Evidence for the differential efficacy of yaw and pitch gaze stabilization mechanisms in people with multiple sclerosis.

People with multiple sclerosis (PwMS) who report dizziness often have gaze instability due to vestibulo-ocular reflex (VOR) deficiencies and compensatory saccade (CS) abnormalities. Herein, we aimed to describe and compare the gaze stabilization mechanisms for yaw and pitch head movements in PwMS. Thirty-seven PwMS (27 female, mean ± SD age = 53.4 ± 12.4 years old, median [IQR] Expanded Disability Status Scale Score = 3.5, [1.0]. We analyzed video head impulse test results for VOR gain, CS frequency, CS latency, gaze position error (GPE) at impulse end, and GPE at 400 ms after impulse start. Discrepancies were found for median [IQR] VOR gain in yaw (0.92 [0.14]) versus pitch-up (0.71 [0.44], p < 0.001) and pitch-down (0.81 [0.44], p = 0.014]), CS latency in yaw (258.13 [76.8]) ms versus pitch-up (208.78 [65.97]) ms, p = 0.001] and pitch-down (132.17 [97.56] ms, p = 0.006), GPE at impulse end in yaw (1.15 [1.85] degs versus pitch-up (2.71 [3.9] degs, p < 0.001), and GPE at 400 ms in yaw (-0.25 [0.98] degs) versus pitch-up (1.53 [1.07] degs, p < 0.001) and pitch-down (1.12 [1.82] degs, p = 0.001). Compared with yaw (0.91 [0.75]), CS frequency was similar for pitch-up (1.03 [0.93], p = 0.999) but lower for pitch-down (0.65 [0.64], p = 0.023). GPE at 400 ms was similar for yaw and pitch-down (1.88 [2.76] degs, p = 0.400). We postulate that MS may have preferentially damaged the vertical VOR and saccade pathways in this cohort.

Utricular Dysfunction and Hearing Impairment Affect Spatial Navigation in Community-dwelling Healthy Adults: Analysis from the Baltimore Longitudinal Study of Aging.

INTRODUCTION: Spatial navigation, the ability to move through one's environment, is a complex skill utilized in everyday life. The effects of specific vestibular end-organ deficits and hearing impairments on spatial navigation have received little to no attention. We hypothesized that hearing impairment adversely affects spatial navigation and that bi-modal impairments (vestibular and hearing) further impair navigation ability. METHODS: Data from 182 participants in the Baltimore Longitudinal Study of Aging who had interpretable results for the video head impulse test (vHIT), cervical (cVEMP) and ocular (oVEMP) vestibular evoked myogenic potentials, audiometric testing, and the triangle completion test (TCT) were retrospectively analyzed. Multiple linear regression, controlling for age, sex, and cognition, was employed to identify predictors of TCT performance in terms of end-point error, angle deviation, and distance walked. RESULTS: oVEMP abnormalities were associated with larger end-point error (p=0.008) and larger angle deviation (p=0.002) but were not associated with distance walked (p=0.392). Abnormalities on cVEMP and vHIT were not associated with distance walked (p=0.835, p=0.300), end-point error (p=0.256, p=0.808), or angle deviation (p=0.192, p=0.966). Compared with normal hearing adults, hearing impaired adults walked a shorter distance during the TCT (p=0.049) but had similar end-point error (p=0.302) and angle deviation (p=0.466). There was no interaction between vestibular and hearing function for predicting spatial navigation ability. CONCLUSION: In this cohort analysis, utricular dysfunction and hearing impairment were associated with poorer spatial navigation performance. We postulate that hearing impairment negatively affects one's ability to use real-time, intrinsic auditory cues and/or prior experience to guide navigation.

Compensatory saccades differ between those with vestibular hypofunction and multiple sclerosis pointing to unique roles for peripheral and central vestibular inputs.

Individuals with peripheral or central vestibular dysfunction recruit compensatory saccades (CSs) in response to high acceleration, yaw head impulses. Although CSs have been shown to be an effective strategy for reducing gaze position error (GPE) in individuals with peripheral hypofunction, for individuals with central vestibular dysfunction, the effectiveness of CS is unknown. The purpose of our study was to compare the effectiveness of CS, defined as the ability to compensate for head velocity and eye position errors, between persons with central and peripheral vestibular dysfunction. We compared oculomotor responses during video head impulse testing between individuals with unilateral peripheral vestibular deafferentation, a disorder of the peripheral vestibular afferents, and individuals with multiple sclerosis, a condition affecting the central vestibular pathways. We hypothesized that relative to individuals with peripheral lesions, individuals with central dysfunction would recruit CSs that were delayed and inappropriately scaled to head velocity and GPE. We show that CSs recruited by persons with central vestibular pathology were not uniformly deficient but instead were of a sufficient velocity to compensate for reductions in VOR gain. Compared to those with peripheral vestibular lesions, individuals with central pathology also recruited earlier covert CS with amplitudes that were better corrected for GPE. Conversely, those with central lesions showed greater variability in the amplitude of overt CS relative to GPE. These data point to a unique role for peripheral and central vestibular inputs in the recruitment of CS and suggest that covert CSs are an effective oculomotor strategy for individuals with multiple sclerosis.NEW & NOTEWORTHY Compensatory saccades (CSs) are recruited by individuals with unilateral vestibular deafferentation (UVD) to compensate for an impaired vestibulo-ocular reflex (VOR). The effectiveness of CS in multiple sclerosis (MS), a central vestibular impairment, is unknown. We show that in UVD and in MS, covert CSs compensate for reduced VOR gain and minimize gaze position error (GPE), yet in >50% of individuals with MS, overt CS worsened GPE, suggesting unique roles for peripheral and central vestibular inputs.

The Gait Disorientation Test: A New Method for Screening Adults With Dizziness and Imbalance.

OBJECTIVE: To develop and evaluate a new method for identifying gait disorientation due to vestibular dysfunction. DESIGN: The gait disorientation test (GDT) involves a timed comparison of the ability to walk 6.096 m with eyes open versus eyes closed. In this prospective study, participants were grouped based on vestibular function. All participants completed a clinical examination, self-report- and performance-based measures relevant to vestibular rehabilitation, and the tasks for the GDT. Vestibular-impaired participants underwent the criterion standard, videonystagmography and/or rotational chair testing. SETTING: Ambulatory clinic, tertiary referral center. PARTICIPANTS: Participants (N=40) (20 vestibular-impaired, 30 women, 49.9±16.1years old) were enrolled from a convenience/referral sample of 52 adults. MAIN OUTCOME AND MEASURE(S): We determined test-retest reliability using the intraclass correlation coefficient model 3,1; calculated the minimal detectable change (MDC); examined concurrent validity through Spearman correlation coefficients; assessed criterion validity with the area under the curve (AUC) from receiver operator characteristic analysis; and computed the sensitivity, specificity, diagnostic odds ratio (DOR), likelihood ratios for positive (LR+) and negative (LR-) tests, and posttest probabilities of a diagnosis of vestibulopathy. The 95% confidence interval demonstrates measurement uncertainty. RESULTS: Test-retest reliability was 0.887 (0.815, 0.932). The MDC was 3.7 seconds. Correlations with other measures ranged from 0.59 (0.34, 0.76) to -0.85 (-0.92, -0.74). The AUC was 0.910 (0.822, 0.998), using a threshold of 4.5 seconds. The sensitivity and specificity were 0.75 (0.51, 0.91) and 0.95 (0.75, 1), respectively. The DOR=57 (6, 541.47), LR+ =15 (2.18, 103.0), and LR- =0.26 (0.12, 0.9). Positive posttest probabilities were 89%-94%. CONCLUSIONS AND RELEVANCE: The GDT has good reliability, excellent discriminative ability, strong convergent validity, and promising clinical utility.

Reliability and validity of the force intersection point in the assessment of human quiet standing balance.

BACKGROUND: This study evaluated psychometric properties of the Intersection Point Height, derived from ground-on-feet force characteristics, as a tool for assessing balance control. We compare this metric with traditional center of pressure (CP) measurements. METHODS: Data from a public dataset of 146 participants, divided into younger (<60 years old) and older (≥60 years old) adults, were analyzed. Clinical tests included the Short Falls Efficacy Scale-International, International Physical Activity Questionnaire-Short Form, Trail Making Tests A and B, and the Mini-Balance Evaluation Systems Test. Reliability and validity were assessed through the intra-class correlation coefficient (ICC[3,1]) for mean Intersection Point Height in each test condition and Spearman's rho between summative Intersection Point Height (the sum of intra-condition mean values across all test conditions within one subject) and other variables of interest, respectively. FINDINGS: Mean Intersection Point Height showed good to excellent reliability (ICC = 0.712-0.901), similar to that of CP velocity (ICC = 0.733-0.922) and greater than that of variance CPx (0.475-0.768). Summative Intersection Point Height exhibited strong convergent validity with Trail Making Tests A and B (rho = 0.49, p < 0.001) and the Mini-Balance Evaluation Systems Test (rho = -0.47, p < 0.001). At most, a weak to moderate association (rho = 0.39-0.49, p < 0.001) was found between intra-condition mean Intersection Point Height with CP metrics. Intra-condition mean Intersection Point Height demonstrated weak to moderate convergent validity with several clinical measures (rho = 0.32-0.52, p < 0.001). In contrast, at most, a weak to moderate association (rho = 0.39-0.49, p < 0.001) was found between intra-condition mean Intersection Point Height with CP metrics. INTERPRETATION: The Intersection Point Height is a reliable and valid balance measure. Further, we believe that it is a more comprehensive evaluation than CP metrics.

Vestibular perceptual testing from lab to clinic: a review.

Not all dizziness presents as vertigo, suggesting other perceptual symptoms for individuals with vestibular disease. These non-specific perceptual complaints of dizziness have led to a recent resurgence in literature examining vestibular perceptual testing with the aim to enhance clinical diagnostics and therapeutics. Recent evidence supports incorporating rehabilitation methods to retrain vestibular perception. This review describes the current field of vestibular perceptual testing from scientific laboratory techniques that may not be clinic friendly to some low-tech options that may be more clinic friendly. Limitations are highlighted suggesting directions for additional research.

Regional differences in patient-reported outcomes as a proxy of healthcare practices for Americans living with vestibular symptoms.

BACKGROUND: Geographical location is known to affect health outcomes; however, evidence regarding whether location affects healthcare for persons suspected to have vestibular dysfunction is lacking. OBJECTIVE: To investigate whether location affects healthcare seeking and outcomes for adults with symptoms of vestibular pathology. METHODS: We assessed for regional disparities associated with demographics, diagnosis, chronological factors, and financial expenditures from Americans who participated in the Vestibular Disorders Association registry (N = 905, 57.4±12.5 years, 82.7% female, 94.8% White, and 8.1% Hispanic or Latino). Respondents were grouped per geographical regions defined by the United States Census Bureau. RESULTS: There were no significant between-region differences for age (p = 0.10), sex (p = 0.78), or ethnicity (p = 0.24). There were more Asian respondents in the West versus the Midwest (p = 0.05) and more Black respondents in the South versus the West (p = 0.05). The time to first seek care was shorter in the Northeast (17.3 [SD = 49.5] weeks) versus the South (42.4 [SD = 83.7] weeks), p = 0.015. The time from the first healthcare visit to receiving a final diagnosis was shorter in the Northeast (46.5 [SD = 75.4] weeks) versus the South (68.9 [SD = 89.7] weeks), p = 0.015. Compared to the Midwest, fewer respondents in the Northeast reported "no" out-of-pocket financial impact, p = 0.039. CONCLUSIONS: Geographical location affects healthcare seeking and outcomes for persons suspected to have vestibular dysfunction.

Patients' Experiences with Management of Benign Paroxysmal Positional Vertigo: Insights from the Vestibular Disorders Association Registry.

Introduction: Benign paroxysmal positional vertigo (BPPV) is the most frequently occurring peripheral vestibular disorder. Clinical practice guidelines (CPG) for BPPV exist; however, little is known about how affected patients perceive their condition is being managed. We aimed to leverage registry data to evaluate how adults who report BPPV are managed. Material and Methods: We retrospectively analyzed of data from 1,262 adults (58.4 ± 12.6 years old, 81.1% female, 91.1% White) who were enrolled in the Vestibular Disorders Association Registry from 2014 to 2020. The following patient-reported outcomes were analyzed by proportions for those who did and did not report BPPV: symptoms experienced, falls reported, diagnostics undertaken, interventions received (eg, canalith repositioning maneuvers [CRMs], medications), and responses to interventions. Results: Of the 1,262 adults included, 26% reported being diagnosed with BPPV. Many adults who reported BPPV (83%) also endorsed receiving additional vestibular diagnoses or may have had atypical BPPV. Those with BPPV underwent magnetic resonance imaging and were prescribed medications more frequently than those without BPPV (76% vs 57% [χ2=36.51, p<0.001] and 85% vs 78% [χ2=5.60, p=0.018], respectively). Falls were experienced by similar proportions of adults with and without BPPV (55% vs 56% [χ2==11.26, p=0.59]). Adults with BPPV received CRMs more often than those without BPPV (86% vs 48%, χ2=127.23, p<0.001). More registrants with BPPV also endorsed benefit from CRMs compared to those without BPPV (51% vs 12% [χ2=105.30, p<0.001]). Discussion: In this registry, BPPV was often reported with other vestibular disorders. Healthcare utilization was higher than would be expected with care based on the CPG. The rates of falls in those with and without BPPV are higher than previously reported. Adults with BPPV reported significant differences in how their care is managed and their overall outcomes compared to those without BPPV. Conclusion: Patient-reported outcomes provide useful information regarding the lived experience of adults with BPPV.

Unique compensatory oculomotor behavior in people living with multiple sclerosis.

INTRODUCTION: Globally, there are 3 million people living with multiple sclerosis (PLW-MS). A large proportion of PLW-MS have abnormal vestibular function tests that suggest central vestibular lesions. Yet, data regarding vestibular-ocular control in PLW-MS is limited. Thus, we aimed to further characterize compensatory saccade (CS) behavior in PLW-MS. METHODS: We analyzed video head impulse data from four groups of six age- and sex-matched adults: people living with mild MS (PLW-mild-MS, people living with moderate MS (PLW-moderate-MS), people living with unilateral vestibular deafferentation (PLW-UVD), and healthy controls (HC). RESULTS: PLW-moderate-MS had lower lateral canal vestibulo-ocular reflex (VOR) gain bilaterally compared to PLW-mild MS (p < 0.001), HC (p < 0.001), and PLW-UVD (p < 0.001). CS frequency was higher for impulses towards the less affected side in PLW-moderate-MS versus the more (p = 0.01) and less (p < 0.001) affected sides in PLW-mild-MS. CS latency was shorter (p < 0.001) and CS peak velocity was lower (p < 0.001) with impulses towards the more affected side versus the less affected side in PLW-moderate-MS. However, CS peak velocity with impulses towards each side was similar in PLW-mild-MS (p = 0.12). Gaze position error (GPE) was larger after impulses towards the more affected side versus the less affected side in PLW-moderate-MS (p < 0.001) and PLW-mild-MS (p < 0.001). MS-related disability was moderately associated with VOR gain (p < 0.001) and GPE (p < 0.001). Additionally, we identified micro-saccades and position correcting saccades that were uniquely employed by PLW-MS as compensatory gaze stabilizing strategies. CONCLUSIONS: In PLW-MS, the characteristics of compensatory oculomotor behavior depend on the extent of residual VOR gain.

Greater Disability Is Associated with Worse Vestibular and Compensatory Oculomotor Functions in People Living with Multiple Sclerosis.

Globally, there are nearly three million people living with multiple sclerosis (PLW-MS). Many PLW-MS experience vertigo and have signs of vestibular dysfunction, e.g., low vestibulo-ocular reflex (VOR) gains or the presence of compensatory saccades (CSs), on video head impulse testing (vHIT). We examined whether the vestibular function and compensatory oculomotor behaviors in PLW-MS differed based on the level of MS-related disability. The VOR gain, CS frequency and latency, and gaze position error (GPE) were calculated from the individual traces obtained during six-canal vHIT for 37 PLW-MS (mean age 53.4 ± 12.4 years-old, 28 females) with vertigo and/or an imbalance. The subjects were grouped by their Expanded Disability Status Scale (EDSS) scores: PLW-min-MS (EDSS = 1.0-2.5, n = 8), PLW-mild-MS (EDSS = 3.0-4.5, n = 23), and PLW-moderate-MS (EDSS = 5.0-6.0, n = 6). The between-group differences were assessed with Kruskal-Wallis tests. The VOR gains for most of the canals were higher for PLW-min-MS compared to PLW-mild- and mod-MS, respectively. CS occurred less often in PLW-min-MS versus PLW-mild- and mod-MS, respectively. No clear trend in CS latency was found. The GPE was often lower for PLW-min-MS compared to PLW-mild- and mod-MS, respectively. Thus, our data demonstrate that worse VOR and compensatory oculomotor functions are associated with a greater MS-related disability. PLW-MS may benefit from personalized vestibular physical therapy.

Validation of a next-generation sensory organization test in adults with and without vestibular dysfunction.

BACKGROUND: The traditional Sensory Organization Test (T-SOT) is a gold standard balance test; however, the psychometric properties of assessing sensory organization with a virtual-reality-based posturography device have not been established. OBJECTIVE: Our overall aims were to assess the criterion, concurrent, and convergent validity of a next-generation Sensory Organization Test (NG-SOT). METHODS: Thirty-four adults (17 vestibular-impaired) participated. We compared the area under the curve (AUC) for receiver operator characteristic (ROC) analysis for the T-SOT and NG-SOT composite scores. Between-group and between-test differences for the composite and sensory analysis scores from each SOT were assessed using Wilcoxon Rank Sum tests. Additionally, we ran Spearman correlations between the NG-SOT composite score and outcomes of interest. RESULTS: The AUCs for the NG-SOT and T-SOT were 0.950 (0.883, 1) and 0.990 (0.969, 1) respectively (p = 0.168). The median composite, vision, and visual preference scores were lower on the NG-SOT compared to the T-SOT; whereas, the median somatosensory score was higher on the NG-SOT compared to the T-SOT. Associations between the composite score and patient-reported or performance-based outcomes ranged from poor to strong. CONCLUSIONS: The NG-SOT is a valid measure of balance in adults. However, the results of the NG-SOT and T-SOT should not be used interchangeably.

Instrumented Gait Analysis to Identify Persistent Deficits in Gait Stability in Adults With Chronic Vestibular Loss.

Importance: Regaining the ability to walk safely is a high priority for adults with vestibular loss. Thus, practitioners need comprehensive knowledge of vestibulopathic gait to design, provide, and/or interpret outcomes of interventions. To date, few studies have characterized the effects of vestibular loss on gait. Objectives: To investigate the use of an instrumented 2-minute walk test in adults with vestibular loss, to further characterize vestibulopathic gait, and to assess whether those with chronic vestibular loss have enduring gait deficits. Design, Setting, and Participants: This cross-sectional study, conducted between April 3, 2018, and June 27, 2019, recruited adults 20 to 79 years of age from an academic, tertiary, hospital-based, ambulatory care setting who were healthy or had confirmed unilateral or bilateral vestibular hypofunction. Of the 43 adults who were screened from convenience and referred samples, 2 declined, and 7 were excluded because of health conditions. Exposures: The main exposure was the instrumented 2-minute walk test, which was conducted with participants using wearable inertial measurement units while they walked a 10-m path at their self-selected speed and turned 180° in their self-selected direction at either end. Main Outcomes and Measures: The primary measures were spatiotemporal gait metrics (eg, stride length [SL] and peak whole-body turning velocity). Multivariate analysis of variance was used to assess between-group differences. Validity was assessed using the area under the curve from receiver operator characteristic analyses. Results: Data from 17 healthy adults (mean [SD] age, 39.27 [11.20] years; 13 [76%] female) and 13 adults with vestibular loss (mean [SD] age, 60.50 [10.81] years; 6 [46%] female) were analyzed. Very large between-group differences were found for SL (left) (estimated marginal mean [SE] for healthy vs vestibular groups, 1.47 [0.04] m vs 1.31 [0.04] m; Cohen d, 1.35; 95% CI, 0.18-2.52), SL (right) (estimated marginal mean [SE] for healthy vs vestibular groups, 1.46 [0.04] m vs 1.29 [0.04] m; Cohen d, 1.44; 95% CI, 0.25-2.62), and peak turn velocity (estimated marginal mean [SE] for healthy vs vestibular groups, 240.17 [12.78]°/s vs 189.74 [14.70]°/s; Cohen d, 1.23; 95% CI, 0.07-2.40). The area under the curve was 0.79 (95% CI, 0.62-0.95) for SL (left), 0.81 (95% CI, 0.64-0.97) for SL (right), and 0.86 (95% CI, 0.72-0.99) for peak turn velocity. Conclusions and Relevance: In this cross-sectional study, instrumented gait analysis had good discriminative validity and revealed persistent deficits in gait stability in those with chronic vestibular loss. The findings of this study suggest that these clinically and functionally meaningful deficits could be targets for vestibular rehabilitation.

Effect of Repetitive Administration of a Next-generation Sensory Organization Test in Adults With and Without Vestibular Dysfunction.

HYPOTHESIS: The overall aim was to assess the effects of repetitive testing on performance on a next-generation Sensory Organization Test (NG-SOT). BACKGROUND: The psychometric properties of sensory organization assessment with a next-generation posturography device are not fully characterized. Thus, a better understanding of the reliability of the NG-SOT is required to support its use as an outcome measure. METHODS: Forty adults (20 vestibular-impaired) participated. Test-retest reliability was determined using the interclass correlation coefficient [ICC (3,1)] for the composite, somatosensory, vision, vestibular, and visual preference scores. Learning effects were assessed by analyzing the change in the composite score over time. RESULTS: Analyzing the NG-SOT scores across all participants produced the following interclass correlation coefficients [95% confidence interval (CI)]: composite = 0.95 (0.92, 0.97), somatosensory = 0.20 (-0.06, 0.44), vision = 0.93 (0.88, 0.96), vestibular = 0.91 (0.85, 0.94), and visual preference = 0.19 (-0.07, 0.43). The mean differences (95% CI; p value) for the composite score between administrations were: 2.7 (1.0, 4.4; 0.002) for visits 1 and 2; 1.4 (-0.3, 3.1; 0.099) for visits 2 and 3; 0.7 (-1.0, 2.4; 0.403) for visits 3 and 4; and 0.4 (-1.3, 2.1; 0.653) for visits 4 and 5. CONCLUSIONS: Test-retest reliability was excellent for the composite, vision, and vestibular scores, but it was poor for the somatosensory and visual preference scores. A learning effect for the composite score was identified, but performance was stable after two administrations. Changes in the composite score that are greater than 6.5 points exceed the measurement error for the test.

Impaired re-weighting of sensory feedback for maintenance of postural control in children with developmental coordination disorder.

To further the understanding of postural control impairments seen in children with developmental coordination disorder (DCD) and the effect of these impairments on motor performance in these children, 30 children with and without DCD (mean age=9 years, 7 months +/- 1 year, 10 months) were administered the Movement Assessment Battery for Children (M-ABC), Wechsler Abbreviated Scale of Intelligence and the Sensory Organization Test. Analyses of covariance revealed that children with DCD had greater difficulty maintaining postural control when visual and somatosensory feedback were compromised in sensory conflict environments (p=.031). Group differences in postural control were independent of age. Additionally, no correlation was seen between motor performance on the M-ABC and postural control measures for the Sensory Organization Test. Our results demonstrate that impaired ability to utilize vestibular feedback while re-weighting somatosensory and visual feedback for orientation may be responsible, in part, for the postural control impairments observed in some children with DCD.

Effects of vestibular and balance rehabilitation on sensory organization and dizziness handicap.

This retrospective study was undertaken to assess balance recovery and dizziness handicap in 32 patients after a vestibular and balance rehabilitation program. Outcomes were compared between 12 patients with peripheral vestibular disorders and 20 patients with central or mixed balance disorders. The patients were tested with posturography (sensory organization test [SOT]) and the Dizziness Handicap Inventory (DHI) before and after their therapy program. The vestibular SOT, composite SOT, and functional DHI scores obtained before and after exercise were significantly improved in both the peripheral and central groups. The visual SOT mean scores obtained before and after therapy were significantly different only for the group with central or mixed vestibular disorders. Changes in SOT scores were not directly correlated with changes in DHI scores. Outcome measures of vestibular rehabilitation protocols confirmed objective and subjective improvement of balance and dizziness handicap in patients with peripheral and central vestibular disorders.

Outcomes after rehabilitation for adults with balance dysfunction.

OBJECTIVES: To assess balance, dynamic gait, and dynamic visual acuity outcomes after a vestibular and balance rehabilitation program and to determine which variables were significantly associated with improved balance and ambulation. DESIGN: Retrospective case series. SETTING: Outpatient setting at a tertiary care facility. PARTICIPANTS: Twenty patients who were seen for vestibular and balance therapy between July 1999 and June 2000. INTERVENTIONS: A customized exercise program was developed for each patient according to the results of the assessment and included the following interventions, as indicated: gaze stabilization, balance and gait training, and habituation exercises. MAIN OUTCOME MEASURES: The Dynamic Gait Index (DGI), Berg Balance Scale (BBS), Dynamic Visual Acuity Test (DVAT), and computerized post urography (Sensory Organization Test [SOT]). RESULTS: The mean change scores for the DGI showed significant improvement for both patients with peripheral vestibular dysfunction and patients with central balance disorders. For the central balance disorders group, the BBS score also showed significant improvement. No difference was noted for pretherapy and posttherapy SOT scores between groups. The total group appeared to show an average improvement of more than 2 lines on the visual acuity chart on the clinical DVAT. Patients who were 66 years or older were 1.5 times more likely to score less than 20 on the DGI, and those whose pretherapy vertical dynamic visual acuity was 20/80 or worse were 1.3 times more likely to score less than 20 on the DGI. CONCLUSIONS: Patients showed functional improvements in balance, visual acuity, and gait stability after balance and vestibular physical therapy. Age and pretherapy vertical dynamic visual acuity score influenced dynamic gait outcome after a balance rehabilitation program.