Physical and Vestibular Physical Therapy Referrals in People With Alzheimer Disease.

People with Alzheimer disease (AD) are at increased risk of falls and disproportionately burdened with vestibular impairment compared with healthy older adults. Although physical therapy (PT) and vestibular physical therapy (VPT) are effective rehabilitation interventions in improving balance and fall risk, referral patterns for these services in the AD population are understudied. A retrospective chart review was conducted of patients seen for primary AD care at a tertiary AD referral center to investigate the frequency of rehabilitation referrals. Of the 801 people with AD seen for AD care in 1 year, 48 individuals (6.0%) were referred to PT and 5 individuals (0.6%) to VPT. People with AD appear to receive very infrequent PT and VPT referrals, despite the potentially large number of people with AD who could benefit from PT and VPT services to improve their balance and vestibular function.

Navigating Through a COVID-19 World: Avoiding Obstacles.

Individuals with balance and gait problems encounter additional challenges navigating this post-coronavirus disease-2019 (COVID-19) world. All but the best fitting facemasks partially obscure the lower visual field. Facemask use by individuals with balance and gait problems has the potential to further compromise walking safety. More broadly, as the world reopens for business, balance and gait testing in clinics and research laboratories will also be impacted by facemask use. Here, we highlight some of the challenges faced by patients, clinicians, and researchers as they return to "normal" after COVID-19.Video Abstract is available for insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A328).

VestAid: A Tablet-Based Technology for Objective Exercise Monitoring in Vestibular Rehabilitation.

(1) Background: Current vestibular rehabilitation therapy is an exercise-based approach aimed at promoting gaze stability, habituating symptoms, and improving balance and walking in patients with mild traumatic brain injury (mTBI). A major component of these exercises is the adaptation of the vestibulo-ocular reflex (VOR) and habituation training. Due to acute injury, the gain of the VOR is usually reduced, resulting in eye movement velocity that is less than head movement velocity. There is a higher chance for the success of the therapy program if the patient (a) understands the exercise procedure, (b) performs the exercises according to the prescribed regimen, (c) reports pre- and post-exercise symptoms and perceived difficulty, and (d) gets feedback on performance. (2) Methods: The development and laboratory evaluation of VestAid, an innovative, low-cost, tablet-based system that helps patients perform vestibulo-ocular reflex (VORx1) exercises correctly at home without therapist guidance, is presented. VestAid uses the tablet camera to automatically assess patient performance and compliance with exercise parameters. The system provides physical therapists (PTs) with near real-time, objective (head speed and gaze fixation compliance), and subjective (perceived difficulty and pre- and post- exercise symptoms) metrics through a web-based provider portal. The accuracy of the head-angle and eye-gaze compliance metrics was evaluated. The accuracy of estimated head angles calculated via VestAid's low-complexity algorithms was compared to the state-of-the-art deep-learning method on a public dataset. The accuracy of VestAid's metric evaluation during the VORx1 exercises was assessed in comparison to the output of an inertial measurement unit (IMU)-based system. (3) Results: There are low mean interpeak time errors (consistently below 0.1 s) across all speeds of the VORx1 exercise, as well as consistently matching numbers of identified peaks. The spatial comparison (after adjusting for the lag measured with the cross-correlation) between the VestAid and IMU-based systems also shows good matching, as shown by the low mean absolute head angle error, in which for all speeds, the mean is less than 10 degrees. (4) Conclusions: The accuracy of the system is sufficient to provide therapists with a good assessment of patient performance. While the VestAid system's head pose evaluation model may not be perfectly accurate as a result of the occluded facial features when the head moves further towards an extreme in pitch and yaw, the head speed measurements and associated compliance measures are sufficiently accurate for monitoring patients' VORx1 exercise compliance and general performance.

Vestibular Physical Therapy in Individuals With Cognitive Impairment: A Theoretical Framework.

Falls are a major health care concern in individuals with Alzheimer disease (AD) and their caregivers. Vestibular impairment is a known risk factor for falls, and individuals with AD have been shown to have an increased prevalence of vestibular loss compared with age-matched controls. Vestibular physical therapy (VPT) is effective in improving balance and reducing fall risk in cognitively-intact persons with vestibular impairment. However, the effectiveness of VPT in improving balance and reducing falls in individuals with AD who have vestibular loss has never been explored. SUMMARY OF KEY POINTS:: In this article, we apply prevailing ideas about rehabilitation and motor learning in individuals with cognitive impairment (IwCI) to VPT. RECOMMENDATIONS FOR CLINICAL PRACTICE:: We propose a modification of current evidence-based VPT protocols for IwCI using the strength-based theoretical framework that emphasizes the motor learning abilities of IwCI. In addition, we highlight the importance of establishing an excellent rapport with IwCI, and present key strategies for optimizing the therapeutic relationship. In ongoing work, we are assessing the efficacy of this modified VPT protocol in IwCI to improve balance and reduce falls.

Global Positioning System Indicators of Community Mobility and Future Health Outcomes Among Older Adults.

BACKGROUND: We examined the relationship between global positioning system (GPS) indicators of community mobility and incident hospitalizations, emergency department (ED) visits, and falls over 1-year in community-dwelling older adults. METHODS: We performed a secondary analysis of a randomized trial investigating a physical therapy intervention to improve mobility in older adults. One hundred and forty-eight participants (mean age: 76.9 ±â€…6.2 years; 65% female) carried a GPS device following the postintervention visit. Over 1-year, new hospitalizations, falls, and ED visits were reported. GPS indicators of community mobility included the median area and compactness of the standard deviation ellipse (SDE), the median percentage of time spent outside of home (TOH), and median maximum distance from home. Generalized linear models assessed the association between 1-year risk of outcomes and GPS measures adjusted for age, race, gender, body mass index, comorbidity burden, and fall history. RESULTS: The mean ±â€…standard deviation of the median SDE area was 4.4 ±â€…8.5 km2, median SDE compactness 0.7 ±â€…0.2, median percentage TOH 14.4 ±â€…12.0%, and median maximum distance from home was 38 ±â€…253 km. Each 5% increase in median percentage TOH was associated with a 24% lower risk of hospitalization (incident rate ratio = IRR = 0.76, 95%CI: 0.61-0.95; p = .01). The association persisted after covariate adjustment (IRR = 0.78, 95%CI: 0.63-0.98; p = .03). No significant associations appeared for any GPS indicators with incident falls or ED visits. CONCLUSIONS: Increased TOH was associated with a lower risk of incident hospitalization over 1 year among community-dwelling older adults. Restricted community mobility may be an indicator of activity limitations related to future health outcomes, but further study is warranted.

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.

Vestibular Physical Therapy Treatment of Individuals Exposed to Directed Energy.

INTRODUCTION: Following suspected sonic attacks on U.S. Embassies, a subset of individuals presented with a unique cluster of symptoms believed to have resulted from exposure to directed energy. Directed energy has been described as exposure to a unique sound/pressure phenomenon such as infrasonic or ultrasonic acoustic or electromagnetic energy. The Joint Force does not have an established protocol to guide vestibular physical therapy for individuals exposed to directed energy. Therefore, we have provided evidence-based guidance for the treatment of oculomotor- and vestibular-related impairments from similar populations. MATERIALS AND METHODS: Published evidence was used to inform suggestions for clinical best practice. We offer resources for the management of non-oculomotor- and non-vestibular-related impairments, before discussing physical therapy interventions for dizziness and imbalance. RESULTS: The physical therapist should design a treatment program that addresses the individual's health condition(s), body structure and function impairments, activity limitations, and participation restrictions after suspected directed energy exposure. This treatment program may include static standing, compliant surface standing, weight shifting, modified center of gravity, gait, and gaze stabilization or vestibular-ocular reflex training. Habituation may also be prescribed. Interventions were selected that require little to no specialized equipment, as such equipment may not be available in all settings (i.e., operational environments). CONCLUSIONS: Evidence-based guidance for prescribing a comprehensive vestibular physical therapy regimen for individuals exposed to directed energy may aid in their rehabilitation and return to duty. This standardized approach can help physical therapists to treat complaints that do not match any previously known medical conditions but resemble brain injury or vestibular pathology.

Effects of a Physical Therapist Intervention on GPS Indicators of Community Mobility in Older Adults: A Secondary Analysis of a Randomized Controlled Trial.

OBJECTIVE: The authors compared the effects of a standard strength and endurance intervention with a standard plus timing and coordination training intervention on community mobility measured using global positioning systems (GPS) among community-dwelling older adults in this secondary analysis of a randomized controlled trial. METHODS: Participants were randomized to a standard or a standard plus timing and coordination training program. Community mobility was measured using the Life Space Assessment (LSA) and GPS indicators of community mobility at baseline, as well as at 12 (immediately after the intervention), 24, and 36 weeks. Linear mixed models were used for analysis. RESULTS: There were 166 participants with GPS data at baseline, including 81 in the standard plus group and 85 in the standard group. The groups did not differ in participant characteristics or GPS measures at baseline. There were no significant within-group changes in GPS indicators of community mobility or LSA score over time, nor between-group differences of the same. CONCLUSION: There were no significant changes in community mobility with either intervention or between-intervention differences. These findings suggest that interventions targeting physical function alone may not be sufficient to improve community mobility or participation in older adults. Future research should focus on the development of multifaceted interventions targeted to improve real-world participation. IMPACT: The studied interventions did not significantly change community mobility measured using GPS-derived community mobility measures or self-report measures in older adults, suggesting that more comprehensive interventions may be needed to target improvements in community mobility.

The Association of Mobility Determinants and Life Space Among Older Adults.

BACKGROUND: It is important to understand the factors associated with life-space mobility so that mobility disability can be prevented/treated. The purpose of this study was to identify the association between mobility determinants and life space among older adults. METHODS: This study was a cross-sectional analysis of 249 community-dwelling older adults (mean age = 77.4 years, 65.5% female, 88% White), who were recruited for a randomized, controlled, clinical intervention trial. Associations between cognitive, physical, psychosocial, financial, and environmental mobility determinants and the life-space assessment (LSA) at baseline were determined using Spearman's correlation coefficients and one-way analysis of variance. Multivariate analysis was performed using multivariable linear regression models. RESULTS: The mean LSA score for the sample was 75.3 (SD = 17.8). Personal factors (age, gender, education, comorbidities), cognitive (Trail Making Test A and B), physical (gait speed, lower extremity power, 6-Minute Walk Test, Figure of 8 Walk Test, tandem stance, energy cost of walking, and Late-Life Function and Disability Function Scale), psychosocial (Modified Gait Efficacy Scale), and financial (neighborhood socioeconomic status) domains of mobility were significantly associated with LSA score. In the final regression model, age (ß = -0.43), lower extremity power (ß = 0.03), gait efficacy (ß = 0.19), and energy cost of walking (ß = -57.41) were associated with life space (R2 = 0.238). CONCLUSIONS: Younger age, greater lower extremity power, more confidence in walking, and lower energy cost of walking were associated with greater life space. Clinicians treating individuals with mobility disability should consider personal, physical, and psychosocial factors when assessing barriers to life-space mobility.

Physical Therapy Treatment of a Person Exposed to Directed Energy: A Case Report.

Directed energy exposure is a phenomenon that has been reported in Cuba and China by both U.S. and Canadian government employees. Persons exposed to directed energy report symptoms that resemble mild traumatic brain injury (concussion). No single case has been reported in the literature. A 43-year-old male with suspected directed energy exposure developed progressively worsening headaches, dizziness, auditory/vestibular symptoms, balance problems, difficulty sleeping, and cognitive/emotional complaints while assigned by the Department of State to Guangzhou, China. His physical therapy care is outlined and discussed to provide an in-depth understanding of his care and additional ideas that might benefit future diplomats and government employees who experience dizziness, visual complaints, and balance problems after suspected directed energy exposure. Coordinated multidisciplinary care with benchmarks of function before deployment is advised by the National Academies of Sciences.

Brain health correlates of mobility-related confidence.

BACKGROUND: Mobility is important for independence in older age. While brain health correlates of objectively measured mobility-related features like gait and balance have been reported, we aimed to test neuroimaging and cognitive correlates of subjective measures of mobility-related confidence. METHODS: We carried out a cross-sectional observational study comprised of N = 29 cognitively unimpaired older adult participants, mean age 75.8 ± 5.8, 52% female, 24% non-white. We measured cognition, hippocampal volume, white matter hyperintensities, cerebral amyloid-ß (Aß), and gait and balance confidence. We tested associations using unadjusted Spearman correlations and correlations partialling out covariates of interest one at a time. RESULTS: Greater gait confidence was associated with better attention (unadjusted ρ = 0.37, p = 0.05; partially attenuated by adjustment for age, APOE4, anxiety, motivation, gait speed, or Aß); executive performance (unadjusted ρ = 0.35, p = 0.06; partially attenuated by adjustment for age, APOE4, gait speed, or Aß); and lower Aß levels (unadjusted ρ = -0.40, p = 0.04; partially attenuated by adjustment for age, depressive symptoms, motivation, or gait speed). Greater balance confidence was associated with better global cognition (unadjusted ρ = 0.41, p = 0.03; partially attenuated by adjustment for APOE4, gait speed, or Aß); attention (unadjusted ρ = 0.46, p = 0.01; robust to adjustment); and lower Aß levels (unadjusted ρ = -0.35, p = 0.07; partially attenuated by adjustment for age, education, APOE4, depressive symptoms, anxiety, motivation, or gait speed). CONCLUSIONS: Self-reported mobility-related confidence is associated with neuroimaging and cognitive measures and would be easy for providers to use in clinical evaluations. These associations should be further evaluated in larger samples, and longitudinal studies can help determine temporality of declines.

Utility of VestAid to Detect Eye-Gaze Accuracy in a Participant Exposed to Directed Energy.

INTRODUCTION: The VestAid is a tablet-based application that provides feedback about a patient's eye/head movements during exercise after concussion. The goal of this case series was to determine if VestAid could be used to detect eye-gaze accuracy in a participant exposed to directed energy (DE). MATERIALS AND METHODS: The VestAid results of a participant with DE were compared to an age- and gender-matched healthy control, a participant post-concussion, and a participant with vestibular neuritis. A tablet with VestAid software was utilized to record eye-gaze accuracy and head speed during VORx1 exercises using eye and facial recognition as participants were exposed to 12 visual scenes. RESULTS: The participant with DE consistently had difficulty with eye-gaze accuracy when the head was rotated towards the right for all trials. The participant with DE had poor eye-gaze accuracy during all phases of the head turn cycle compared to the control participant (mean 47.91%, [SD = 7.32%] for the DE participant versus mean 94.28%, [SD = 5.87%] for the control participant). Post-exercise dizziness and perceived difficulty in the 12 exercises completed by the participant with DE were strongly related (Spearman's rho = 0.7372, P = .0062). The participant with DE had the lowest scores on 10 of the 12 head movement trials. CONCLUSIONS: VestAid provided unique information about eye-gaze accuracy that detected eye movement abnormalities in the participants with DE exposure, concussion, and vestibular neuritis. The objective metrics of eye-gaze stability correlate with participants' symptoms and perceived difficulty of the eye/head movements.

Self-Reported Sense of Direction and Vestibular Function in the Baltimore Longitudinal Study of Aging (BLSA).

Sense of direction is an individual's ability to navigate within an environment and generate a mental map of novel environments. Although sense of direction is correlated with psychometric tests of spatial ability, it also reflects an individual's real-world spatial ability that is not fully captured by laboratory-based assessments. Sense of direction is known to vary widely in the population and has been shown to decline with age. However, other factors that contribute to an individual's sense of direction have not been well-characterized. Vestibular impairment has been linked to reduced spatial cognitive ability, which encompasses spatial memory and navigation skills. Several studies have shown that vestibular input is necessary for effective spatial cognition, notably accurate spatial navigation ability. These studies have typically considered laboratory-based spatial navigation assessments; however, the influence of vestibular function on variation in real-world sense of direction is unknown. In this study, we evaluated whether vestibular function is associated with self-reported sense of direction. Participants for this cross-sectional study were recruited from the Baltimore Longitudinal Study of Aging, a longstanding cohort study of healthy aging. In a modified version of the Santa Barbara Sense-of-Direction (SBSOD) Scale, participants rated statements about spatial and navigational abilities. A lower average score indicates poorer self-reported sense of direction. Vestibular function testing included cervical vestibular-evoked myogenic potential (VEMP) to assess saccular function, ocular VEMP to assess utricular function, and the video head-impulse test to assess semicircular canal function based on vestibular ocular reflex. The study sample included 82 participants with mean age of 71.0 (± 16.9) years and mean SBSOD score of 4.95(± 1.07). In a multivariate linear regression model, female sex and bilateral saccular loss were associated with a lower average SBSOD score. These data suggest that vestibular impairment contributes to the known variation in spatial navigation ability.

Facemasks Block Lower Visual Field in Youth Ice Hockey.

Wearing a facemask (FM) reduces the spread of COVID-19, but it also blocks a person's lower visual field. Many new public safety rules were created in response to COVID-19, including mandated FM wearing in some youth sports like youth ice hockey. We hypothesized that FM wearing in youth hockey players obstructs the lower field of view and may impact safety. Youth hockey players (n = 33) aged 12.03 (1.6) years button press when they saw an LED on the floor turn on in two conditions (wearing FM or no FM) in random order. An interleaved one-up/one-down two-alternative-forced-choice adaptive staircase design was used. Visual thresholds were calculated for each condition and participant. The visual angle threshold (VAT) was determined using standing eye height and the linear distance from the tip of the skates to the visual threshold. Paired t-tests determined whether mask wearing changed the VAT. We modeled the probability a player could see the puck on their stick in four distinct scenarios to estimate the potential impact of FM wearing during hockey play. The average unmasked VAT (11.4 degrees) was significantly closer to the skates than the masked VAT (20.3 degrees) (p < 0.001). Our model indicated a significant reduction in ability to visualize the puck using peripheral vision when more upright while wearing a FM. FM wearing compromised their lower visual field, suggesting a downward head tilt may be necessary to see the puck. Playing ice hockey while wearing a FM may lead to unsafe on-ice playing conditions due to downward head tilt to see the puck.

Fear Avoidance Beliefs Are Associated With Perceived Disability in Persons With Vestibular Disorders.

OBJECTIVE: The purpose of this study was to determine the association between fear-avoidance beliefs and disability in 3 months in people with vestibular disorders while accounting for demographic and clinical characteristics. METHODS: This prospective cohort study included people aged 18 to 100 years who reported dizziness. Participants were recruited from a balance disorders clinic and outpatient physical therapy clinics. All participants completed the Vestibular Activities Avoidance Instrument (VAAI) and the Hospital Anxiety and Depression Scale at baseline and the Vestibular Activities and Participation measure (VAP), dizziness Visual Analogue Scale (VAS), and 12-item Short Form Health Questionnaire at baseline and 3-month follow-up. A modified version of the VAAI included 9 items abstracted from the 81-item VAAI. The relationships between 9-item VAAI scores and follow-up measures of disability were assessed using Spearman correlation coefficients. Linear regression models were analyzed to determine the effect of fear-avoidance beliefs on follow-up VAP score while accounting for baseline outcome measures. RESULTS: All participants (n = 404) completed the baseline assessment (mean age = 54 years), and 286 (71%) completed the 3-month assessment. The mean 9-item VAAI score was 25 (SD = 14) at baseline and was significantly associated with VAP (ρ = 0.54), 12-item Short Form Health Questionnaire component scores (ρ = -0.53; -0.44), and dizziness VAS at follow-up (ρ = 0.37). Approximately 38% of the variation in VAP score at follow-up was predicted by age, number of medications, 9-item VAAI score, dizziness VAS, and Hospital Anxiety and Depression Scale-depression score when considered together (R2 = 0.38). CONCLUSION: Fear-avoidance beliefs are associated with measures of disability at 3 months and are predictive of activity limitations and participation restrictions at 3 months when controlling for age, medications, baseline dizziness, and depression symptom severity in people with vestibular disorders. IMPACT: Measurement of fear-avoidance beliefs may provide important prognostic information, suggesting that an assessment of fear-avoidance beliefs could be used by clinicians to identify individuals at greater risk of disability after a vestibular disorder. LAY SUMMARY: Fear-avoidance beliefs in people who have vestibular disorders are associated with disability at 3 months and predict limitations in daily activities at 3 months.

Management of Benign Paroxysmal Positional Vertigo in an Adult With Severe Osteogenesis Imperfecta.

The purpose of this case report was to describe the evaluation and management of atypical benign paroxysmal positional vertigo (BPPV) in an adult with severe osteogenesis imperfecta. A 29-year-old male was referred to a physical therapist with extensive experience in vestibular rehabilitation who provided horizontal canal BPPV treatment with a canalith repositioning maneuver over two treatment sessions. The individual's symptoms had reduced by 65% and his nystagmus during the roll test was reduced. Extreme care is needed to safely reposition individuals living with severe osteogenesis imperfecta, but the repositioning can reduce symptoms and improve quality of life. Laryngoscope, 130:2241-2244, 2020.

Automatically Evaluating Balance: A Machine Learning Approach.

Compared to in-clinic balance training, in-home training is not as effective. This is, in part, due to the lack of feedback from physical therapists (PTs). In this paper, we analyze the feasibility of using trunk sway data and machine learning (ML) techniques to automatically evaluate balance, providing accurate assessments outside of the clinic. We recruited sixteen participants to perform standing balance exercises. For each exercise, we recorded trunk sway data and had a PT rate balance performance on a scale of 1-5. The rating scale was adapted from the Functional Independence Measure. From the trunk sway data, we extracted a 61-dimensional feature vector representing the performance of each exercise. Given these labeled data, we trained a multi-class support vector machine (SVM) to map trunk sway features to PT ratings. Evaluated in a leave-one-participant-out scheme, the model achieved a classification accuracy of 82%. Compared to participant self-assessment ratings, the SVM outputs were significantly closer to PT ratings. The results of this pilot study suggest that in the absence of PTs, ML techniques can provide accurate assessments during standing balance exercises. Such automated assessments could reduce PT consultation time and increase user compliance outside of the clinic.

Effects of long-term vestibular rehabilitation therapy with vibrotactile sensory augmentation for people with unilateral vestibular disorders - A randomized preliminary study.

BACKGROUND AND OBJECTIVE: This pilot study aimed to investigate the effects of incorporating vibrotactile sensory augmentation (SA) on balance performance among people with unilateral vestibular disorders (UVD). METHODS: Eight participants with UVD were recruited. Participants completed 18 balance training sessions across six weeks in a clinical setting. Four participants (68.1±7.5 yrs) were randomized to the experimental group (EG) and received trunk-based vibrotactile SA while performing the balance exercises, and four participants (63.1±11.3 yrs) were assigned to the control group (CG); CG participants completed the balance training without SA. Clinical and kinematic balance performance measures were collected before training; midway through training; and one week, one month, and six months after training. RESULTS: All participants, regardless of group, demonstrated improvements in a subset of the clinical or balance metrics immediately following completion of the balance training protocol. The EG showed significantly greater improvements than the CG for the Activities-specific Balance Confidence Scale and postural stability during the two standing balance exercises with head movements. The EG also had larger improvements than the CG for the Sensory Organization Test (SOT), Mini Balance Evaluations Systems Test, Gait Speed Test, Dynamic Gait Index, Functional Gait Assessment, and vestibular reliance metric calculated based on the SOT. CONCLUSIONS: Incorporating vibrotactile SA into vestibular rehabilitation programs may lead to additional benefits that may be retained up to six months after training compared to training without vibrotactile SA. A larger study is warranted to demonstrate statistical significance between the groups.

Relationship between subjective visual vertical and balance in individuals with multiple sclerosis.

BACKGROUND: Subjective visual vertical (SVV) deviations have been correlated to abnormal cerebellar function in individuals diagnosed with multiple sclerosis (MS). It has been shown that individuals with MS have increased incidence of SVV abnormalities, yet this is not routinely tested in this population during physical therapy evaluation. OBJECTIVE: This study aims to determine if there is a relationship between SVV and balance performance in people with MS who have cerebellar involvement. We hypothesize that individuals with greater SVV deviations will have worse balance performance. METHODS: Fifteen females and five males (mean age 54.5 years [±7.03 SD]) with the diagnosis of MS and cerebellar involvement participated. Computerized SVV testing included rod and rod-and-frame conditions. None of the balance outcomes were correlated with the rod-only condition. Because there was a difference in magnitude of results within the rod-and-frame condition, based on whether the frame was rotated clockwise (CW) or counterclockwise (CCW), they were analysed independently. RESULTS: For all six of the balance outcomes, there was a statistically significant moderate correlation with SVV deviations when the frame was tilted CCW: Barthel Index (r = -0.47, p = 0.018), Berg Balance Score (r = -0.59, p = 0.003), gait velocity (r = -0.52, p = 0.010), International Cooperative Ataxia Rating Scale (r = 0.56, p = 0.006), Scale for the Assessment and Rating of Ataxia (r = 0.62, p = 0.002), and Timed Up and Go (r = 0.58, p = 0.003). Interestingly, the Barthel Index was the only outcome that had statistical significance with a moderate correlation (r = -0.66, p = 0.001) when the frame was rotated CW. In this cohort, greater deviations during the rod-and-frame condition of SVV testing correlated with worse functional outcomes, especially when the frame was tilted CCW. CONCLUSION: Individuals with MS who demonstrate decreased balance performance may rely more heavily on visual backgrounds. Implementation of SVV assessment for individuals with MS may provide clinicians with valuable information to identify clinical interventions.

Reliability and Validity of Ratings of Perceived Difficulty During Performance of Static Standing Balance Exercises.

BACKGROUND: Standardized instruments for measuring the intensity of balance exercises in clinical environments are lacking. OBJECTIVE: The objective of this study was to develop a method for quantifying the perceived intensity of standing balance exercises. DESIGN: A test-retest study design was used, with repeated evaluations within the same visit and between visits 1 week later. METHODS: Sixty-two participants who were healthy and 18 to 85 years old (with a mean age of 55 years [SD = 20 years]; 50% women) were enrolled. On each of 2 visits, they performed 2 sets of 24 randomized static standing exercises consisting of combinations of the following factors: surface, vision, stance, and head movement. Postural sway was measured with an inertial measurement unit, and ratings of perceived difficulty (RPD) were recorded using numerical and qualitative scales. The RPD scales were validated against the quantitative sway measures using a general linear model approach. The test-retest reliability of the RPD scales was examined using a weighted kappa coefficient. RESULTS: Both RPD scales were associated with postural sway measures with correlation coefficients > 0.6 for the whole sample. The test-retest reliability of the ratings varied considerably across the different balance exercises, and the highest weighted kappa values occurred for RPD scores on the numerical scale within the second visit, as moderate agreement was achieved in 18 of the 24 exercises. LIMITATIONS: The limitations are that the RPD scales need to be validated for other types of balance exercises and in individuals with balance disorders. CONCLUSIONS: The RPD scores correlated with the magnitude of postural sway, suggesting that they can be used as a proxy measure of perceived intensity of balance exercises.