THE PERCENTAGE OF PEOPLE reported to have central

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1 76 ORIGINAL ARTICLE Physical Therapy for Vestibular Kathryn E. Brown, MS, PT, NCS, Susan L. Whitney, PhD, PT, NCS, ATC, Gregory F. Marchetti, PhD, PT, Diane M. Wrisley, PhD, PT, NCS, Joseph M. Furman, MD, PhD ABSTRACT. Brown KE, Whitney SL, Marchetti GF, Wrisley DM, Furman JM. Physical therapy for central vestibular dysfunction. Arch Phys Med Rehabil 26;87: Objective: To determine if vestibular physical therapy (PT) leads to improved functional outcomes in people with central vestibular dysfunction. Design: Retrospective case series. Setting: Outpatient PT clinic. Participants: Forty-eight patients with central vestibular dysfunction met the criteria for inclusion in this retrospective chart review. The 48 patients were divided into various subgroups including central vestibulopathy, cerebellar dysfunction, stroke, mixed central and peripheral vestibulopathy, and posttraumatic central disorders. Intervention: Patients were treated with a custom-designed PT program for a mean of 5 visits over an average of 5 months. Main Outcome Measures: Patients completed the Activities-Specific Balance Confidence Scale, the Dizziness Handicap Inventory (DHI), the Dynamic Gait Index, the Timed Up & Go test, and the Five Times Sit-to-Stand (FTSTS) Test. Results: Significant differences were demonstrated between initial evaluation and discharge in each of the assessment measures for the entire group. Post hoc tests were performed to determine if there was a significant difference in any of the assessment measures by diagnosis. vestibular diagnostic subgroup was shown to affect pre- to postintervention differences in the functional and disability measures (P.5). With the exception of the FTSTS, effect sizes of change due to PT intervention were greater in those persons with severe disability at baseline as determined by a DHI score of more than 6. Conclusions: Patients with central vestibular dysfunctions improved in both subjective and objective measures of balance after PT intervention. Persons with cerebellar dysfunction improved the least. Key Words: Balance; Rehabilitation; Treatment outcome; Vestibular function tests. 26 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation From the Department of Physical Therapy, School of Health and Rehabilitation Science, University of Pittsburgh, Pittsburgh, PA (Brown, Whitney); Centers for Rehab Services Balance and Vestibular Clinic (Brown, Whitney, Wrisley) and Department of Otolaryngology (Whitney, Furman), University of Pittsburgh Medical Center, Pittsburgh, PA; Department of Physical Therapy, Rangos School of Health Professions, Duquesne University, Pittsburgh, PA (Marchetti); Department of Rehabilitation Science, State University of New York, Buffalo, NY (Wrisley); and Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA (Furman). Presented in part to the Association for Research in Otolaryngology, February 25, 23, Daytona Beach, FL, and the American Physical Therapy Association Combined Sections, February 7, 24, Nashville, TN. Supported in part by the National Institutes of Health (grant no. DC5384). No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Reprint requests to Susan L. Whitney, PhD, PT, NCS, ATC, University of Pittsburgh, 635 Forbes Tower, Pittsburgh, PA 1526, whitney@pitt.edu /6/ $32./ doi:1.116/j.apmr THE PERCENTAGE OF PEOPLE reported to have central vestibular disorders by tertiary balance and vestibular clinics in various studies ranges between 7% and 45%, 1-5 yet little is known about the effect of physical rehabilitation on their outcomes. Many different diagnoses constitute the category central vestibular dysfunction, making it difficult to determine which subgroups of central vestibular disorders improve with vestibular rehabilitation. nervous system disorders can cause typical peripheral vestibular symptoms such as dizziness, nausea and vomiting, imbalance, and/or gait abnormalities. 6-8 Patients with central vestibular disorders also commonly exhibit neurologic symptoms such as: extremity and facial weakness, 9 confusion, 9 headache, extremity and/or facial numbness, 8,1 dysarthria, 8-1 incoordination, 9,1 and visual deficits. 8-1 People with peripheral and central vestibular dysfunction have been shown to improve with vestibular rehabilitation physical therapy (PT). 2,3,11-27 However, people diagnosed with central or mixed central and peripheral vestibular dysfunction do not exhibit the same amount of improvement in functional outcomes after vestibular PT as patients with peripheral dysfunction. 2,23,28 The evidence is sparse for improvement in subjects with central vestibular dysfunction following PT intervention, 3,18-2,26 and we have found no randomized controlled studies examining the efficacy of PT in subjects with central vestibular disorders. The purpose of this study was to describe functional improvement and reduction in disability for patients with central vestibular disorders who participated in PT intervention. Specifically, an attempt was made to determine if there were differences in measured functional and disability outcomes after PT intervention, based on the following diagnostic subgroup classifications: stroke, cerebellar dysfunction, posttrauma, mixed central plus peripheral vestibulopathy, and central vestibulopathy. METHODS Seventy-two patients with a diagnosis of central vestibular dysfunction were identified through a retrospective chart review of patients seen for vestibular PT from January 1997 through May 21 at the Center for Rehab Services within the Eye and Ear Institute at the University of Pittsburgh Medical Center (Pittsburgh, PA). The University of Pittsburgh Institutional Review Board approved this study and designated this study exempt from human subject review. Forty-eight patients met the inclusion criteria, which included completing a neurologic and/or otologic examination by a neuro-otologist or neurologist, being diagnosed as having a central vestibular or mixed peripheral and central disorder by the physician, and having completed 2 or more PT sessions. Patients were excluded if they were diagnosed with migraine-related vestibulopathy or if they had a history of migraine. A description of all patients by diagnostic category is included in table 1. The different diagnoses included in this study were stroke excluding cerebellar stroke, cerebellar dysfunction, which included cerebellar degeneration or cerebellar stroke, posttraumatic central disorders, mixed central and peripheral vestibulopathy or central vestibulopathy that was not specified.

2 OUTCOMES BY CENTRAL VESTIBULAR DIAGNOSIS, Brown 77 Table 1: The Age, Sex, Duration of Symptoms, Number of PT Visits, and Fall History for Persons With Vestibular Diagnoses for 5 Subgroups of Patients With Characteristic Patients (N 48) (n 13) Patient Diagnostic Group (n 11) (n 1) Mixed and (n 9) tic (n 5) Age (y) Female sex 31 (65) 9 (69) 8 (73) 7 (7) 5 (56) 2 (4) Duration of symptoms (mo) No. of treatments Fall history* 23 (48) 5 (39) 7 (64) 8 (8) 2 (22) 1 (2) NOTE. Values are mean standard deviation (SD) or n (%). *The number and percentage of patients who reported a fall in the 6 months prior to examination. The mean age of all patients was years (range, 17 9y). There were 31 women and 17 men treated for a mean of 5 months with an average duration of symptoms before intervention of 33.6 months. Twenty-two patients (46%) used an assistive device. The patients were referred primarily from 5 physicians (34/48 patients) within the University of Pittsburgh otolaryngology practice. Local otolaryngologists or neurologists referred the remaining patients from the Pittsburgh area. Vestibular PT was administered by 1 of 4 physical therapists skilled in the examination and treatment of patients with vestibular and neurologic disorders. patients were treated with a customized treatment program specifically designed based on the results of the PT examination. The treatment consisted of 1 or more of the following: balance and gait training, general strengthening and flexibility exercises, and utilization of varied senses, particularly somatosensation and vision, to aid in maintaining balance. Treatment also included vestibular adaptation exercises for those with mixed peripheral and central disorders, substitution exercises for lost vestibular function, and education in use of assistive devices and safety awareness techniques to avoid falls. Vestibular adaptation refers to the ability to readjust the gain of the vestibulo-ocular or the vestibulospinal reflexes, whereas substitution refers to using alternative strategies to replace lost vestibular function. 29 During each visit, we asked patients to complete 2 selfperception scales: the Dizziness Handicap Inventory (DHI) and the Activities-Specific Balance Confidence (ABC) Scale. The DHI is a 25-item scale that assesses perceived level of handicap from symptoms of dizziness. 3 Scores on the DHI range from to 1. Higher scores indicated a greater level of handicap. The DHI includes 3 subscales: physical, emotional, and functional. 3 Patients also rated their level of confidence in their ability to maintain balance while performing 16 activities using the ABC Scale. 31 A score of 1% denotes that a person is completely confident that he/she will not lose their balance or become unsteady while performing the listed activities of daily living. Scores of less than 5% indicate a low level of functioning 32 and often reveal that a person cannot leave home without assistance. Scores of 67% and lower have recently been related to falls in community-living older persons, with a sensitivity of 84% and a specificity rating of 87.5%. 33 Scores between 5% and 8% correlate to individuals living in retirement communities and/or manifesting 1 or more chronic health conditions. 32 Scores of 8% or higher are expected in community-living older adults. 32 The ABC has been shown to be valid and reliable in patients with vestibular dysfunction as well. 34 Patients were also asked to report the number of falls experienced 6 months prior to the initiation of PT. During the PT initial examination and subsequent visits, we asked the patients to perform 1 or more of the following tasks: the Dynamic Gait Index (DGI), 35 the Timed Up & Go (TUG) test, 36 and the Five Times Sit-to-Stand (FTSTS) test. 37 The DGI consists of 8 gait tasks that include walking, walking at different speeds, walking with head movements in the pitch and yaw planes, pivoting, walking over objects, walking around objects and going up and down stairs. 35,38 The maximum score on the DGI is 24; scores of 19 or less have been related to self-reported number of falls in persons with vestibular disorders, regardless of age. 39 At each visit, we asked the patient to complete the TUG test. 36,4 The therapist recorded the speed at which the patient could stand up, walk 3m, turn around, walk back, and sit down. 36 Times of 13.5 seconds or greater have been related to increased risk of falling in the older adult. 41 Patients were asked to perform the FTSTS. It consists of moving as quickly as possible from sit to stand 5 times from a 43-cm height chair (floor to seat) with their arms folded. The FTSTS is a valid measure of balance and lower-extremity strength in older persons. 37 The FTSTS has been used previously in persons with vestibular dysfunction. 4 Data Analysis Scores on the DHI, ABC, DGI, and the composite score were compared before and after therapy, using the Wilcoxon signed-rank test, to determine whether statistically significant differences were observed after PT for the total group of subjects as well as for various diagnostic subgroups. Scores before and after PT on the TUG and FTSTS were compared using paired t tests for the total group of subjects as well as for individual diagnostic groups. We attempted to determine if there were differences in baseline DHI scores (a disability measure) based on diagnostic category. If level of perceived disability as measured by the DHI proved independent of diagnostic category, pre- to posttherapy changes in the ABC, DGI, and the TUG were to be compared between DHI disability levels ( 6 [mild to moderate impairment] vs 61 1 [severe impairment]). Disability, as measured by the DHI, has been shown to be associated with reported falls and greater functional impairments. 4 A contingency table with chi-square analyses was used to examine independence of diagnostic group and level of disability. The significance of pre- to posttreatment changes within disability groups (mild/moderate DHI scores vs severe DHI scores) was determined using the dependent t test (TUG) and the Wilcoxon signed-rank test (ABC, DGI). The impact of disability severity on treatment outcome was described, as measured by the DHI. Intervention effect size for each outcome measure, as defined by mean change due to intervention divided by the standard

3 78 OUTCOMES BY CENTRAL VESTIBULAR DIAGNOSIS, Brown ABC (%) DGI Mixed & Fig 1. ABC Scale before and after vestibular rehabilitation for all subjects and for diagnostic subgroups. NOTE. Values are mean SD. 4 Mixed & Fig 3. DGI before and after vestibular rehabilitation for all subjects and for diagnostic subgroups. NOTE. Values are mean SD. deviation (SD) at baseline, was determined for the mild/moderate and severe disability groups. RESULTS Age, sex, duration of symptoms, number of treatment visits, and proportion of subjects with a reported history of falls is presented in table 1 for all subjects and for each diagnostic subgroup. The mean duration of symptoms for the group was 33.6 months, suggesting that these patients had chronic disorders. The prevalence of self-reported falls in the 6 months prior to examination for the entire patient groups was 48%. This prevalence was highest among patients with a stroke etiology (8%) followed by patients with a cerebellar diagnosis (64%). Figures 1 through 5 display pre- and postrehabilitation means and SDs for the ABC, DHI, DGI, TUG, and FTSTS for the entire patient group and each diagnostic subgroup. Improvements after rehabilitation in each measure were noted for all patients and across all diagnostic subgroups. Table 2 shows the mean improvements pre- to postrehabilitation in the ABC, DHI, DGI, TUG, and FTSTS for all patients and for each diagnostic subgroup. As noted in table 2, statistically significant improvements pre- to postrehabilitation were observed in each mean outcome for the DHI, ABC, DGI, TUG, and the FTSTS. Analysis of improvements in functional and disability measures by diagnostic subgroups showed significant changes in the DHI, DGI, and TUG for patients with central vestibulopathy. Patients with a stroke etiology showed significant improvements in the DGI and FTSTS. Significant improvements in DGI scores were demonstrated in patients with mixed central and peripheral disorders. A significant improvement in DHI was seen in patients with a posttraumatic etiology (see table 2). Significant improvements in the composite score were observed in patients with a stroke etiology (P.5), mixed central and peripheral vestibulopathy, and central vestibulopathy (P.2). The diagnostic subgroups displayed varying degrees of significant improvement in the functional and disability measures (see table 2). Analysis of pre- to postrehabilitation functional and disability measures by diagnostic subgroup revealed a significant improvement in at least 1 functional and disability measure for each group (except for patients with cerebellar disorders) despite small subgroup sample sizes. Power analysis at the observed effect size for each functional and disability DHI TUG (s) Mixed & Mixed & Fig 2. Total DHI before and after vestibular rehabilitation for all subjects and for diagnostic subgroups. NOTE. Values are mean SD. Fig 4. TUG test before and after vestibular rehabilitation for all subjects and for diagnostic subgroups. NOTE. Values are mean SD.

4 OUTCOMES BY CENTRAL VESTIBULAR DIAGNOSIS, Brown 79 FTSTS (s) Mixed & Fig 5. FTSTS before and after vestibular rehabilitation for all subjects and for diagnostic subgroups. NOTE. Values are mean SD. measure indicated that a minimum sample size of 33 to 46 patients would be required to demonstrate significant improvements (at power 8%) in most functional and disability measures for each diagnostic subgroup. Disability category as measured by the DHI (mild/moderate vs severe) was found to be independent of diagnostic group (P.77). The mild to moderate DHI disability group improved 1.9 seconds on the TUG (t 2.85, P.1) and the severe disability group improved 5.9 seconds (t 2.8, P.2). The mild/moderate DHI disability group improved a mean of 3. points on the DGI (z 3.29, P.1) and the severe DHI disability group improved a mean of 4.8 DGI points (z 2.49, P.2). On the ABC Scale, the mild/moderate DHI disability group improved 13.2-percentage points (z 2.65, P.2) and the severe DHI group improved 11.7-percentage points (z 1.65, P.1). Figure 6 illustrates the intervention effect sizes for the 5 outcome measures for mild/moderate and the severe DHI subgroups. The intervention effect sizes were larger for the severe DHI subgroup on all measures, except for the FTSTS. DISCUSSION Most patients in this case series demonstrated improvement following vestibular PT, yet as a subgroup those with cerebellar dysfunction improved the least on 4 of the 5 functional and disability measures (ABC, DHI, DGI, FTSTS). Overall, the results concur with other studies, which indicate that patients with central vestibular disorders demonstrate improvements in objective and subjective measures of balance and postural control following therapy, 2,3,5,15,18-2,42 although this study is the first to suggest that people with cerebellar dysfunction have the poorest outcomes following vestibular rehabilitation. Although many of our functional, and/or self-report disability measures demonstrated statistically significant improvements, the clinical implications were not as clear. In all subgroups, mean ABC scores improved after rehabilitation. The mean total group change in ABC score was 13.4-percentage points over the course of therapy, yet the mean score at discharge was only 55%. Scores of 5% to 8% indicate a moderate level of functioning. 32 Although demonstrating improved scores, our patients may have still been at risk for falling, as Lajoie and Gallagher 33 have reported that ABC scores of less than 67% were related to increased risk of falling in community-living older adults. The discharge ABC scores indicate improvement, although this sample of patients continued to be impaired, with decreased confidence in their balance abilities. As a group, all patient subgroups with central vestibular disorders demonstrated improvement in the total DHI score. A change score of 18 is considered to be clinically significant, 3 yet none of the central subgroup classifications had mean changes of 18 or more. The central vestibulopathy group, stroke group, and posttrauma group were approaching the mean score of 18 with average changes on the DHI of 17.3, 16.4, and 17.6 respectively. The DGI scores improved in our subjects by a mean change of 3.8 points. Over half of the patients improved 4 points or more, which indicates a clinically significant improvement in gait function. 27 However, their discharge scores averaged 17. Shumway-Cook et al 43 defined scores of 19 or less on the DGI as indicating an increased risk of falling in community-dwelling older adults. Whitney et al 39 recently compared the relation between gait instability and falls history in people with vestibular disorders, with scores of 19 or less relating to reported falls in people with vestibular disorders. Sixty-one percent of our patients exhibited scores of 19 or less on the DGI at discharge, which appears to suggest that these individuals continue to be at increased risks for falls and continue to exhibit gait dysfunction. Badke et al 5 recently reported a DGI change of 4 in a group that consisted of approximately 75% of their patients having either a central or a mixed central and peripheral vestibular disorder. An average DGI score of 18 at discharge for people with central vestibular dysfunction was reported, which is very similar to our data. The subgroups demonstrating the largest Table 2: Pre- to Postrehabilitation Improvements for Various Functional or Disability Measures and the Statistical Significance in Patients Plus for Diagnostic Subgroups Measure Patients Patient Diagnostic Group Mixed and ABC Scale* (45) (12) (1) (1) (8) (5) DHI* (44) (12) (1) (9) (8) (5) DGI* (38) (11) (8) (6) (8) (5) TUG test (34) (9) (6) (7) (8) (4) FTSTS (12) (2) (2) (3) (2) (3) NOTE. Values are mean SD and (n). *Wilcoxon signed-rank test. Paired t test. Significance at P.1. Significance at P.5.

5 8 OUTCOMES BY CENTRAL VESTIBULAR DIAGNOSIS, Brown Fig 6. Intervention outcome measure effect sizes for patients with central vestibular dysfunction stratified by disease severity into mild and moderate (DHI scores <6) and severe (DHI scores >6) subgroups. change on the DGI were the central vestibulopathy group and the mixed central and peripheral group (mean change, 5.3) plus the stroke group (mean change, 4.7). The posttrauma group had only slight improvement on the DGI, yet they also started with the best mean score, possibly suggesting a ceiling effect with this subgroup on the DGI. The cerebellar group started with a preintervention score of 12 (similar to the central vestibulopathy group and the mixed central and peripheral group), yet they changed little over the course of rehabilitation. Scores of 13.5 seconds or greater on the TUG have been used to indicate an increased risk for falls in communitydwelling older adults. 41 Thirty-three percent of our patients demonstrated scores of greater than 13.5 seconds on the TUG at discharge. The posttrauma group improved the least on the TUG, yet were closest at baseline to normal with a mean score of 1 seconds at the beginning of therapy. Steffen et al 44 and Podsiadlo and Richardson 36 have reported a mean TUG score of 8.5 to 9 seconds for healthy men and women in their seventies. The FTSTS has been used to determine lower-extremity strength and balance. 37 Because so few people completed the test, it is difficult to make conclusions, yet it is clear that all subgroup scores improved over the course of rehabilitation. The cerebellar dysfunction group improved the least overall. Gill-Body et al 18 reported that patients with cerebellar dysfunction improved either on clinical balance measures, gait parameters, or self-perceived balance and dizziness measures. One of the 2 cerebellar patients reported by Gill-Body exhibited a clinically significant improvement in the TUG and in our study 2 of 6 cerebellar patients demonstrated clinically significant improvements in the TUG, suggesting similar results. 18 Because cerebellar dysfunction can be a degenerative condition, little change after rehabilitation may be expected. As a group, the patients with cerebellar disorders did improve on all 5 measures (ABC, DHI, DGI, TUG, FTSTS), yet the changes in scores were much less than the other subgroups with central conditions. The progressive nature of their disease might have been a limiting factor. It is possible that without PT intervention, the cerebellar group s initial scores might have gotten worse rather than improved slightly. The patients in our study continued to demonstrate physical impairments, perceived handicap from their dizziness, and were at increased risk of falling. This finding agrees with previous studies that indicate that patients with central vestibular loss do improve, but to a lesser degree than individuals with peripheral vestibular dysfunction. 2,23,28 There is no way to ascertain that all of the improvements seen in this group of patients were due to the PT interventions. The lack of a control group reduces the level of evidence provided for the effectiveness of PT intervention to increase function and reduce disability in persons with central vestibular disorders. It is possible that spontaneous recovery or reduction in condition severity could have occurred during the time that they were undergoing PT, which might have influenced patient performance. However, the symptom duration of the total group and the diagnostic subgroup means ranged from 1 months to 52 months. The chronicity of symptoms would appear to reduce the likelihood that the changes observed were due to spontaneous condition improvement. These patients were seen in a tertiary care practice setting and had intractable functional limitations that had not improved with management at other levels of care. The fact that these patients were seen in a tertiary care center with chronic functional limitations may enhance the inference that PT intervention was effective in some of these patients. The results of grouping by diagnosis indicate that each diagnostic category, except the cerebellar dysfunction group, showed significant improvement in at least 1 of the functional or disability measures. It has been suggested that people with mixed central and peripheral vestibular disorders improve the least compared with peripheral or central groups. 1 What is interesting is that in 2 of the 5 functional or disability measures, persons with both peripheral and central vestibular dysfunction had greater improvement than those with central vestibular dysfunction. There may be less difference in functional recovery than had previously been suggested between persons with central and combined central and peripheral vestibular findings. When analyzed by perceived handicap using the DHI, it was interesting to note that persons in the severe DHI category made greater changes on the DGI and the TUG than those in the mild/moderate DHI category. These findings suggest that PT intervention may be helpful even for those with severe central vestibular dysfunction, which has not been previously reported. Both the mild and moderate and severely disabled DHI patient subgroups displayed improvement in functional skills and perceived quality of life due to PT intervention. The size of the intervention effect, as presented in figure 6, appeared greater in the severe subgroup in all outcome measures except for the FTSTS. From these data, it appears that even severely involved patients with central vestibular dysfunction may benefit from a vestibular rehabilitation program. CONCLUSIONS Overall, patients with central vestibular dysfunction improve in their functional limitations due to dizziness and imbalance following PT, although it appears that people with cerebellar disease improve the least. It is difficult to categorize all patients with central vestibular dysfunction as a single group. Individual central vestibular diagnostic groups and groupings based on perceived handicap might respond differently to PT intervention. When intervention effect sizes were compared via DHI severity score, it was observed that patients in the most severe disability group demonstrated a greater intervention effect on all outcomes except for the FTSTS. The effect of baseline severity on intervention outcomes in persons with central vestibular dysfunction should be addressed in a larger sample in order to determine if this trend is statistically and clinically significant.

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