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Usher syndrome is an autosomal recessive disorder characterised by retinitis pigmentosa and congenital sensorineural hearing loss. A gene for Usher syndrome type II (USH2) has been localised to chromosome 1q32-q41. DNA from a family with four of seven sibs affected with clinical characteristics of Usher syndrome type II was genotyped using markers spanning the 1q32-1q41 region. These included D1S70 and D1S81, which are believed to flank USH2. Genotypic results and subsequent linkage analysis indicated non-linkage of this family to these markers. The A test analysis for heterogeneity with this family and 32 other Usher type II families was statistically significant at p < 0.05. Further clinical evaluation of this family was done in light of the linkage results to determine if any phenotypic characteristics would allow for clinical identification of the unlinked type. No clear phenotypic differences were observed; however, this unlinked family may represent a previously unreported subtype of Usher type II characterised by a milder form of retinitis pigmentosa and mild vestibular abnormalities. Heterogeneity of Usher syndrome type II complicates efforts to isolate and clone Usher syndrome genes using linkage analysis and limits the use of DNA markers in early detection of Usher type II.

Usher syndrome is an autosomal recessive disorder characterised by retinitis pigmentosa and congenital sensorineural hearing loss. A gene for Usher syndrome type II (USH2) has been localised to chromosome 1q32-q41. DNA from a family with four of seven sibs affected with clinical characteristics of Usher syndrome type II was genotyped using markers spanning the 1q32-1q41 region. These included D1S70 and D1S81, which are believed to flank USH2. Genotypic results and subsequent linkage analysis indicated non-linkage of this family to these markers. The A test analysis for heterogeneity with this family and 32 other Usher type II families was statistically significant at p < 0.05. Further clinical evaluation of this family was done in light of the linkage results to determine if any phenotypic characteristics would allow for clinical identification of the unlinked type. No clear phenotypic differences were observed; however, this unlinked family may represent a previously unreported subtype of Usher type II characterised by a milder form of retinitis pigmentosa and mild vestibular abnormalities. Heterogeneity of Usher syndrome type II complicates efforts to isolate and clone Usher syndrome genes using linkage analysis and limits the use of DNA markers in early detection of Usher type II.

Background and Purpose: Management of dizziness and balance dysfunction is a major challenge after concussion. The purpose of this study was to examine the effect of vestibular rehabilitation in reducing dizziness and to improve gait and balance function in people after concussion. Methods: A retrospective chart review of 114 patients (67 children aged 18 years and younger [mean, 16 years; range, 8-18 years]; 47 adults older than 18 years [mean, 41 years; range, 19-73 years]) referred for vestibular rehabilitation after concussion was performed. At the time of initial evaluation and discharge, recordings were made of outcome measures of self-report (eg, dizziness severity, Activities-specific Balance Confidence Scale, and Dizziness Handicap Inventory) and gait and balance performance (eg, Dynamic Gait Index, gait speed, and the Sensory Organization Test). A mixed-factor repeated-measures analysis of variance was used to test whether there was an effect of vestibular rehabilitation therapy and age on the outcome measures. Results: The median length of time between concussion and initial evaluation was 61 days. Of the 114 patients who were referred, 84 returned for at least 1 visit. In these patients, improvements were observed in all self-report, gait, and balance performance measures at the time of discharge (P < .05). Children improved by a greater amount in dizziness severity (P = .005) and conditions 1 (eyes open, fixed support) and 2 (eyes closed, fixed support) of the Sensory Organization Test (P < .025). Discussion: Vestibular rehabilitation may reduce dizziness and improve gait and balance function after concussion. For most measures, the improvement did not depend on age, indicating that vestibular rehabilitation may equally benefit both children and adults. Conclusions: Vestibular rehabilitation should be considered in the management of individuals post concussion who have dizziness and gait and balance dysfunction that do not resolve with rest. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To validate a brief tool for screening migraine. BACKGROUND: Migraine is a common, but underdiagnosed condition. Effective utilization of nonphysician personnel to reliably screen patients for migraine may improve identification of migraineurs for clinical treatment and research. METHODS: An 8-question Migraine Assessment Tool (based on International Headache Society criteria) was designed for administration by a nurse with no specialized headache training as a pre-assessment for the diagnosis of migraine for use in either a research or clinical environment. A community sample of 80 adults (71 women, 9 men; mean age, 33.7 years; 80% white, 14% African American, 2.5% Asian American) with self-reported headache was recruited through advertisements. A headache specialist independently diagnosed subjects using clinical assessment, and a nurse who works in a balance disorder clinic used the Migraine Assessment Tool. Agreement between physician and nurse-administered Migraine Assessment Tool diagnoses was determined. Each subject returned in 2 to 4 weeks for a second assessment, administered by the same nurse. Agreement between the 2 diagnoses from the Migraine Assessment Tool was calculated. RESULTS: Comparison between diagnosis by the physician versus the Migraine Assessment Tool revealed a positive predictive value of 0.85; negative predictive value, 0.84; sensitivity, 0.89; specificity, 0.79; and observed agreement, 0.85. Cohen's kappa reliability measure was 0.69, indicating good test reliability. Interestingly, in 8 of the 12 cases of disagreement, the examiner diagnosing nonmigraine diagnosed analgesic overuse headache. Comparing diagnoses assigned by the 2 separate administrations of the Migraine Assessment Tool revealed a Cohen's kappa of 0.69. Notably, 9 of the 12 cases of nonagreement on the 2 assessments were due to subjects endorsing analgesic overuse in only 1 of the 2 testing sessions. CONCLUSIONS: This study showed good reliability and stability of a new, brief, nurse-administered migraine questionnaire. In addition, the study also showed that consistency in self-reporting analgesic overuse within individuals with headache is poor. This suggests the need for repeat questioning about analgesic overuse on subsequent appointments to ensure absence of analgesic overuse headache. [ABSTRACT FROM AUTHOR]

Galvanic stimulation produces a postural sway and eye movements in humans. Since galvanic currents are thought to exert their effect at the trigger zone of the vestibular nerve, an intact vestibular nerve should be necessary to produce a response. We have used galvanic stimulation in humans to test the hypothesis that intact vestibular nerve fibers are required to obtain a postural away response. Experimental subjects included normal subjects, patients who had undergone resection of an acoustic neuroma, and patients who had undergone vestibular neurectomy and surgical labyrinthectomy. Our results support the hypothesis that an intact vestibular nerve is necessary to produce a response. Moreover, two patients with recurrent vertigo following vestibular neurectomy and labyrinthectomy, who had absent ice-water caloric test responses in the operated ears, were found to have a positive galvanic response. This result suggested that their recurrent vertigo was based on intact residual vestibular nerve fibers. Although previous research has not yielded a routine clinical use for galvanic stimulation, our results suggest that galvanic stimulation of the vestibular system can provide unique and valuable diagnostic information. [ABSTRACT FROM AUTHOR]

The computerized rotational head impulse test (crHIT) uses a computer-controlled rotational chair to deliver whole-body rotational impulses to assess the semicircular canals. The crHIT has only been described for horizontal head plane rotations. The purpose of this study was to describe the crHIT for vertical head plane rotations. In this preliminary study, we assessed four patients with surgically confirmed unilateral peripheral vestibular abnormalities and two control subjects. Results indicated that the crHIT was well-tolerated for both horizontal head plane and vertical head plane stimuli. The crHIT successfully assessed each of the six semicircular canals. This study suggests that the crHIT has the potential to become a new laboratory-based vestibular test for both the horizontal and vertical semicircular canals.

Bipedal locomotion is naturally unstable and requires active control. Walking is believed to be primarily stabilized through the selection of foot placements; however, other strategies are available, including regulation of ankle inversion/eversion, ankle push-off, and angular momentum through trunk postural adjustments. The roles of these strategies in maintaining overall stability are often masked by the dominant foot placement strategy. The objectives of this study were to describe how the four strategies are used to respond to medial or lateral ground perturbations during overground walking in healthy individuals and determine reliance on each strategy. Fifteen healthy adults walked with and without perturbations applied to the right foot at heel strike while body kinematics and surface electromyographic activity were measured. Medial perturbations resulted in decreased step width on the first step after the perturbation, increased ankle inversion, increased ankle push-off, and rightward trunk sway. Lateral perturbations resulted in increased step width, decreased ankle inversion, no change in ankle push-off, and leftward trunk sway. EMG activity was consistent with the observed strategies (e.g. increased peroneus longus EMG activity during ankle eversion) with the exception of increased bilateral erector spinae activity for all perturbations. Foot placement was the dominant strategy in response to perturbations, with other strategies showing reduced, yet significant, roles. This work demonstrates that multiple strategies are recruited to improve the balance response in addition to foot placement alone. These results can serve as a reference for future studies of populations with impaired balance to identify potential deficits in strategy selection., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Objective: The purpose of this study was to establish the psychometric properties of the 9-Item Vestibular Activities Avoidance Instrument (VAAI-9), a patient-reported outcome measure developed to identify fear avoidance beliefs in persons with vestibular disorders., Methods: This prospective cohort study included 100 participants 18 years and older seeking care at a balance disorders clinic for dizziness. Participants completed the VAAI-9, the Dizziness Handicap Inventory (DHI), and other patient-reported outcomes at the initial visit and the 3-month follow-up. To measure test-retest reliability, the VAAI-9 was completed again 5 days after the initial visit and was analyzed using a 2-way mixed ICC for absolute agreement. Internal consistency was determined using the Cronbach alpha. The Spearman correlation coefficient was used to assess convergent validity of the VAAI-9 with other outcomes. Receiver operating characteristic curves were used to identify baseline VAAI-9 cutoff scores for those who reported mild (DHI ≤ 30) or moderate or severe (DHI > 30) perceived disability at the 3-month follow-up., Results: The mean age of the study cohort was 49 (SD = 16) years; 73 (73%) were women. Seventy-one participants completed the 5-day follow-up, and 68 completed the 3-month follow-up. The VAAI-9 demonstrated excellent internal consistency (α = 0.91) and test-retest reliability (ICC = 0.90). Baseline VAAI-9 scores had moderate to strong associations with other outcome measures at baseline and 3 months. A baseline VAAI-9 score of 26 or higher had a sensitivity of 80.6% and a specificity of 78.4% for identifying a DHI score of >30 at 3 months (area under the curve = 0.86)., Conclusions: The results provide evidence of excellent reliability and validity for the 9-item VAAI in persons with vestibular disorders. A baseline VAAI-9 score of ≥26 identified individuals at risk of persistent moderate to severe disability due to dizziness., Impact: Initial levels of fear avoidance beliefs measured using the VAAI-9 provided important prognostic information about outcomes for persons with vestibular symptoms., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background: The video head impulse test (vHIT) is a common assessment of semicircular canal function during high-speed impulses. Reliability of the vHIT for assessing vertical semicircular canals is uncertain. Vertical head impulses require a complex head movement, making it difficult to isolate a single semicircular canal and interpret resulting eye rotations., Objective: The purpose of this study was to provide descriptive head kinematics and vestibular stimuli during vertical plane impulses to ultimately improve impulse delivery and interpretation of vHIT results for vertical semicircular canals., Methods: Six participants received right anterior (RA) and left posterior (LP) semicircular canal impulses. Linear displacements, rotational displacements, and rotational velocities of the head were measured. Peak velocities in semicircular canal planes and peak-to-peak gravitoinertial accelerations at the otolith organs were derived from head kinematics., Results: The largest rotational velocities occurred in the target semicircular canal plane, with non-negligible velocities occurring in non-target planes. Larger vertical displacements and accelerations occurred on the right side of the head compared to the left for RA and LP impulses., Conclusions: These results provide a foundation for designing protocols to optimize stimulation applied to a singular vertical semicircular canal and for interpreting results from the vHIT for vertical semicircular canals.

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)., Competing Interests: All members of the Guideline Development Group and Advisory Board completed conflict of interest forms, which included information about grant funding, royalties, device/company shares, legal assistance, patents, device consultant/advocacy, publications, presentations, and clinical practice related to the Clinical Practice Guideline (CPG) topic. Forms were submitted to the Academy of Neurologic Physical Therapy (ANPT) Evidence-Based Documents Committee, who monitored and managed any identified perceived conflicts of interest. All recommendations were written as a group per standard CPG methodology. Therefore, no one individual made all the decisions. 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., (Copyright © 2021 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of Academy of Neurologic Physical Therapy, APTA.)

Background: A method for prescribing the difficulty or intensity of standing balance exercises has been validated in a healthy population, but requires additional validation in individuals with vestibular disorders., Objective: This study validated the use of ratings of perceived difficulty for estimation of balance exercise intensity in individuals with vestibular disorders., Methods: Eight participants with a confirmed diagnosis of a vestibular disorder and 16 healthy participants performed two sets of 16 randomized static standing exercises across varying levels of difficulty. Root Mean Square (RMS) of trunk angular velocity was recorded using an inertial measurement unit. In addition, participants rated the perceived difficulty of each exercise using a numerical scale ranging from 0 (very easy) to 10 (very difficult). To explore the concurrent validity of rating of perceived difficulty scale, the relationship between ratings of perceived difficulty and sway velocity was assessed using multiple linear regression for each group., Results: The rating of perceived difficulty scale demonstrated moderate positive correlations RMS of trunk velocity in the pitch (r = 0.51, p < 0.001) and roll (r = 0.73, p < 0.001) directions in participants with vestibular disorders demonstrating acceptable concurrent validity., Conclusions: Ratings of perceived difficulty can be used to estimate the intensity of standing balance exercises in individuals with vestibular disorders.

Context: Research in the area of dual-task paradigms to assess sport-related concussion (SRC) status is growing, but additional assessment of this paradigm in adolescents is warranted., Design: This case-control study compared 49 adolescent athletes aged 12-20 years with diagnosed SRC to 49 age- and sex-matched controls on visual-spatial discrimination and perceptual inhibition (PIT) reaction time tasks performed while balancing on floor/foam pad conditions., Methods: The SRC group completed measures at a single time point between 1 and 10 days postinjury. Primary outcomes were dual-task reaction time, accuracy, and sway. General linear models evaluated differences between groups (P < .05). Logistic regression identified predictors of concussion from outcomes. Area under the curve evaluated discriminative ability of identifying SRC., Results: Results supported significantly higher anterior-posterior (AP) sway values in concussed participants for visual-spatial discrimination and PIT when balancing on the floor (P = .03) and foam pad (P = .03), as well as mediolateral sway values on the floor during visual-spatial discrimination (P = .01). Logistic regression analysis (R2 = .15; P = .001) of all dual-task outcomes identified AP postural sway during the PIT foam dual task as the only significant predictor of concussed status (ß = -2.4; P = .004). Total symptoms (area under the curve = 0.87; P < .001) and AP postural sway on foam (area under the curve = 0.70; P = .001) differentiated concussed from controls., Conclusion: The AP postural sway on foam during a postural stability/PIT dual task can identify concussion in adolescents between 1 and 10 days from injury.

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., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Importance: Fear avoidance is a behavioral response to dizziness that can lead to chronic symptoms and maladaptation of the vestibular system, but there is no valid and reliable clinical measure of fear avoidance for persons with dizziness. Although the Vestibular Activities Avoidance Instrument (VAAI) was developed to identify fear avoidance beliefs in persons with dizziness, it was considered too long for clinical use., Objective: To continue development of the VAAI for clinical use by reducing its length and by assessing the internal consistency and construct validity through associations with measures of disability, quality of life, and psychological well-being., Design, Setting, and Participants: This prospective cohort study conducted from February 2018 to December 2019 at a tertiary care balance disorders clinic and in outpatient physical therapy clinics in the United States included 404 adults with dizziness., Main Outcomes and Measures: Participants completed the 81-item VAAI, the Vestibular Activities and Participation (VAP) measure, the 12-Item Short Form Health Survey (SF-12), and the Hospital Anxiety and Depression Scale (HADS) at baseline. Exploratory factor analysis of the VAAI was conducted to reduce the number of items. Internal consistency of the reduced VAAI was determined by calculating the Cronbach α. Convergent validity was assessed by examining the associations between the reduced VAAI and the VAP, the SF-12, and the HADS using Spearman correlation coefficients., Results: Data from 404 adults (mean [SD] age, 54.0 [17.0] years; 64.6% women) were included in the analyses. The exploratory factor analysis indicated that 2 factors explained the underlying constructs of the 81-Item VAAI. The first factor was retained and measured the construct of fear avoidance. The VAAI was reduced to 9 items (VAAI-9). The VAAI-9 showed excellent internal consistency (Cronbach α = 0.92) and was positively associated with the VAP (ρ = 0.81) and the HADS anxiety (ρ = 0.47) and depression (ρ = 0.64) subscales, and negatively associated with physical (ρ = -0.76) and mental (ρ = -0.47) health-related quality of life., Conclusions and Relevance: These findings indicate that the VAAI-9 is a short, internally consistent, valid measure of fear avoidance and is associated with quality of life, activity limitations and participation restrictions, and psychological well-being. The next steps in the development of the VAAI-9 will include validation in an external sample, assessment of test-retest validity, and prospective investigations of its association with future disability.

Background/objectives: Neuroimaging indicators of reduced brain health in the form of lower gray matter volume (GMV), lower fractional anisotropy (FA), and higher white matter hyperintensity volume (WMHV) have been related to global mobility measures, such as gait speed, in older adults. The purpose was to identify associations between brain regions and specific mobility functions to provide a greater understanding of the contribution of the central nervous system to independent living., Design: Cross-sectional study., Setting: Research laboratory., Participants: Seventy community-ambulating healthy older adults (mean age = 76 ± 5 years)., Measurements: Participants performed the following tests: gait speed, Five Times Sit to Stand, Four Square Step Test (FSST), and Dynamic Gait Index (DGI). Structural magnetic resonance imaging of each participant's brain was collected. Measures of regional GMV, tract-specific WMHV, and FA were extracted. Correlational analyses between the mobility measures and neuroimaging measures were conducted using whole brain and regional and tract-specific measures. This was followed by linear regression models relating the mobility measures to regions or tracts identified in the correlation analysis, and adjusting for age, sex, and body mass index., Results: Significant associations were found between higher GMV in multiple regions, primarily the parietal and temporal lobes, and better performance in gait speed, DGI, and FSST. After adjusting for personal factors, greater parahippocampus GMV was independently associated with greater gait speed. Greater inferior parietal lobe, supramarginal gyrus, and superior temporal gyrus GMVs were associated with gait function. Greater postcentral gyrus, parahippocampus, and superior temporal gyrus GMVs were associated with faster FSST performance. The WMHV and FA were not significantly correlated with the mobility measures., Conclusions: Gray matter regions associated with higher performance in mobility measures serving gait function and multidirectional stepping were those structures related to vestibular sensation, spatial navigation, and somatosensation. J Am Geriatr Soc 68:1023-1028, 2020., (© 2019 The American Geriatrics Society.)

Background and Purpose: Persons with vestibular disorders are known to have slower gait speed with greater imbalance and veering during dual-task walking than healthy individuals, but the cerebral mechanisms are unknown. The purpose of this study was to determine whether individuals with visual vertigo (VV) have different cerebral activation during dual-task walking compared with control subjects., Methods: Fourteen individuals with VV and 14 healthy controls (CON) were included (mean 39 years old, 85% women). A cross-sectional experimental study consisting of 4 combinations of 2 surfaces (even and uneven) and 2 task conditions (single- and dual-task) was performed. Participants walked over an even (level flooring) or uneven (wood prisms underneath carpeting) surface, either quietly or while reciting every other letter of the alphabet. Changes in cerebral activation over the bilateral prefrontal cortices were recorded using functional near-infrared spectroscopy during 4 task conditions relative to quiet standing. Gait speed and cognitive performance were recorded., Results: There were no between-group differences in cognitive performance. Both groups slowed when walking on an uneven surface or performing a dual-task; participants in the VV group walked more slowly than those in the CON group in all conditions. Participants with VV had decreased cerebral activation in the bilateral prefrontal regions in comparison to CON participants in all conditions., Discussion and Conclusions: Participants with VV had lower prefrontal cortex activation than CON participants during dual-task walking. Lower cortical activity in those with VV may be due to shifted attention away from the cognitive task to prioritize maintenance of dynamic balance.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A303).

This review will discuss the developmental, environmental, medical, psychological, visual, and other sensory-related factors that affect recovery after vestibular dysfunction. A general overview of the evidence for vestibular rehabilitation for patients with peripheral and central vestibular disorders is provided. Recent findings suggest that age, physical activity, certain congenital disorders, length of symptoms, musculoskeletal, visual and neuromuscular comorbidities, cognition, sleep, and medications are all factors that influence the effectiveness and outcome of vestibular rehabilitation. Psychological factors that also affect outcome include anxiety, depression, fear of movement, and fear of falling. Recovery in patients with vestibular disorders may be enhanced if the practitioner recognizes and attempts to remediate modifiable factors., Competing Interests: None., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Oculomotor impairments, dizziness, and imbalance are common after sports-related concussion (SRC) in adolescents and suggest a relationship between SRC and vestibular system dysfunction. However, it is not clear whether the source of these problems is attributable to the peripheral or central vestibular system., Hypothesis: The video Head Impulse Test (vHIT), which assesses peripheral vestibular function, will show differences in gain between adolescents with and without SRC. Furthermore, there will be an association between vHIT and clinical balance and vestibular/oculomotor testing., Study Design: Cross-sectional study., Level of Evidence: Level 2., Methods: Twenty-five symptomatic adolescents aged between 12 and 19 years with a recent (within 10 days) SRC and 22 healthy controls aged 13 to 20 years were assessed using the vHIT, Balance Error Scoring System (BESS), and Vestibular Ocular Motor Screening (VOMS) tools. The vestibulo-ocular reflex (VOR) gain was calculated independently for right and left head impulses. Independent-samples t tests or Mann-Whitney U tests for nonnormal distributions were used to compare concussed patients and controls on the measures. Spearman rank-order correlations were used to assess the association of vHIT with BESS and VOMS., Results: VOR gain in all adolescents with SRC was greater than 0.8, which is considered within normal limits. VOR gain and BESS scores were not significantly different between groups. Adolescents with SRC had significantly worse VOMS item scores than adolescents without SRC ( P < 0.001). There were no significant correlations among vHIT gain and VOMS or BESS., Conclusion: There was no evidence for dysfunction in the peripheral horizontal semicircular canal function at high rotation speeds (ie, vHIT) after SRC, and vHIT was unrelated to balance and vestibular/oculomotor symptoms and dysfunction. However, adolescents with SRC scored worse on vestibular and oculomotor testing than those without SRC. Vestibular dysfunction and symptoms after SRC may be centrally derived., Clinical Relevance: We do not recommend the assessment of head impulse function in adolescents with SRC unless more definitive signs of peripheral vestibular injury are present. We recommend using the VOMS to assess symptoms of suspected SRC injury in adolescents.

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., (© 2019 American Physical Therapy Association.)

The reliability of balance exercises performance in experimental and clinical studies has typically been confined to a small set of exercises. In order to advance the field of assessing balance exercise intensity, establishing the reliability of performance during a more diverse array of exercises should be undertaken. The purpose of this study was to investigate the test-retest reliability of postural sway produced during performance of 24 different balance tasks, and to evaluate the reliability of different measures of postural sway. Sixty-two healthy subjects between the ages of 18 and 85 years of age (50% female, mean age 55 ± 20 years) participated. Subjects were tested during two visits one week apart and performed two sets of the 24 randomized standing tasks per visit. The tasks consisted of combinations of the following factors: surface (firm and foam), vision (eyes open and eyes closed), stance (feet apart and semi-tandem), and head movement (no movement, yaw, and pitch). Angular position displacement, angular velocity, and linear acceleration postural sway in the pitch and roll planes was recorded via an inertial measurement unit. The postural sway measures demonstrated at fair to good test-retest reliability with few exceptions, and angular velocity measures demonstrated the greatest reliability. The between-visit reliability of two averaged trials was excellent for most tasks. The study indicates that performance of most balance tasks used as part of balance rehabilitation is reliable, and quantitative assessment could be used to document change.

Changes in cognition due to age have been associated with falls and reduced standing postural control. Sensory integration is one component of postural control that may be influenced by certain aspects of cognitive functioning. This study investigated associations between measures of cognitive function and sensory integration capabilities for healthy young and older adults. Dynamic posturography was performed using the Equitest Sensory Organization Test (SOT) protocol to evaluate sensory integration during standing using sway-referencing of the platform and/or visual scene to alter somatosensory and visual inputs. The Equilibrium Score was used as a measure of sway. Cognitive testing examined aspects of cognitive function that have been associated with falls in older adults. A correlational analysis investigated associations between the cognitive measures and postural sway during the altered sensory conditions of the SOT. For older subjects only, slower decision-processing speed was associated with increased sway during SOT conditions whenever somatosensation was altered. Reduced perceptual inhibition was associated with increased sway whenever somatosensation was intact, and particularly when vision was altered in the presence of somatosensation. Visuospatial construct ability was associated with sway only when the eyes were closed during altered somatosensation. Task-switching was associated with sway only when vision and somatosensation were intact. With increased age, deficits in decision speed and inhibition appear associated with the sensory integration crucial for balance maintenance. Associations are modulated by the availability of somatosensation and vision. These associations define situations and individual differences in aspects of cognition that may relate to situational loss of balance in older adults.

Objective: To investigate the magnitude of postural sway induced by different balance tasks in adolescents with concussion and to examine the associations of postural sway with concussion symptoms., Design: Cross-sectional study., Patients or Other Participants: Fifty-six adolescents (20 girls, 36 boys) between 13 and 17 years of age who sustained a concussion within the past 44 days and were still symptomatic., Main Outcome Measure(s): Anterior-posterior postural sway was measured using an accelerometer attached to the participant's lower back while he or she performed 6 static-balance tasks that varied the visual input, type of surface, and foot stance. Participants self-reported symptoms that occurred at the time of the concussion (eg, dizziness, confusion, amnesia) as well as at the time of balance testing (eg, eye and head movement-induced dizziness)., Results: The normalized path length of postural sway during the different balance tasks was greater with the eyes closed (mean = 19.3 mG/s) compared with the eyes open (mean = 12.4 mG/s; P < .001). Furthermore, sway while standing with the feet together on a foam surface (mean = 17.9 mG/s) or while tandem standing on a firm surface (mean = 19.4 mG/s) was greater than sway while standing with the feet together on a firm surface (mean = 10.3 mG/s; P < .001). Greater sway was associated with dizziness and confusion reported at the time of injury ( P < .05). Dizziness and headache symptoms at rest were positively correlated with sway ( P < .05)., Conclusions: Using accelerometers to measure postural sway during different challenging balance conditions in adolescents with concussion may provide an objective means of quantifying balance impairments in clinical environments. Furthermore, the association of these measurements with symptoms suggests a need to account for symptom severity at the time of testing.

Background: Concussion can cause vestibular dysfunction and oculomotor abnormalities which can lead to dizziness and protracted recovery time. There are few clinically useful, functional measures of the vestibulo-ocular reflex (VOR) post-concussion., Purpose: The purpose of this study was to examine the gaze stabilization test (GST) in those referred for vestibular physical therapy following concussion, to determine the association between GST and other measures of recovery following concussion, and to examine the effect of demographic variables on GST performance., Research Design: Retrospective chart review., Study Sample: One hundred fifty-eight individuals who sustained a concussion and were referred to vestibular physical therapy., Data Collection and Analysis: Horizontal and vertical GST scores (HGST and VGST), neurocognitive testing results, and demographic data were extracted retrospectively from the patient health record. Correlations between GST velocity and neurocognitive test results and between GST and patient-reported outcomes were examined. Differences in GST performance among patient subgroups were examined using one-way analysis of variance., Results: Subjects included individuals aged 12 to 43 years (mean = 20, standard deviation [SD] = 7), with most having sport-related concussion (67%). The mean time from injury to GST was 215 days (SD = 241) and the mean time from physical therapy evaluation to GST was 48 days (SD = 54). HGST and VGST had a weak positive correlation to the Activities-Specific Balance Confidence Scale (r = 0.20, r = 0.21) and weak negative correlation to the Dizziness Handicap Inventory (r = -0.18, r = -0.22). HGST had a weak positive correlation to the visual motor processing speed domain of the immediate post-concussion assessment and cognitive test (r = 0.20). Male patients achieved significantly higher velocities than female patients on HGST and VGST (p = 0.02, p = 0.01)., Conclusions: The present study details the use of GST in patients with concussion and demonstrates an association with common outcome measures in vestibular rehabilitation. Results indicate that patients who achieved higher velocities on GST perceived lower handicap due to dizziness and had higher confidence in their balance. GST may be a relevant test of VOR in this population, as it is a more functional test of the VOR required for sports. Future work is needed to further evaluate the role of GST in concussion management., (American Academy of Audiology.)

Background and Purpose: Individuals with visual vertigo (VV) describe symptoms of dizziness, disorientation, and/or impaired balance in environments with conflicting visual and vestibular information or complex visual stimuli. Physical therapists often prescribe habituation exercises using optic flow to treat these symptoms, but it is not known how individuals with VV process the visual stimuli. The primary purpose of this study was to use functional near-infrared spectroscopy (fNIRS) to determine if individuals with VV have different cerebral activation during optic flow compared with control subjects., Methods: Fifteen individuals (5 males and 10 females in each group) with VV seeking care for dizziness and 15 healthy controls (CON) stood in a virtual reality environment and viewed anterior-posterior optic flow. The support surface was either fixed or sway-referenced. Changes in cerebral activation were recorded using fNIRS during periods of optic flow relative to a stationary visual environment. Postural sway of the head and center of mass was recorded using an electromagnetic tracker., Results: Compared with CON, the VV group displayed decreased activation in the bilateral middle frontal regions when viewing optic flow while standing on a fixed platform. Despite both groups having significantly increased activation in most regions while viewing optic flow on a sway-referenced surface, the VV group did not have as much of an increase in the right middle frontal region when viewing unpredictable optic flow in comparison with the CON group., Discussion and Conclusions: Individuals with VV produced a pattern of reduced middle frontal cerebral activation when viewing optic flow compared with CON. Decreased activation in the middle frontal regions of the cerebral cortex may represent an alteration in control over the normal reciprocal inhibitory visual-vestibular interaction in visually dependent individuals. Although preliminary, these findings add to a growing body of literature using functional brain imaging to explore changes in cerebral activation in individuals with complaints of dizziness, disorientation, and unsteadiness. Future studies in larger samples should explore if this decreased activation is modified following a rehabilitation regimen consisting of visual habituation exercises.

Hypothesis: People with unilateral vestibular hypofunction (UVH) would have increased postural sway and slower reaction times while using vibrotactile feedback (VTF) during dual-task conditions compared with age-matched controls., Background: VTF has been shown to improve real-time balance performance in persons with vestibular disorders. Future use of this technology outside of the laboratory environment as a real-time balance aid requires that using VTF during dual-tasking scenarios be studied., Method: Nine people with UVH and nine age-matched controls participated in a study focused on assessing the effects of a secondary cognitive task and sensory integration conditions on the root-mean-square of center of pressure (RMS COP) while using VTF. Reaction times from the secondary cognitive task were used to assess the effects of VTF, and sensory integration conditions on the attention required to perform the task., Results: The results showed that there was no group difference between individuals with UVH and age-matched controls on balance performance while using VTF during dual-task conditions. Using VTF significantly degraded the reaction time performance in both groups, and the participants with UVH had slower reaction times compared with controls., Conclusion: People with UVH showed the ability to use VTF to control balance during dual-task conditions, but more attentional resources were needed to perform the secondary cognitive tasks while using VTF.

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Background and Purpose: Individuals with visual vertigo describe symptoms of dizziness, disorientation, and/or impaired balance in environments with conflicting visual and vestibular information or complex visual stimuli. Physical therapists often prescribe habituation exercises using optic flow to treat these symptoms, but there are no evidence-based guidelines for delivering optic flow and it is unclear how the brain processes such stimuli. The purposes of this study were to use functional near-infrared spectroscopy (fNIRS) to explore cerebral activation during optic flow, and determine if visual fixation had a modulating effect on brain activity., Methods: Fifteen healthy participants (7 males and 8 females; mean age 41 years old) stood in a virtual reality environment and viewed optic flow moving unidirectionally in the yaw plane with and without fixation. Changes in cerebral activation were recorded from the bilateral fronto-temporo-parietal and occipital lobes using fNIRS., Results: Cerebral activation was greater with visual motion than while viewing a stationary scene. Greater cerebral activation in the bilateral fronto-temporo-parietal lobes was observed when optic flow was viewed with fixation., Discussion and Conclusions: Optic flow activates the bilateral fronto-temporo-parietal regions of the cerebral cortex. This activation is greater while viewing optic flow and a fixation target, providing preliminary evidence supporting the use of a fixation target during habituation exercises.

Aims: Inhibition associated with perception has been implicated in sensory integration processes for balance when sensory conflict occurs. The current study examines the associations of three measures of inhibition (perceptual inhibition, motor inhibition, and Stroop interference) with standing balance under sensory conflict conditions in younger and older adults., Methods: Perceptual inhibition, motor inhibition, and Stroop interference were measured in younger and older subjects. Standing balance under conditions of sensory conflict was evaluated using a modified dynamic posturography protocol. Correlative analysis was performed to examine the associations between the inhibition measures and sway., Results: In older adults only, perceptual inhibition was correlated with sway when sensory conflict was present. Stroop interference and motor inhibition were not significantly correlated with sway under any posturography conditions., Conclusion: Measures of perceptual inhibition are associated with reduced sensory integration capability for balance during sensory conflict conditions in older adults., (© 2018 S. Karger AG, Basel.)