of interventions and only weak evidence to guide optimal exercise dosage. It is important to identify the most appropriate interventions and exercise dosage to optimize and accelerate recovery of function and to decrease distress. The objective of this systematic review is to determine which interventions and which doses are most effective in decreasing dizziness or vertigo, improving postural control, and improving quality of life in adults with unilateral peripheral vestibular hypofunction. METHODS: The literature will be systematically searched using the following online databases: PubMed/MEDLINE, EMBASE, Web of Science (Science and Social Science Citation Index), Cumulative Index for Nursing and Allied Health Literature (CINAHL), and The Cochrane Library (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials [CENTRAL], Cochrane Methodology Register). The review will include randomized controlled trials (RCTs), including cluster RCTs, to assess the beneficial effects of the interventions. Assessment of methodological quality and risk of bias will be performed by two independent, blinded reviewers using the PEDro scale and Cochrane Risk of Bias version 2, respectively. The primary outcome measure will be change in self-perceived handicap related to dizziness from baseline to the end of the study, measured using the Dizziness Handicap Inventory. Other relevant outcome measures will include self-reported change in symptoms (to include severity, frequency, and duration) such as verbal or visual analog scales for dizziness. Tertiary outcome measures will include questionnaires related to disability and/or quality of life. DISCUSSION: This systematic review will identify, evaluate, and integrate the evidence on the effectiveness of physical therapy interventions for unilateral peripheral vestibular hypofunction in an adult population. We anticipate our findings may inform individualized treatment and future research. Clinical recommendations generated from this systematic review may inform vestibular physical therapy treatment of individuals with unilateral peripheral vestibular hypofunction. TRIAL REGISTRATION: In accordance with the guidelines, our systematic review protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on 06 August 2021 (registration number CRD42021266163 ). In the event of protocol amendments, the date of each amendment will be accompanied by a description of the change and the rationale.

Treatment of Vestibular Disorders (Inner Ear Balance Problems): How Does Your Physical Therapist Treat Dizziness Related to Inner Ear Balance Problems?

Dizziness is very common, but it is never normal. Dizziness can make performing daily activities, work, and walking difficult. Inner ear balance problems can make people dizzy when they turn their head, which can cause problems during walking and make people more likely to fall. Most of the time dizziness is not from a life-threatening disease. Often, dizziness is related to a problem of the vestibular (or inner ear balance) system. Vestibular disorders can be caused by infections in the ear, problems with the immune system, medications that harm the inner ear, and rarely from diabetes or stroke because of a lack of blood flow to the inner ear. Stress, poor sleep, migraine headaches, overdoing some activities, and feeling anxious or sad can increase symptoms of dizziness. Updated guidelines for the treatment of inner ear disorders are published in this issue of the Journal of Neurologic Physical Therapy. The guideline recommends which exercises are best to treat the dizziness and balance problems commonly seen with an inner ear problem.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Updated Clinical Practice Guideline From the Academy of Neurologic Physical Therapy of the American Physical Therapy Association.

BACKGROUND: Uncompensated vestibular hypofunction can result in symptoms of dizziness, imbalance, and/or oscillopsia, gaze and gait instability, and impaired navigation and spatial orientation; thus, may negatively impact an individual's quality of life, ability to perform activities of daily living, drive, and work. It is estimated that one-third of adults in the United States have vestibular dysfunction and the incidence increases with age. There is strong evidence supporting vestibular physical therapy for reducing symptoms, improving gaze and postural stability, and improving function in individuals with vestibular hypofunction. The purpose of this revised clinical practice guideline is to improve quality of care and outcomes for individuals with acute, subacute, and chronic unilateral and bilateral vestibular hypofunction by providing evidence-based recommendations regarding appropriate exercises. METHODS: These guidelines are a revision of the 2016 guidelines and involved a systematic review of the literature published since 2015 through June 2020 across 6 databases. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case-control series, and case series for human subjects, published in English. Sixty-seven articles were identified as relevant to this clinical practice guideline and critically appraised for level of evidence. RESULTS: Based on strong evidence, clinicians should offer vestibular rehabilitation to adults with unilateral and bilateral vestibular hypofunction who present with impairments, activity limitations, and participation restrictions related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) to promote gaze stability. Based on moderate to strong evidence, clinicians may offer specific exercise techniques to target identified activity limitations and participation restrictions, including virtual reality or augmented sensory feedback. Based on strong evidence and in consideration of patient preference, clinicians should offer supervised vestibular rehabilitation. Based on moderate to weak evidence, clinicians may prescribe weekly clinic visits plus a home exercise program of gaze stabilization exercises consisting of a minimum of: (1) 3 times per day for a total of at least 12 minutes daily for individuals with acute/subacute unilateral vestibular hypofunction; (2) 3 to 5 times per day for a total of at least 20 minutes daily for 4 to 6 weeks for individuals with chronic unilateral vestibular hypofunction; (3) 3 to 5 times per day for a total of 20 to 40 minutes daily for approximately 5 to 7 weeks for individuals with bilateral vestibular hypofunction. Based on moderate evidence, clinicians may prescribe static and dynamic balance exercises for a minimum of 20 minutes daily for at least 4 to 6 weeks for individuals with chronic unilateral vestibular hypofunction and, based on expert opinion, for a minimum of 6 to 9 weeks for individuals with bilateral vestibular hypofunction. Based on moderate evidence, clinicians may use achievement of primary goals, resolution of symptoms, normalized balance and vestibular function, or plateau in progress as reasons for stopping therapy. Based on moderate to strong evidence, clinicians may evaluate factors, including time from onset of symptoms, comorbidities, cognitive function, and use of medication that could modify rehabilitation outcomes. DISCUSSION: Recent evidence supports the original recommendations from the 2016 guidelines. There is strong evidence that vestibular physical therapy provides a clear and substantial benefit to individuals with unilateral and bilateral vestibular hypofunction. LIMITATIONS: The focus of the guideline was on peripheral vestibular hypofunction; thus, the recommendations of the guideline may not apply to individuals with central vestibular disorders. One criterion for study inclusion was that vestibular hypofunction was determined based on objective vestibular function tests. This guideline may not apply to individuals who report symptoms of dizziness, imbalance, and/or oscillopsia without a diagnosis of vestibular hypofunction. DISCLAIMER: These recommendations are intended as a guide to optimize rehabilitation outcomes for individuals undergoing vestibular physical therapy. The contents of this guideline were developed with support from the American Physical Therapy Association and the Academy of Neurologic Physical Therapy using a rigorous review process. The authors declared no conflict of interest and maintained editorial independence.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A369).

Factors Associated With Rehabilitation Outcomes in Patients With Unilateral Vestibular Hypofunction: A Prospective Cohort Study.

OBJECTIVE: The purpose of this study was to determine factors associated with rehabilitation outcomes following vestibular rehabilitation (VR). METHODS: In this prospective cohort study, 116 patients who completed at least 2 supervised sessions participated. Patient characteristics and comorbidities were recorded. Initial and discharge measures included symptom intensity, balance confidence, quality of life, percent of time symptoms interfere with life, perceived benefits of VR, gait speed, fall risk, visual acuity during head movement, and anxiety/depression. Intention-to-treat analyses were performed to determine outcomes at discharge. Bivariate correlations between independent (group characteristics and baseline measures) and dependent (discharge measures) variables were determined. Logistic regressions were performed to identify factors associated with whether a patient would have a normal score or meaningful change at discharge. RESULTS: There was a large effect of VR with significant improvement for the group as a whole on each outcome measure. For each outcome measure, most patients improved. Based on preliminary logistic regression, 2 patient characteristics were associated with outcome: number of therapy visits predicted meaningful improvement in gait speed, and falls after the onset of the unilateral vestibular hypofunction (UVH) predicted meaningful change in the percent of time symptoms interfered with life. Initial Activities-Specific Balance Confidence Scale (ABC) and Dynamic Gait Index scores predicted normal ABC scores at discharge, and initial ABC scores predicted recovery of Dynamic Gait Index scores. Preliminary prediction models were generated for balance confidence, impact of dizziness on life, dynamic visual acuity, gait speed, and fall risk. CONCLUSIONS: Therapists may use these findings for patient education or to determine the need for adjunct therapy, such as counseling. IMPACT: Not all people with UVH improve following VR, but there is little research examining why. This study looked at multiple factors and identified number of visits and falls after onset of UVH as patient characteristics associated with outcomes following VR; these findings will help therapists create better predictive models.

Vestibular Rehabilitation for Peripheral Vestibular Hypofunction: An Evidence-Based Clinical Practice Guideline: FROM THE AMERICAN PHYSICAL THERAPY ASSOCIATION NEUROLOGY SECTION.

BACKGROUND: Uncompensated vestibular hypofunction results in postural instability, visual blurring with head movement, and subjective complaints of dizziness and/or imbalance. We sought to answer the question, "Is vestibular exercise effective at enhancing recovery of function in people with peripheral (unilateral or bilateral) vestibular hypofunction?" METHODS: A systematic review of the literature was performed in 5 databases published after 1985 and 5 additional sources for relevant publications were searched. Article types included meta-analyses, systematic reviews, randomized controlled trials, cohort studies, case control series, and case series for human subjects, published in English. One hundred thirty-five articles were identified as relevant to this clinical practice guideline. RESULTS/DISCUSSION: Based on strong evidence and a preponderance of benefit over harm, clinicians should offer vestibular rehabilitation to persons with unilateral and bilateral vestibular hypofunction with impairments and functional limitations related to the vestibular deficit. Based on strong evidence and a preponderance of harm over benefit, clinicians should not include voluntary saccadic or smooth-pursuit eye movements in isolation (ie, without head movement) as specific exercises for gaze stability. Based on moderate evidence, clinicians may offer specific exercise techniques to target identified impairments or functional limitations. Based on moderate evidence and in consideration of patient preference, clinicians may provide supervised vestibular rehabilitation. Based on expert opinion extrapolated from the evidence, clinicians may prescribe a minimum of 3 times per day for the performance of gaze stability exercises as 1 component of a home exercise program. Based on expert opinion extrapolated from the evidence (range of supervised visits: 2-38 weeks, mean = 10 weeks), clinicians may consider providing adequate supervised vestibular rehabilitation sessions for the patient to understand the goals of the program and how to manage and progress themselves independently. As a general guide, persons without significant comorbidities that affect mobility and with acute or subacute unilateral vestibular hypofunction may need once a week supervised sessions for 2 to 3 weeks; persons with chronic unilateral vestibular hypofunction may need once a week sessions for 4 to 6 weeks; and persons with bilateral vestibular hypofunction may need once a week sessions for 8 to 12 weeks. In addition to supervised sessions, patients are provided a daily home exercise program. DISCLAIMER: These recommendations are intended as a guide for physical therapists and clinicians to optimize rehabilitation outcomes for persons with peripheral vestibular hypofunction undergoing vestibular rehabilitation.Video Abstract available for more insights from the author (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A124).

Variables associated with outcome in patients with bilateral vestibular hypofunction: Preliminary study.

BACKGROUND: Vestibular rehabilitation (VR) improves symptoms and function in some but not all patients with bilateral vestibular hypofunction (BVH). OBJECTIVE: The purpose of this retrospective study was to examine change following vestibular rehabilitation and to identify factors associated with rehabilitation outcome in patients with BVH. METHODS: Data from 69 patients with BVH were analyzed. Factors studied included patient characteristics, subjective complaints and physical function. Outcome measures included symptom intensity, balance confidence, quality of life, gait speed, fall risk, and dynamic visual acuity. Bivariate correlations were used to examine relationships of patient characteristics and baseline measures with outcome measures. One-way ANOVAs were used to compare outcomes in patients with BVH versus unilateral vestibular hypofunction (UVH). RESULTS: As a group, patients with BVH improved in all outcome measures except disability following a course of vestibular rehabilitation (VR); however, only 38-86% demonstrated a meaningful improvement, depending on the specific outcome measure examined. Several factors measured at baseline - age, DGI score, gait speed and perceived dysequilibrium - were associated with outcomes. For example, greater age was related to higher DVA scores at discharge; lower initial DGI scores were related to higher Disability scores at discharge. Compared to patients with UVH, reported previously [9], a smaller percentage of patients with BVH improve and to a lesser extent. CONCLUSION: Consideration of baseline factors may provide guidance for setting patient goals. Further research is needed determine what factors predict outcome and to develop more effective treatment strategies for those patients who do not improve.

Vestibular rehabilitation.

PURPOSE OF REVIEW: This review examines the research from 2011 through 2012 on treatment efficacy in two common vestibular disorders - vestibular hypofunction and benign paroxysmal positional vertigo (BPPV). RECENT FINDINGS: Significant numbers of randomized controlled trials now support the use of specific exercises for the treatment of patients with unilateral peripheral vestibular hypofunction. We do not know if some treatment approaches are more effective than others. There is preliminary evidence that head movement may be the component critical to recovered function and decreased symptoms. Some patient characteristics and initial assessment results appear to predict treatment outcome but the evidence is incomplete. Treatment of posterior canal BPPV canalithiasis is well established. New evidence supports certain treatments for horizontal canal BPPV. SUMMARY: Treatments for unilateral vestibular hypofunction and for posterior canal BPPV are effective; however, there are many as yet unanswered questions such as why some patients with vestibular hypofunction do not improve with a course of vestibular exercises. We also do not know what would be the best treatment for anterior canal BPPV or for multiple-canal involvement BPPV.

Variables associated with outcome in patients with unilateral vestibular hypofunction.

BACKGROUND: Not all individuals with unilateral vestibular hypofunction (UVH) have fewer subjective complaints and improved function after vestibular rehabilitation. OBJECTIVE: To identify factors and/or combinations of factors that are strongly associated with rehabilitation outcome in patients with UVH and that ultimately can be used to develop models to predict outcome. METHODS: Data from 209 patients with UVH were analyzed. All patients participated in similar vestibular rehabilitation (5 weeks of home exercises and once-weekly clinic visits). Outcome measures included intensity of oscillopsia and dysequilibrium, balance confidence, perceived disability, percentage of time symptoms interfered with activities, gait speed, fall risk, and dynamic visual acuity (DVA). Bivariate correlation and regression analysis were used to determine relationships between baseline (pretherapy) measures and outcome at discharge. RESULTS: No baseline measure of subjective complaints (eg, symptom intensity) predicted improvement of physical function (eg, gait speed). Similarly, no baseline measure of physical function predicted improvement of subjective complaints. Certain patient characteristics, such as gender and time from onset, were not related to any outcomes. Most comorbidities did not affect outcome; however, anxiety and/or depression were associated with lower balance confidence and higher percentage of time for which symptoms interfered with activities at discharge. Baseline DVA and gait speed were associated with DVA and gait speed at discharge, respectively. Dynamic gait index (DGI) at discharge was affected by age, baseline DGI, and history of falls. CONCLUSION: These results provide insight into recovery of patients with UVH. Therapists can use this information in the development of expectations for patient outcome and treatment priorities.

Misclassification of patients with spinocerebellar ataxia as having psychogenic postural instability based on computerized dynamic posturography.

Specific criteria have been developed based on computerized dynamic posturography (CDP) to assist clinicians in identifying patients with psychogenic balance problems (Cyr and Cevette, 1993; Cevette et al., 1995; Goebel et al., 1997; Gianoli et al., 2000). Patients with known spinocerebellar ataxia (SCA) meet several of the criteria for psychogenic balance problem and risk being misclassified as having imbalance of psychogenic origin. However, our research shows that patients with SCA may be distinguished from patients with psychogenic balance problems in several ways. We compared test performance on CDP and the observation of specific behaviors that are associated with psychogenic balance problems in patients with SCA (n = 43) and patients with known psychogenic balance problems (n = 40). Chi-square analysis was used to determine if there were significant differences between the groups for the frequency of each criterion for psychogenic CDP and Observed Behaviors. Level of significance was Bonferroni corrected for multiple comparisons. Sensitivity, specificity, and positive likelihood ratios were calculated for each criterion. Hierarchical cluster analysis was used to examine whether the two patient groups demonstrated similar groupings of criteria. Comparison of the results of these analyses identified two criteria that were significantly more frequent in the psychogenic group than in the SCA group: regular periodicity of sway and circular sway. Sensitivity, specificity, and positive likelihood ratios identified two additional criteria, inconsistent motor responses and large lateral sway that also seem to suggest a psychogenic component to a person's imbalance. Prospective studies are needed to validate the usefulness of these findings.

A Prototype Head-Motion Monitoring System for In-Home Vestibular Rehabilitation Therapy.

This work reports the use of a head-motion monitoring system to record patient head movements while completing in-home exercises for vestibular rehabilitation therapy. Based upon a dual-axis gyroscope (yaw and pitch, ± 500-degrees/sec maximum), angular head rotations were measured and stored via an on-board memory card. The system enabled the clinician to document exercises at home. Several measurements were recorded in one patient with unilateral vestibular hypofunction: The total time of exercise for the week (118 minutes) was documented and compared with expected weekly exercise time (140 minutes). For gaze stabilization exercises, execution time of 60 sec was expected, and observed times ranged from 75-100 sec. An absence of rest periods between each exercise instead of the recommended one minute rest period was observed. Maximum yaw head velocities from approximately 100-350 degrees/sec were detected. A second subject provided feedback concerning the ease of use of the HAMMS device. This pilot study demonstrates, for the first time, the capability to capture the head-motion "signature" of a patient while completing vestibular rehabilitation exercises in the home and to extract exercise regime parameters and monitor patient adherence. This emerging technology has the potential to greatly improve rehabilitation outcomes for individuals completing in-home gaze stabilization exercises.

Efficacy of gaze stability exercises in older adults with dizziness.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether the addition of gaze stability exercises to balance rehabilitation would lead to greater improvements of symptoms and postural stability in older adults with normal vestibular function who reported dizziness. METHODS: Participants who were referred to outpatient physical therapy for dizziness were randomly assigned to the gaze stabilization (GS) group (n = 20) or control (CON) group (n = 19). Dizziness was defined as symptoms of unsteadiness, spinning, a sense of movement, or lightheadedness. Participants were evaluated at baseline and discharge on symptoms, balance confidence, visual acuity during head movement, balance, and gait measures. The GS group performed vestibular adaptation and substitution exercises designed to improve gaze stability, and the CON group performed placebo eye exercises designed to be vestibular neutral. In addition, both groups performed balance and gait exercises. RESULTS: There were no baseline differences (P > .05) between the GS and CON groups in age, sex, affect, physical activity level, or any outcome measures. Both groups improved significantly in all outcome measures with the exception of perceived disequilibrium. However, there was a significant interaction for fall risk as measured by Dynamic Gait Index (P = .026) such that the GS group demonstrated a significantly greater reduction in fall risk compared with the CON group (90% of the GS group demonstrated a clinically significant improvement in fall risk versus 50% of the CON group). DISCUSSION AND CONCLUSIONS: This study provides evidence that in older adults with symptoms of dizziness and no documented vestibular deficits, the addition of vestibular-specific gaze stability exercises to standard balance rehabilitation results in greater reduction in fall risk.

Oculomotor strategies and their effect on reducing gaze position error.

OBJECTIVE: Vestibular adaptation exercises have been shown to improve gaze stability during active head rotation in individuals with vestibular hypofunction. Little is known, however, of the types of eye movements used during passive head rotation and their effect on gaze stability in individuals with vestibular hypofunction. The primary purpose of this study was to determine differences in oculomotor strategies and their effect on stabilizing gaze during ipsilesional passive and active head rotations in vestibular hypofunction. PATIENTS: Subjects with unilateral (n = 4) and bilateral (n = 3) vestibular hypofunction and healthy subjects (n = 4) based on bithermal caloric and rotational chair testing. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: Head and eye velocity and position data measured with scleral search coil. RESULTS: Subjects with unilateral and bilateral vestibular hypofunction generated 3 types of gaze-stabilizing eye movements with ipsilesional head impulses: slow vestibular ocular reflex, compensatory, and corrective saccades. The types of eye movements generated during active and passive head impulses were highly individualized. Gaze position error was reduced when compensatory saccades were recruited as part of the gaze-stabilizing strategy. CONCLUSION: Rehabilitation for individuals with vestibular hypofunction should identify individuals' unique gaze stability preferences and attempt to facilitate compensatory saccades.

Recovery of dynamic visual acuity in bilateral vestibular hypofunction.

OBJECTIVE: To determine the effect of vestibular exercises on the recovery of visual acuity during head movement in patients with bilateral vestibular hypofunction (BVH). DESIGN: Prospective, randomized, double-blinded study. SETTING: Outpatient clinic, academic setting. PATIENTS: Thirteen patients with BVH, aged 47 to 73 years. INTERVENTION: One group (8 patients) performed vestibular exercises designed to enhance remaining vestibular function, and the other (5 patients) performed placebo exercises. MAIN OUTCOME MEASURES: Measurements of dynamic visual acuity (DVA) during predictable head movements using a computerized test; measurement of intensity of oscillopsia using a visual analog scale. RESULTS: As a group, patients who performed vestibular exercises showed a significant improvement in DVA (P = .001), whereas those performing placebo exercises did not (P = .07). Only type of exercise (ie, vestibular vs placebo) was significantly correlated with change in DVA. Other factors examined, including age, time from onset, initial DVA, and complaints of oscillopsia and disequilibrium, were not significantly correlated with change in DVA. Change in oscillopsia did not correlate with change in DVA. CONCLUSIONS: Use of vestibular exercises is the main factor involved in recovery of DVA in patients with BVH. We theorize that exercises may foster the use of centrally programmed eye movements that could substitute for the vestibulo-ocular reflex. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00411216.

Reliability of clinical measures used to assess patients with peripheral vestibular disorders.

PURPOSE: The purposes of this research were to (1) determine test-retest reliability of clinical measures of self reported disability and subjective complaints, gait, and fall risk; and (2) establish normal variability for each of these measures based on test-retest variability in people with peripheral vestibular disorders. METHODS: Sixteen patients with confirmed peripheral vestibular disorders performed 2 trials of each of the measures within a single physical therapy session. The measures included rating of disability, percent of day affected by dizziness, head movement induced dizziness, preferred gait speed, gait deviations, and Dynamic Gait Index. In order to assess test-retest reliability of the measures intraclass correlation coefficients (ICC) were calculated. RESULTS: All measurement tools demonstrated excellent reliability (ICC 3,1 = 0.86 - 1.00) except for head movement induced dizziness (ICC 3,1 = 0.48). For each measure we report normal variability as tested within a single session. DISCUSSION: Clinical measures commonly used in the assessment of vestibular patients were found to have excellent test-retest reliability, except for the subjective measure of head movement-induced dizziness. CONCLUSION: Incorporation of valid and reliable assessments in clinical practice is critical in order to demonstrate the effectiveness of therapeutic intervention.

Prediction of fall risk reduction as measured by dynamic gait index in individuals with unilateral vestibular hypofunction.

OBJECTIVE: To determine the effect of vestibular rehabilitation on reduction of fall risk in individuals with unilateral vestibular hypofunction and to identify those factors that predict fall risk reduction. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Forty-seven patients with unilateral vestibular hypofunction, aged 28 to 86 years, who were at risk for falls on initial assessment. INTERVENTION: All patients underwent vestibular rehabilitation including adaptation exercises, designed to improve gaze stability, and gait and balance exercises. MAIN OUTCOME MEASURES: Fall risk (Dynamic Gait Index), visual acuity during head movements (Dynamic Visual Acuity), and subjective complaints were measured initially, at 2-week intervals, and at completion of physical therapy. RESULTS: As a group, the patients had significantly reduced risk for falls (p <0.001) after rehabilitation. Time from onset of symptoms did not affect the efficacy of vestibular rehabilitation. Both older (> or = 65 yr) and younger (< 65 yr) adults showed significant reductions in fall risk with vestibular rehabilitation (p <0.001). However, a significantly greater proportion (Chi2= 0.016) of older adults remained at risk for falls at discharge compared with young adults (45% versus 11%). Initial Dynamic Gait Index and Dynamic Visual Acuity scores predicted fall risk reduction in patients with unilateral vestibular hypofunction. A model was developed using initial Dynamic Gait Index and Dynamic Visual Acuity scores to predict fall risk reduction. CONCLUSIONS: Vestibular rehabilitation is effective in significantly reducing fall risk in individuals with unilateral vestibular deficit. The model predicts fall risk reduction with good sensitivity (77%) and specificity (90%).

Cervico-ocular reflex in normal subjects and patients with unilateral vestibular hypofunction.

OBJECTIVE: To determine whether the cervico-ocular reflex contributes to gaze stability in patients with unilateral vestibular hypofunction. STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Patients with unilateral vestibular hypofunction (n = 3) before and after vestibular rehabilitation and healthy subjects (n = 7). INTERVENTIONS: Vestibular rehabilitation. MAIN OUTCOME MEASURES: We measured the cervico-ocular reflex in patients with unilateral vestibular hypofunction before and after vestibular rehabilitation and in healthy subjects. To measure the cervico-ocular reflex, we recorded eye movements with a scleral search coil while the trunk moved at 0.3, 1.0, and 1.5 Hz beneath a stabilized head. To determine whether the head was truly stabilized, we measured head movement using a search coil. RESULTS: We found no evidence of cervico-ocular reflex in any of the seven healthy subjects or in two of the patients with unilateral vestibular hypofunction. In one patient with chronic unilateral vestibular hypofunction, the cervico-ocular reflex was present before vestibular rehabilitation only for leftward trunk rotation (relative head rotation toward the intact side). After 5 weeks of placebo exercises, there was no change in the cervico-ocular reflex. After an additional 5 weeks that included vestibular exercises, cervico-ocular reflex gain for leftward trunk rotation had increased threefold. In addition, there was now evidence of a cervico-ocular reflex for rightward trunk rotation, potentially compensating for the vestibular deficit. CONCLUSION: The cervico-ocular reflex appears to be a highly inconsistent mechanism. The change of the cervico-ocular reflex in one patient after vestibular exercises suggests that the cervico-ocular reflex may be adaptable in some patients.

Optimizing the sensitivity of the head thrust test for identifying vestibular hypofunction.

BACKGROUND AND PURPOSE: The head thrust test (HTT) is used to assess the vestibulo-ocular reflex. Sensitivity and specificity for diagnosing unilateral vestibular hypofunction (UVH) in patients following vestibular ablation is excellent (100%), although sensitivity is lower (35%-39%) for patients with nonsurgically induced UVH. The variability of the test results may be from moving the subject's head outside the plane of the lateral semicircular canals as well as using a head thrust of predictable timing and direction. The purpose of this study was to examine sensitivity and specificity of the horizontal HTT in identifying patients with UVH and bilateral vestibular hypofunction (BVH) when the head was flexed 30 degrees in attempt to induce acceleration primarily in the lateral semicircular canal and the head was moved unpredictably. SUBJECTS: The medical records of 176 people with and without vestibular dysfunction (n=79 with UVH, n=32 with BVH, and n=65 with nonvestibular dizziness) were studied. METHODS: Data were retrospectively tabulated from a de-identified database (ie, with health information stripped of all identifiers). RESULTS: Sensitivity of the HTT for identifying vestibular hypofunction was 71% for UVH and 84% for BVH. Specificity was 82%. DISCUSSION AND CONCLUSION: Ensuring the head is pitched 30 degrees down and thrust with an unpredictable timing and direction appears to improve sensitivity of the HTT.

Recovery of dynamic visual acuity in unilateral vestibular hypofunction.

OBJECTIVE: To determine the effect of vestibular exercises on the recovery of visual acuity during head movement in patients with unilateral vestibular hypofunction. STUDY DESIGN: Prospective, randomized, double-blind study. SETTING: Ambulatory referral center. PATIENTS: Twenty-one patients with unilateral vestibular hypofunction, aged 20 to 86 years. INTERVENTION: One group (13 patients) performed vestibular exercises designed to enhance the vestibulo-ocular reflex, and the other group (8 patients) performed placebo exercises. The placebo group was switched to vestibular exercises after 4 weeks. OUTCOME MEASURES: Measurements of dynamic visual acuity (DVA) during predictable (DVA-predictable) and unpredictable (DVA-unpredictable) head movements by means of a computerized test and measurement of intensity of oscillopsia by means of a visual analog scale. RESULTS: As a group, patients who performed vestibular exercises showed a significant improvement in DVA-predictable (P<.001) and DVA-unpredictable (P<.001), while those performing placebo exercises did not (P =.07). On the basis of stepwise regression analysis, the leading factor contributing to improvement was vestibular exercises. This reached significance for DVA-predictable (P =.009) but not DVA-unpredictable (P =.11). Other factors examined included age, time from onset, initial DVA, oscillopsia, and duration of treatment. Changes in oscillopsia did not correlate with DVA-predictable or DVA-unpredictable. CONCLUSIONS: Use of vestibular exercises is the main factor involved in recovery of DVA-predictable and DVA-unpredictable in patients with unilateral vestibular hypofunction. Exercises may foster the use of centrally programmed eye movements that could substitute for the vestibulo-ocular reflex. The DVA-predictable would benefit more from this than would DVA-unpredictable.