Vestibular function assessment using the NIH Toolbox

Effect of vestibular loss on head-on-trunk stability in individuals with vestibular schwannoma

The vestibulo-collic reflex generates neck motor commands to produce head-on-trunk movements that are essential for stabilizing the head relative to space. Here we examined the effects of vestibular loss on head-on-trunk kinematics during voluntary behavior. Head and trunk movements were measured in individuals with vestibular schwannoma before and then 6 weeks after unilateral vestibular deafferentation via surgical resection of the tumor. Movements were recorded in 6 dimensions (i.e., 3 axes of rotation and 3 axes of translation) using small light-weight inertial measurement units while participants performed balance and gait tasks. Kinematic measures differed between individuals with vestibular schwannoma (at both time points) and healthy controls for the more challenging exercises, namely those performed in tandem position or on an unstable surface without visual input. Quantitative assessment of the vestibulo-ocular reflex (VOR) revealed a reduction in VOR gain for individuals with vestibular schwannoma compared to control subjects, that was further reduced following surgery. These findings indicated that the impairment caused by either the tumor or subsequent surgical tumor resection altered head-on-trunk kinematics in a manner that is not normalized by central compensation. In contrast, we further found that head-on-trunk kinematics in individuals with vestibular schwannoma were actually comparable before and after surgery. Thus, taken together, our results indicate that vestibular loss impacts head-on-trunk kinematics during voluntary balance and gait behaviors, and suggest that the neural mechanisms mediating adaptation alter the motion strategies even before surgery in a manner that may be maladaptive for long-term compensation.

Assessing the Effects of Mild Traumatic Brain Injury on Vestibular Home Exercise Performance with Wearable Sensors

After a mild traumatic brain injury (mTBI), dizziness and balance problems are frequently reported, affecting individuals' daily lives and functioning. Vestibular rehabilitation is a standard treatment approach for addressing these issues, but its efficacy in this population remains inconclusive. A potential reason for suboptimal outcomes is the lack of objective monitoring of exercise performance, which is crucial for therapeutic success. This study utilized wearable inertial measurement units (IMUs) to quantify exercise performance in individuals with mTBI during home-based vestibular rehabilitation exercises. Seventy-three people with mTBI and fifty healthy controls were enrolled. Vestibular exercises were performed, and IMUs measured forehead and sternum velocities and range of motions. The mTBI group demonstrated a slower forehead peak angular velocity in all exercises, which may be a compensatory strategy to manage balance issues or symptom exacerbation. Additionally, the mTBI group exhibited a larger forehead range of motion during specific exercises, potentially linked to proprioceptive deficits. These findings emphasize the usefulness of utilizing IMUs to monitor the quality of home-based vestibular exercises for individuals with mTBI and the potential for IMUs improving rehabilitation outcomes.

The effects of vestibular dysfunction on balance and self-concept in children with cochlear implants

OBJECTIVES

Children with cochlear implants (CCI) have an increased rate of vestibular dysfunction. Vestibular dysfunction is associated with decreased balance and dynamic visual acuity ability. Hearing loss alone is associated with reduced speech perception and vocabulary in children. In adults, vestibular dysfunction is associated with reduced quality of life; however, similar relationships have not been studied in children with vestibular dysfunction. Therefore, the objective of the present study was to evaluate the effect of hearing loss and vestibular dysfunction on self-concept in CCI (n = 33) compared to children with normal hearing (CNH, n = 38). It was hypothesized that children with vestibular dysfunction would have reduced self-concept beyond that from hearing loss, secondary to the presence of balance and visual acuity deficits.

METHODS

The Piers-Harris Children's Self-Concept Scale - 2, speech perception, vocabulary, video head impulse test (vHIT), rotary chair, balance using the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2), and dynamic visual acuity (DVA) testing were completed on all participants.

RESULTS

In the 34 CCI, 24 had normal vestibular function, 6 had unilateral vestibular dysfunction, and 4 had bilateral vestibular dysfunction. There were no significant mean differences in the Piers-Harris Children's Self-Concept Scale - 2 between groups. A Principal Component Analysis (PCA) was conducted on the predictor variables (average horizontal canal vHIT gain, BOT-2 score, DVA, speech perception, and vocabulary) resulting in two factors; factor 1 represented "vestibular" components (vHIT, BOT-2, and DVA) and factor 2 represented "auditory-language" components (speech perception and vocabulary). In addition to age and gender, the 2 PCA factors were analyzed using multivariate regression with stepwise selection to determine which factors best predicted self-concept. The PCA auditory-language factor was the only significant predictor of self-concept.

CONCLUSIONS

Auditory-language, not vestibular related factors, contribute to the self-concept of CCI. While adults with vestibular dysfunction have reduced quality of life, it could be that children with vestibular dysfunction have some psychosocial resilience.

Atypical vocal quality in women with the FMR1 premutation: an indicator of impaired sensorimotor control

Women with the FMR1 premutation are susceptible to motor involvement related to atypical cerebellar function, including risk for developing fragile X tremor ataxia syndrome. Vocal quality analyses are sensitive to subtle differences in motor skills but have not yet been applied to the FMR1 premutation. This study examined whether women with the FMR1 premutation demonstrate differences in vocal quality, and whether such differences relate to FMR1 genetic, executive, motor, or health features of the FMR1 premutation. Participants included 35 women with the FMR1 premutation and 45 age-matched women without the FMR1 premutation who served as a comparison group. Three sustained /a/ vowels were analyzed for pitch (mean F0), variability of pitch (standard deviation of F0), and overall vocal quality (jitter, shimmer, and harmonics-to-noise ratio). Executive, motor, and health indices were obtained from direct and self-report measures and genetic samples were analyzed for FMR1 CGG repeat length and activation ratio. Women with the FMR1 premutation had a lower pitch, larger pitch variability, and poorer vocal quality than the comparison group. Working memory was related to harmonics-to-noise ratio and shimmer in women with the FMR1 premutation. Vocal quality abnormalities differentiated women with the FMR1 premutation from the comparison group and were evident even in the absence of other clinically evident motor deficits. This study supports vocal quality analyses as a tool that may prove useful in the detection of early signs of motor involvement in this population.

Advances in dynamic visual acuity test research

The dynamic visual acuity test (DVAT) is a functional evaluation tool for the impairment and compensation of the vestibular system, which could reflect the Vestibulo-ocular reflex (VOR) function. We present an overview of DVAT research, displaying recent advances in test methods, application, and influencing factors; and discussing the clinical value of DVAT to provide a reference for clinical application. There are two primary types of DVAT: dynamic-object DVAT and static-object DVAT. For the latter, in addition to the traditional bedside DVAT, there are numerous other approaches, including Computerized DVAT (cDVAT), DVAT on a treadmill, DVAT on a rotary, head thrust DVA (htDVA) and functional head impulse testing (fHIT), gaze shift dynamic visual acuity with walking (gsDVA), translational dynamic visual acuity test (tDVAT), pediatric DVAT. The results of DAVT are affected by subject [occupation, static visual acuity (SVA), age, eyeglass lenses], testing methods, caffeine, and alcohol. DVAT has numerous clinical applications, such as screening for vestibular impairment, assessing vestibular rehabilitation, predicting fall risk, and evaluating ophthalmology-related disorders, vestibular disorders, and central system disorders.

Baseline characterization of the ARMADA (Assessing Reliable Measurement in Alzheimer's Disease) study cohorts

INTRODUCTION

The National Institutes of Health (NIH) Toolbox (NIHTB) provides computerized measures of cognition, emotion, sensation, and motor abilities across the lifespan. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study validated the NIHTB in individuals across the cognitive aging spectrum. This article reports the characteristics of our sample of participants.

METHODS

Participants were recruited across nine sites and classified clinically as cognitively normal (NC), with mild cognitive impairment (MCI), or with dementia of the Alzheimer's type (DAT.) They completed the NIHTB at multiple time points and many had at least one Alzheimer's biomarker previously obtained.

RESULTS

Groups differed with respect to dementia severity levels, as anticipated, but were well-matched across many demographic characteristics.

DISCUSSION

The ARMADA study demographics and baseline characteristics provide a suitable sample for validating the NIHTB across the cognitive aging spectrum. Other enriched samples (African American participants, Spanish NIHTB, 85+ years of age) will be reported elsewhere.

HIGHLIGHTS

There is a need for assessments that can detect the early stages of cognitive decline in older adults. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study will validate the National Institutes of Health (NIH) Toolbox across the aging spectrum, including mild cognitive impairment (MCI) and dementia of the Alzheimer's type (DAT). Here we report the characteristics of participants. Groups were well-matched across most demographic characteristics, and clinical characteristics differed as expected. ARMADA study cohorts reflect their respective clinical syndromes for validating the NIH Toolbox.

Characterization of Balance Control and Postural Stability in Patients With Alzheimer Disease

Balance in Alzheimer disease (AD) patients is not rigorously understood. In this study, we characterize balance using qualitative [Berg Balance Scale (BBS)] and quantitative measures (posturography) and assess relationships between qualitative and quantitative balance measures in AD. Patients with mild-moderate AD (n=48) were recruited. BBS scores and posturography metrics, including medial-lateral sway range, anterior-posterior sway range, sway area, and sway velocity, were assessed in eyes-open and eyes-closed conditions. Adjusted linear regressions were used to assess relationships between posturography and BBS score. Mean BBS score was 50.4±5.3. In eyes-open conditions, posturography and BBS score were not significantly associated. In eyes-closed conditions, better BBS score was significantly associated with lower sway area (β=-0.91; P =0.006). Better scores of BBS items involving turning and reduced base of support were associated with greater eyes-closed sway area. Posturography in the more challenging eyes-closed condition may predict functional balance deficits in AD patients.

Rating of perceived difficulty scale for measuring intensity of standing balance exercises in individuals with vestibular disorders

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.

Head movement kinematics are altered during balance stability exercises in individuals with vestibular schwannoma

Background

Balance stabilization exercises are often prescribed to facilitate compensation in individuals with vestibular schwannoma (VS). However, both the assessment and prescription of these exercises are reliant on clinical observations and expert opinion rather than on quantitative evidence. The aim of this study was to quantify head motion kinematics in individuals with vestibular loss while they performed commonly prescribed balance stability exercises.

Methods

Using inertial measurement units, head movements of individuals with vestibular schwannoma were measured before and after surgical deafferentation and compared with age-matched controls.

Results

We found that individuals with vestibular schwannoma experienced more variable head motion compared to healthy controls both pre- and postoperatively, particularly in absence of visual input, but that there was little difference between preoperative and postoperative kinematic measurements for our vestibular schwannoma group. We further found correlations between head motion kinematic measures during balance exercises, performed in the absence of visual input, and multiple clinical measurements for preoperative VS subjects. Subjects with higher head motion variability also had worse DVA scores, moved more slowly during the Timed up and Go and gait speed tests, and had lower scores on the functional gait assessment. In contrast, we did not find strong correlations between clinical measures and postoperative head kinematics for the same VS subjects.

Conclusions

Our data suggest that further development of such metrics based on the quantification of head motion has merit for the assessment and prescription of balance exercises, as demonstrated by the calculation of a “kinematic score” for identifying the most informative balance exercise (i.e., “Standing on foam eyes closed”).

ARMADA: Assessing reliable measurement in Alzheimer's disease and cognitive aging project methods

INTRODUCTION

Early detection of cognitive decline in older adults is a public health priority. Advancing Reliable Measurement in Alzheimer's Disease and Cognitive Aging (ARMADA), a multisite study, is validating cognition, emotion, motor, and sensory modules of the National Institutes of Health Toolbox for Assessment of Neurological and Behavioral Function (NIHTB) in the aging spectrum from cognitively normal to dementia of the Alzheimer's type (DAT).

METHODS

Participants 65 to 85 years old, in demographic groups racially proportional to the general US population, are recruited in one of three groups to validate the NIHTB: cognitively normal, amnestic mild cognitive impairment (aMCI), or mild DAT. Additional special emphasis cohorts include (1) Blacks in the three clinical groups; (2) Spanish-speakers in the three clinical groups; (3) cognitively normal, population-proportional, over age 85.

DISCUSSION

Longitudinal study will determine whether NIHTB can predict cognitive decline and is associated with Alzheimer's disease biomarkers. Here, we detail the methods for the ARMADA study.

Does vestibular loss result in cognitive deficits in children with cochlear implants?

BACKGROUND

In adults, vestibular loss is associated with cognitive deficits; however, similar relationships have not been studied in children.

OBJECTIVE

Evaluate the effect of vestibular loss on working memory and executive function in children with a cochlear implant (CCI) compared to children with normal hearing (CNH).

METHODS

Vestibular evoked myogenic potential, video head impulse, rotary chair, and balance testing; and the following clinical measures: vision, hearing, speech perception, language, executive function, and working memory.

RESULTS

Thirty-eight CNH and 37 CCI participated (26 with normal vestibular function, 5 with unilateral vestibular loss, 6 with bilateral vestibular loss). Children with vestibular loss demonstrated the poorest balance performance. There was no significant reduction in working memory or executive function performance for either CCI group with vestibular loss; however, multivariate regression analysis suggested balance performance was a significant predictor for several working memory subtests and video head impulse gain was a significant predictor for one executive function outcome.

CONCLUSIONS

CCI with vestibular loss did not have significantly reduced working memory or executive function; however, balance performance was a significant predictor for several working memory subtests. Degree of hearing loss should be considered, and larger sample sizes are needed.

Using Functional Outcomes to Predict Vestibular Loss in Children

OBJECTIVE

The purpose of this study was to determine: (1) the relationship between vestibular loss severity and functional performance, (2) which functional performance outcomes best predict vestibular loss, and (3) which vestibular rate sensors (canals vs. otoliths) provide the most weighting during different functional measures.

STUDY DESIGN

Prospective.

SETTING

Tertiary referral center.

PATIENTS

Fifty-seven children with normal hearing (mean age: 12.3 years, 32 males) and 55 children with cochlear implants (mean age 12.8 years, 29 males).

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Video head impulse test, cervical vestibular evoked myogenic potential (cVEMP), ocular VEMP (oVEMP), single leg stance, Standing Balance Test, active and passive dynamic visual acuity, and the balance subtest of the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2).

RESULTS

Performance worsened as vestibular loss severity worsened for all functional outcomes except the standing balance test conditions 1 and 2. The best outcomes for classifying children with vestibular loss were the single leg stance (cut-off criterion: 5 seconds; sensitivity and specificity of 88% and 86%) and the BOT-2 balance subtest (cut-off criterion of 27.5 points; sensitivity and specificity of 88% and 88%). Average horizontal canal vHIT gain was a significant predictor of all functional outcomes while neither corrected cVEMP amplitude nor oVEMP amplitude predicted performance.

CONCLUSION

Functional performance declines as vestibular loss severity worsens. Single leg stance is fast and efficient for predicting vestibular loss in school age children. Average horizontal canal vHIT best predicts functional performance; if using a tiered approach, horizontal canal vHIT should be completed first.

NCS Assessments of the Motor, Sensory, and Physical Health Domains

As part of the National Children's Study (NCS) comprehensive and longitudinal assessment of the health status of the whole child, scientific teams were convened to recommend assessment measures for the NCS. This manuscript documents the work of three scientific teams who focused on the motor, sensory, or the physical health aspects of this assessment. Each domain team offered a value proposition for the importance of their domain to the health outcomes of the developing infant and child. Constructs within each domain were identified and measures of these constructs proposed. Where available extant assessments were identified. Those constructs that were in need of revised or new assessment instruments were identified and described. Recommendations also were made for the age when the assessments should take place.

Characterizing gaze and postural stability deficits in people with multiple sclerosis

BACKGROUND

People with Multiple Sclerosis (PwMS) experience a wide range of symptoms that can alter function and limit activity and community participation. Symptoms including sensory changes, weakness, fatigue and others have been well documented. However, symptoms related to changes in vestibular related function, including gaze and postural stability have not been fully explored. While some recent studies have begun to provide insight into these deficits in PwMS and have explored the use of rehabilitation paradigms for their management, much remains unknown about the full extent of these deficits. Therefore, this study aimed to characterize the presence of gaze and postural stability deficits in measures across the World Health Organization International Classification of Functioning, Disability, and Health (WHO ICF) and to examine how deficits in domains of body structure and function and activity contribute to participation level limitations.

METHODS

Baseline data from 41 PwMS (mean(SD) age = 53.9(11.2), 78% female) enrolled as part of a randomized clinical trial were used in this analysis. Measures of gaze and postural stability from the ICF domains of body structure and function (Vestibular ocular reflex [VOR] gain and postural sway area), activity (computerized dynamic visual acuity [cDVA] and MiniBEST test), and participation (Dizziness handicap inventory [DHI] and Activities Balance Confidence [ABC] scale) along with demographic data were used to characterize the sample. To explore relationships between ICF domains for gaze and postural stability, univariate correlations were performed between measures from each domain using Pearson's correlations. Separate multivariate regression models examined how measures from the body structure and function and activity domains contributed to the variance in the participation level outcomes. Variance explained by the models was quantified using R-squared statistic and contribution of the independent variables were quantified using the beta coefficient (p < 0.05).

RESULTS

Correlation analysis demonstrated significant relationships in the postural stability measures across domains. Specifically, between postural sway area on a firm surface and MiniBEST test score (r = -.48;p < 0.01) and MiniBEST test score and ABC score (r = 0.5;p < 0.01). Significant correlations were also found between the gaze stability measures of horizontal and vertical VOR gain (r = .68;p < 0.001), horizontal VOR gain and dynamic visual acuity (r = .38;p = 0.02), and vertical VOR gain and dynamic visual acuity (r = .54;p < 0.001). Regression models assessing postural stability, found that only the MiniBEST score significantly contributed to the variance in ABC score (p = 0.01) and the full model explained 34% of the variance in ABC score. Regression modeling of gaze stability outcomes did not produce any variable that significantly contributed to the variance in DHI score and the full model explained 18% of the variance in DHI score.

CONCLUSIONS

PwMS in this sample demonstrated deficits in gaze and postural stability across the domains of the WHO ICF compared to past samples of PwMS and healthy cohorts. Correlation between measures in the different domains were present, but no strong relationship between measures of body structure and function, activity and participation level outcomes were observed. This lack of relationship across the domains is likely contributed to the relatively small sample size, the high level of variability observed in the outcomes, and the diverse presentation often seen in PwMS.

Gait Difficulties and Postural Instability in Adrenoleukodystrophy

Background: Gait and balance difficulties are among the most common clinical manifestations in adults with X-linked adrenoleukodystrophy, but little is known about the contributions of sensory loss, motor dysfunction, and postural control to gait dysfunction and fall risk.

Objective: To quantify gait and balance deficits in both males and females with adrenoleukodystrophy and evaluate how environmental perturbations (moving surfaces and visual surrounds) affect balance and fall risk.

Methods: We assessed sensory and motor contributions to gait and postural instability in 44 adult patients with adrenoleukodystrophy and 17 healthy controls using three different functional gait assessments (25 Foot Walk test, Timed Up and Go, and 6 Minute Walk test) and computerized dynamic posturography.

Results: The median Expanded Disability Status Scale score for the patient cohort was 3.0 (range 0.0–6.5). Both males and females with adrenoleukodystrophy showed impairments on all three functional gait assessments relative to controls (P < 0.001). Performance on walking tests and Expanded Disability Status Scale scores correlated with incidence of falls on computerized dynamic posturography, with the 25 Foot Walk being a moderately reliable predictor of fall risk (area under the ROC curve = 0.7675, P = 0.0038).

Conclusion: We demonstrate that gait difficulties and postural control deficits occur in patients with adrenoleukodystrophy, albeit at an older age in females. Postural deficits were aggravated by eyes closed and dynamic conditions that rely on vestibular input, revealing challenges to the interplay of motor, sensory and vestibular circuitry in adrenoleukodystrophy.

Turning Toward Monitoring of Gaze Stability Exercises: The Utility of Wearable Sensors

BACKGROUND AND PURPOSE

Few tools are currently available to quantify gaze stability retraining exercises. This project examined the utility of a head-worn inertial measurement unit (IMU) to quantify head movement frequency, velocity, and amplitude during gaze stability exercises.

METHODS

Twenty-eight individuals with multiple sclerosis and complaints of dizziness or a history of falls were randomly assigned to either a strength and aerobic exercise (SAE) or gaze and postural stability (GPS) group. During a 6-week intervention, participants wore a head-mounted IMU 3 times (early, middle, and late). For aim 1, the frequency, mean peak velocity, and mean peak amplitude of head turns during equivalent duration components of group-specific exercises were compared using general linear models. For aim 2, the progression of treatment in the GPS group was examined using general linear regression models for each outcome.

RESULTS

Aim 1 revealed the GPS group demonstrated significantly greater velocity and amplitude head turns during treatment than the SAE group. The frequency of head turns did not significantly differ between the 2 groups. The aim 2 analyses demonstrated that the yaw and pitch frequency of head turns significantly increased during gaze stability exercises over the 6-week intervention. Velocity and amplitude of head turns during yaw and pitch gaze stability exercises did not significantly change.

DISCUSSION AND CONCLUSIONS

A head-worn IMU during rehabilitation distinguished between groups. Furthermore, within the GPS group, the IMU quantified the progression of the frequency of head movements during gaze stability exercises over time.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A320).

Head movement kinematics are altered during gaze stability exercises in vestibular schwannoma patients

Gaze stability is the ability of the eyes to fixate a stable point when the head is moving in space. Because gaze stability is impaired in peripheral vestibular loss patients, gaze stabilization exercises are often prescribed to facilitate compensation. However, both the assessment and prescription of these exercises are subjective. Accordingly, here we quantified head motion kinematics in patients with vestibular loss while they performed the standard of care gaze stability exercises, both before and after surgical deafferentation. We also correlate the head kinematic data with standard clinical outcome measures. Using inertial measurement units, we quantified head movements in patients as they transitioned through these two vestibular states characterized by different levels of peripheral damage. Comparison with age-matched healthy control subjects revealed that the same kinematic measurements were significantly abnormal in patients both pre- and post-surgery. Regardless of direction, patients took a longer time to move their heads during the exercises. Interestingly, these changes in kinematics suggest a strategy that existed preoperatively and remained symmetric after surgery although the patients then had complete unilateral vestibular loss. Further, we found that this kinematic assessment was a good predictor of clinical outcomes, and that pre-surgery clinical measures could predict post-surgery head kinematics. Thus, together, our results provide the first experimental evidence that patients show significant changes in head kinematics during gaze stability exercises, even prior to surgery. This suggests that early changes in head kinematic strategy due to significant but incomplete vestibular loss are already maladaptive as compared to controls.

Assessing Physical Function and Mobility following Pediatric Traumatic Brain Injury with the NIH Toolbox Motor Battery: A Feasibility Study

AIMS

Traumatic brain injury (TBI) can impair physical function in children. The NIH Toolbox Motor Battery (NIHTB-M) was designed to be a brief assessment of physical function, but no studies have examined its use in children with TBI. This study aims to describe the feasibility of using the NIHTB-M to assess children with TBI.

METHODS

The NIHTB-M was administered to children with TBI 2 weeks (n = 22) and/or 6 months (n = 23) following injury. This descriptive study summarizes participant performance, administration challenges, and the association between NIHTB-M scores, participant characteristics, and subjective report of physical function.

RESULTS

Of the NIHTB-M domains, deficits in endurance and balance were most prevalent. Children aged 5 to 16 years could complete the assessment per administration guidelines, except for a few cases (n = 3) where orthopedic injuries limited participation. Younger children (aged 3 to 4) had difficulty following the NIHTB-M directions. Technological issues impacted balance assessment in several cases (n = 6).

CONCLUSION

The NIHTB-M is brief to administer, generally well tolerated by school-aged children and, despite occasional technological challenges, is a feasible performance-based battery for assessment of children with TBI for clinical and research purposes. Additional investigation of psychometric properties and ceiling and floor effects is needed.

Effect of Community-Based Group Exercise Interventions on Standing Balance and Strength in Independent Living Older Adults

BACKGROUND AND PURPOSE

Many interventions to improve mobility in older adults often include exercises to address underlying impairments such as strength deficits. Task-oriented exercise interventions that focus more on walking and stepping tasks that may be encountered in the community have been considered for improving mobility in older adults. The main purpose was to examine the effect of task-oriented and impairment-based group exercise interventions on standing balance and lower extremity muscle strength.

METHODS

This is an ancillary study to a cluster-randomized clinical trial. Participants included 107 older adults. Participants were randomized by facility to 1 of 2 different interventions, or a waitlist control group. The On the Move (OTM) task-oriented intervention consisted of warm-up, timing and coordination (stepping and walking patterns), strengthening, and stretching exercises. The standard of care impairment-based exercise intervention (STD) consisted of warm-up, strength, endurance, and stretching exercises. Postural sway and balance measures were recorded before and after the 12-week interventions. An accelerometer was used to collect postural sway for 6 different standing balance conditions. A portable load cell was used to assess lower extremity muscle strength for 3 muscle groups.

RESULTS AND DISCUSSION

The OTM group had a significant reduction in sway acceleration during most of the balance conditions over the 12-week period, whereas the STD had smaller, nonsignificant reductions. Both exercise interventions had a significant reduction in sway compared with the waitlist control group in at least 1 balance condition. The OTM and STD groups had significant increases in hip abduction strength during the intervention and the STD group also had an increase in knee extension strength. The waitlist group had a significant reduction in strength in all muscle groups during the 12-week period. Strength changes in both exercise groups were significantly different from the waitlist group but not from each other.

CONCLUSION

Both exercise intervention groups had an improvement in standing balance and lower extremity strength when compared with a waitlist group that did not receive exercise. Although the exercise groups did not significantly differ from each other, the OTM exercise group showed a trend toward improvement in static standing balance conditions.

The NIH Toolbox: Overview of Development for Use with Hispanic Populations

OBJECTIVE

Hispanics/Latinos are the largest and fastest-growing minority population in the United States. To facilitate appropriate outcome assessment of this expanding population, the NIH Toolbox for Assessment of Neurological and Behavioral Function® (NIH Toolbox®) was developed with particular attention paid to the cultural and linguistic needs of English- and Spanish-speaking Hispanics/Latinos.

METHODS

A Cultural Working Group ensured that all included measures were appropriate for use with Hispanics/Latinos in both English and Spanish. In addition, a Spanish Language Working Group assessed all English-language NIH Toolbox measures for translatability.

RESULTS

Measures were translated following the Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology for instances where language interpretation could impact scores, or a modified version thereof for more simplified translations. The Spanish versions of the NIH Toolbox Cognition Battery language measures (i.e., Picture Vocabulary Test, Oral Reading Recognition Test) were developed independently of their English counterparts.

CONCLUSIONS

The Spanish-language version of the NIH Toolbox provides a much-needed set of tools that can be selected as appropriate to complement existing protocols being conducted with the growing Hispanic/Latino population in the United States.

Development of a Computerized Device for Evaluating Vestibular Function in Locomotion: A New Evaluation Tool of Vestibular Hypofunction

To evaluate vestibular function in the clinic, current assessments are applied under static conditions, such as with the subject in a sitting or supine position. Considering the complexities of daily activities, the combination of dynamic activities, dynamic visual acuity (DVA) and postural control could produce an evaluation that better reflects vestibular function in daily activities.

Objective: To develop a novel sensor-based system to investigate DVA, walking trajectory, head and trunk movements and the chest-pelvis rotation ratio during forward and backward overground walking in both healthy individuals and patients with vestibular hypofunction.

Methods: Fifteen healthy subjects and 7 patients with bilateral vestibular hypofunction (BVH) were recruited for this study. Inertial measurement units were placed on each subject's head and torso. Each subject walked forward and backward for 5 m twice with 2 Hz head yaw. Our experiment comprised 2 stages. In stage 1, we measured forward (FW), backward (BW), and medial-lateral (MLW) walking trajectories; head and trunk movements; and the chest-pelvis rotation ratio. In stage 2, we measured standing and locomotion DVA (loDVA). Using Mann–Whitney U-test, we compared the abovementioned parameters between the 2 groups.

Results: Patients exhibited an in-phase chest/pelvis reciprocal rotation ratio only in FW. The walking trajectory deviation, calculated by normalizing the summation of medial-lateral swaying with 1/2 body height (%), was significantly larger (FW mean ± standard deviation: 20.4 ± 7.1% (median (M)/interquartile range (IQR): 19.3/14.4–25.2)in healthy vs. 43.9 ± 27. 3% (M/IQR: 36.9/21.3–56.9) in patients, p = 0.020)/(BW mean ± standard deviation: 19.2 ± 11.5% (M/IQR: 13.6/10.4–25.3) in healthy vs. 29.3 ± 6.4% (M/IQR: 27.7/26.5–34.4) in patients, p = 0.026), and the walking DVA was also significantly higher (LogMAR score in the patient group [FW LogMAR: rightDVA: mean ± standard deviation:0.127 ± 0.081 (M/IQR: 0.127/0.036–0.159) in healthy vs. 0.243 ± 0.101 (M/IQR: 0.247/0.143–0.337) in patients (p = 0.013) and leftDVA: 0.136 ± 0.096 (M/IQR: 0.127/0.036–0.176) in healthy vs. 0.258 ± 0.092 (M/IQR: 0.247/0.176–0.301) in patients (p = 0.016); BW LogMAR: rightDVA: mean ± standard deviation: 0.162 ± 0.097 (M/IQR: 0.159/0.097–0.273) in healthy vs. 0.281 ± 0.130 (M/IQR: 0.273/0.176–0.418) in patients(p = 0.047) and leftDVA: 0.156 ± 0.101 (M/IQR: 0.159/0.097–0.198) in healthy vs. 0.298 ± 0.153 (M/IQR: 0.2730/0.159–0.484) in patients (p = 0.038)].

Conclusions: Our sensor-based vestibular evaluation system provided a more functionally relevant assessment for the identification of BVH patients.

Reliability and Validity of the Spanish-Language Version of the NIH Toolbox

The psychometric properties of the English-language NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox) have been examined in numerous populations. This study evaluated the reliability and validity of the Spanish-language NIH Toolbox. Participants were children aged 3 to 7 years and adults aged 18 to 85 years who took part in the NIH Toolbox norming study in Spanish. Results supported the internal consistency reliability of included measures. Test-retest reliability was strong for most tests, though it was weaker for the test of olfaction among children and the test of locomotion among adults. Spearman's correlations and general linear models showed Spanish tests were often associated with age, sex, and education. Convergent validity for the two language measures that underwent more intensive development, evaluated via Spearman's correlations with legacy measures, was strong. Results support using the Spanish-language NIH Toolbox to measure neurological and behavioral functioning among Spanish-speaking individuals in the United States.

Psychometric properties of instrumented postural sway measures recorded in community settings in independent living older adults

Background

In the last few decades, research related to balance in older adults has been conducted in lab-based settings. The lack of portability and high cost that is associated with the current gold standard methods to quantify body balance limits their application to community settings such as independent living facilities. The purpose of the study was to examine the relative and absolute reliability and the convergent validity of static standing balance performance using an accelerometer device.

Methods

A total of 131 participants (85% female, mean age 80 ± 8 years) were included for the validity aim, and a subsample of 38 participants were enrolled in the reliability testing (89% female, mean age 76 ± 7 years). The root-mean-square (RMS) and normalized path length (NPL) for sway in antero-posterior (AP) and medio-lateral (ML) directions were calculated for different standing balance conditions. Test-retest reliability was assessed over two testing visits occurring 1 week apart using the intraclass correlation coefficient (ICC) for relative reliability, and the minimal detectable change (MDC) was calculated for the absolute reliability. Spearman’s rank correlation coefficient was used to test convergent validity at baseline between balance measurements and related mobility measures.

Results

Reliability of balance performance using accelerometers was good to excellent with ICC values ranging from 0.41 to 0.83 for RMS sway and from 0.49 to 0.82 for NPL sway. However, the ICC during semi-tandem stance in A-P direction was 0.35, indicating poor reliability. The MDC of the sway measurements ranged from 2.4 to 9.4 for the RMS and 5.2 to 13.8 for the NPL. Balance measurements were correlated with mobility measurements.

Conclusions

Using a portable accelerometer to quantify static standing postural control provides reliable measurements in community settings.

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.

Rehabilitation to improve gaze and postural stability in people with multiple sclerosis: study protocol for a prospective randomized clinical trial

BACKGROUND

The use of vestibular rehabilitation principles in the management of gaze and postural stability impairments in people with multiple sclerosis (PwMS) has shown promise in pilot work completed in our lab and in a recently published randomized clinical trial (RCT). However, further work is needed to fully quantify the gaze and postural impairments present in people with multiple sclerosis and how they respond to rehabilitation.

METHODS/DESIGN

The study is a single blind RCT designed to examine the benefit of a gaze and postural stability (GPS) intervention program compared to a standard of care (SOC) rehabilitation program in dizzy and balance impaired PwMS. Outcomes will be collected across the domains of body structure and function, activity, and participation as classified by the World Health Organization International Classification of Functioning, Disability, and Health (ICF). Our primary outcomes are the Dizziness Handicap Inventory (DHI) and the Functional Gait Assessment (FGA). Secondary outcomes include other measures of gaze and postural stability, fatigue, and functional mobility. Participants who are interested and eligible for enrollment will be consented prior to completing a baseline assessment. Following the baseline assessment each participant will be randomized to either the GPS or SOC intervention group and will complete a 6 week treatment period. During the treatment period, both groups will participate in guided exercise 3x/week. Following the treatment period participants will be asked to return for a post-treatment evaluation and again for a follow-up assessment 1 month later. We anticipate enrolling 50 participants.

DISCUSSION

This study will be an innovative RCT that will utilize gaze and postural stability metrics to assess the efficacy of vestibular rehabilitation in PwMS. It will build on previous work by examining measures across the ICF and improve the current evidence base for treating PwMS.

TRIAL REGISTRATION

ClinicalTrials.gov, May 29th 2018, NCT03521557 .

Inertial wearables as pragmatic tools in dementia

Dementia is a critically important issue due to its wide impact on health services as well as its personal and societal costs. Limitations exist for current dementia protocols, and there are calls to introduce modern technology that facilitates the addition of digital biomarkers to routine clinical practice. Wearable technology (wearables) are nearly ubiquitous in everyday life, gathering discrete and continuous digital data on habitual activities, but their utility in modern medicine remains low. Due to advances in data analytics, wearables are now commonly discussed as pragmatic tools to aid the diagnosis and treatment of a range of neurological disorders. Inertial sensor-based wearables are one such technology; they offer a low-cost approach to quantify routine movements that are fundamental to normal activities of daily living, most notably postural control and gait. Here, we provide a narrative review of how wearables are providing useful postural control and gait data to facilitate the capture of digital markers to aid dementia research. We outline the history of wearables, from their humble beginnings to their current use beyond the clinic, and explore their integration into modern systems, as well as the ongoing standardisation and regulatory efforts to integrate their use in clinical trials.

Evaluation of the Military Functional Assessment Program for Return-to-Duty Decision Making: A Longitudinal Study

Following concussion, return-to-duty decisions are made by medical providers and leaders using informal assessment, review of symptom resolution, and clinical assessments. In an effort to provide military-specific tasks for use in the decision making regarding return-to-duty, a battery developed from the set of basic soldier skills, the Military Functional Assessment Program (MFAP), was evaluated for construct validity using clinical assessment outcomes as well as the relationships between MFAP performance and indicators of long-term performance and satisfaction. A total of 48 participants were enrolled in the study providing baseline and post-treatment clinical assessment, and MFAP performance data. Twenty participants provided follow-up data at 6-month post-MFAP. Correlational analyses suggest significant relationships between MFAP performance ratings and clinical measures of vestibular and cognitive functions and psychological well-being. These findings are consistent with those from previous research on construct validity of the MFAP tasks. Performance on one MFAP task related to perceptions of performance and overall MFAP ratings related to satisfaction reported at 6 months. These findings provide preliminary, however limited, support for these tasks being indicative of the motivation and mental state of the program participant.

Instrumented Test of Sensory Integration for Balance: A Validation Study

BACKGROUND AND PURPOSE

Abnormal postural sway is associated with an increase in risk of falls but is difficult for clinicians to accurately quantify without access to laboratory equipment. Instrumenting clinical outcome measures using body-worn movement monitors is a low-cost alternative. This is the first study to compare the modified Clinical Test of Sensory Integration for Balance (i-mCTSIB) to the laboratory test of the Sensory Organization Test (SOT) with dynamic posturography in a group of participants with Parkinson's disease (PD) and subtle balance limitations. The purpose of this study was to (1) determine the concurrent validity of the i-mCTSIB with the SOT (6 and 4 conditions) and (2) compare the i-mCTSIB and the SOT to differentiate between individuals with and without recent falls within the previous 6 months.

METHODS

This cross-sectional study examined 26 participants with idiopathic PD who had a Motor Unified Parkinson's Disease Rating Scale score of 32.7 (13.5) out of 108.

RESULTS

The composite and conditions 1 and 4 of the i-mCTSIB and SOT scores were significantly correlated: composite scores r = -0.64 (P ≤ .001), C1 r = -0.43 (P = .03), C3 r = -0.60 (P ≤ .01), and C4 r = -0.54 (P ≤ .001). A significant difference was observed in mean i-mCTSIB composite scores between fallers and nonfallers (P = .04). In contrast, the SOT composite was not significantly different between fallers and nonfallers (P = 0.31).

DISCUSSION

The results suggest that the i-mCTSIB may be a valid and clinically meaningful measure of sensory organization in persons with PD, even those with mild postural instability as measured by the median Hoehn and Yahr score (2.0). Future research should evaluate predictive validity of the i-mCTSIB for prospective falls.

CONCLUSION

The instrumented mCTSIB with portable, body-worn movement allows clinicians to quantify abnormal postural sway without the ceiling effects of clinical balance testing or the expense and importability of force plate technology in the SOT. Instrumenting mCTSIB may also distinguish between fallers and nonfallers.

The Effect of Cognitive Resource Competition Due to Dual-Tasking on the Irregularity and Control of Postural Movement Components

Postural control research suggests a non-linear, n-shaped relationship between dual-tasking and postural stability. Nevertheless, the extent of this relationship remains unclear. Since kinematic principal component analysis has offered novel approaches to study the control of movement components (PM) and n-shapes have been found in measures of sway irregularity, we hypothesized (H1) that the irregularity of PMs and their respective control, and the control tightness will display the n-shape. Furthermore, according to the minimal intervention principle (H2) different PMs should be affected differently. Finally, (H3) we expected stronger dual-tasking effects in the older population, due to limited cognitive resources. We measured the kinematics of forty-one healthy volunteers (23 aged 26 ± 3; 18 aged 59 ± 4) performing 80 s tandem stances in five conditions (single-task and auditory n-back task; n = 1–4), and computed sample entropies on PM time-series and two novel measures of control tightness. In the PM most critical for stability, the control tightness decreased steadily, and in contrast to H3, decreased further for the younger group. Nevertheless, we found n-shapes in most variables with differing magnitudes, supporting H1 and H2. These results suggest that the control tightness might deteriorate steadily with increased cognitive load in critical movements despite the otherwise eminent n-shaped relationship.

Visual dependence affects postural sway responses to continuous visual field motion in individuals with cerebral palsy

The current study aimed to explore the impact of visual dependence on sensorimotor coupling of postural sway and visual motion in adults and teens with spastic cerebral palsy (CP). We hypothesized that individuals with CP would exhibit greater magnitudes of sway than healthy individuals, and the presence of visual dependence (VD) would produce instability in the direction of visual motion. Participants stood in a virtual environment in which the visual scene remained static or continuously rotated 30 degree/second in pitch-up or pitch-down. Increased center of pressure and center of mass responses were observed in the direction of visual scene motion in those with CP. Those with VD exhibited reduced frequency responses in anterior-posterior direction than those who were visually independent. VD suggests deficient sensorimotor integration that could contribute to postural instability and reduced motor function. Individuals with CP who are visually dependent may benefit from more sensory focused rehabilitation strategies.

ABBREVIATIONS

AP, anterior-posterior; CP, cerebral palsy; COM, center of mass; COP, center of pressure; MDF, median frequency; ML, mediolateral; PD, pitch down (nose down) rotation; PU, pitch up (nose up) rotation; RFT, rod and frame test; RMS, root mean square; SLP, slope of the fitted line; TD, typical development; VD, visual dependence; VI, visual independence; VOR, vestibulo-ocular reflex; VPI, visual perceptual impairment.

Reliability of Postural Sway Measures of Standing Balance Tasks

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.

Predictive Factors for Vestibular Loss in Children With Hearing Loss

PURPOSE

The aim of this study was to determine if there are factors that can predict whether a child with hearing loss will also have vestibular loss.

METHOD

A retrospective chart review was completed on 186 children with hearing loss seen at Boys Town National Research Hospital for vestibular testing from 1999 to 2015 through neurosensory genetics clinic or cochlear implant candidacy. Each child's medical chart was reviewed to obtain the following data: vestibular loss severity (classified as normal, bilateral, or mild to moderate), degree of hearing loss (bilateral pure-tone average [PTA]), imaging abnormalities (classified as "normal" or "abnormal"), parental concerns for gross motor delay (classified as "yes, there is concern" or "no, there is not a concern"), parent report of age when their child sat (months) and walked independently (months), comorbidities (classified as "yes" if there were 1 or more comorbidities or "no" if there were no comorbidities), and score on the Developmental Profile-3.

RESULTS

Children were grouped according to vestibular loss severity; 115 children had normal vestibular function, 31 had bilateral vestibular loss, and 40 had mild-to-moderate vestibular loss. As severity of vestibular loss increased, children (a) sat and walked later, (b) scored more poorly on the Developmental Profile-3 physical subscale, (c) had more severe hearing loss, (d) had parents who more frequently reported concern for gross motor delay, and (e) were more likely to have other comorbidities. Of these factors, age-to-sit, age-to-walk, PTA, and parental concerns for gross motor developmental delay had the greatest ability to differentiate children with vestibular loss from children with normal vestibular function. For age-to-sit, using a cutoff value of 7.25 months yielded a sensitivity of 62% and a specificity of 81%. For age-to-walk, a cutoff value of 14.5 months yielded a sensitivity of 78% and a specificity of 77%. For PTA for the neurosensory genetics group, a cutoff value of 40 dB yielded a sensitivity of 80% and a specificity of 55%; however, a cutoff value of 66 dB yielded a sensitivity of 33% and an improved specificity of 91%.

CONCLUSIONS

A referral for vestibular evaluation should be considered for children whose hearing loss is greater than 66 dB and particularly those who sit later than 7.25 months or walk later than 14.5 months or whose parents report concerns for gross motor development. Collectively, these factors appear to be more sensitive for identifying children with bilateral vestibular loss compared with children with mild-to-moderate vestibular loss. Because of the benefit of physical therapy, children identified with vestibular loss should then be referred to physical therapy for further evaluation and treatment.

Feasibility of the clinical dynamic visual acuity test in typically developing preschoolers

OBJECTIVES

To determine the feasibility of the dynamic visual acuity test (DVA) in children who are preschoolers.

METHODS

Thirty-three preschoolers [3 years old (n = 11), 4 years old (n = 6), 5 years old (n = 8), and 6 years old (n = 8)], performed a static visual acuity test (SVA), a passive horizontal DVA (hDVA) at 1 and 2 Hz, and a DVA on treadmill at three age-specific walking speeds (slow/medium/high). The DVA scores, the difference between SVA and hDVA, were used to determine false positive results.

RESULTS

The SVA was performed by 31/33 children, the hDVA and DVA on treadmill at slow and medium speed by 27/33 and the DVA on treadmill at high speed by 25/33. Except for one 5 years old, all drop-outs were 3 years old. The hDVA at 2 Hz was administered in only six children because of difficulties with focusing on reading the symbols at this frequency. False positive results for the hDVA at 1 Hz were found in 3/27 children, all 3 years old, and 2/6 for the hDVA at 2 Hz.

CONCLUSIONS

The DVA on treadmill seems useful for preschoolers from age 5, but this should be further investigated in children with underlying pathologies.

Concussion Assessment With Smartglasses: Validation Study of Balance Measurement Toward a Lightweight, Multimodal, Field-Ready Platform

BACKGROUND

Lightweight and portable devices that objectively measure concussion-related impairments could improve injury detection and critical decision-making in contact sports and the military, where brain injuries commonly occur but remain underreported. Current standard assessments often rely heavily on subjective methods such as symptom self-reporting. Head-mounted wearables, such as smartglasses, provide an emerging platform for consideration that could deliver the range of assessments necessary to develop a rapid and objective screen for brain injury. Standing balance assessment, one parameter that may inform a concussion diagnosis, could theoretically be performed quantitatively using current off-the-shelf smartglasses with an internal accelerometer. However, the validity of balance measurement using smartglasses has not been investigated.

OBJECTIVE

This study aimed to perform preliminary validation of a smartglasses-based balance accelerometer measure (BAM) compared with the well-described and characterized waist-based BAM.

METHODS

Forty-two healthy individuals (26 male, 16 female; mean age 23.8 [SD 5.2] years) participated in the study. Following the BAM protocol, each subject performed 2 trials of 6 balance stances while accelerometer and gyroscope data were recorded from smartglasses (Glass Explorer Edition). Test-retest reliability and correlation were determined relative to waist-based BAM as used in the National Institutes of Health's Standing Balance Toolbox.

RESULTS

Balance measurements obtained using a head-mounted wearable were highly correlated with those obtained through a waist-mounted accelerometer (Spearman rho, ρ=.85). Test-retest reliability was high (intraclass correlation coefficient, ICC2,1=0.85, 95% CI 0.81-0.88) and in good agreement with waist balance measurements (ICC2,1=0.84, 95% CI 0.80-0.88). Considering the normalized path length magnitude across all 3 axes improved interdevice correlation (ρ=.90) while maintaining test-retest reliability (ICC2,1=0.87, 95% CI 0.83-0.90). All subjects successfully completed the study, demonstrating the feasibility of using a head-mounted wearable to assess balance in a healthy population.

CONCLUSIONS

Balance measurements derived from the smartglasses-based accelerometer were consistent with those obtained using a waist-mounted accelerometer. Additional research is necessary to determine to what extent smartglasses-based accelerometry measures can detect balance dysfunction associated with concussion. However, given the potential for smartglasses to perform additional concussion-related assessments in an integrated, wearable platform, continued development and validation of a smartglasses-based balance assessment is warranted. This approach could lead to a wearable platform for real-time assessment of concussion-related impairments that could be further augmented with telemedicine capabilities to integrate professional clinical guidance. Smartglasses may be superior to fully immersive virtual reality headsets for this application, given their lighter weight and reduced likelihood of potential safety concerns.

Standing balance and strength measurements in older adults living in residential care communities

Research on balance and mobility in older adults has been conducted primarily in lab-based settings in individuals who live in the community. Although they are at greater risk of falls, residents of long-term care facilities, specifically residential care communities (RCCs), have been investigated much less frequently. We sought to determine the feasibility of using portable technology-based measures of balance and muscle strength (i.e., an accelerometer and a load cell) that can be used in any RCC facility. Twenty-nine subjects (age 87 ± 6 years) living in RCCs participated. An accelerometer placed on the back of the subjects measured body sway during different standing conditions. Sway in antero-posterior and mediolateral directions was calculated. Lower extremity strength was measured with a portable load cell and the within-visit reliability was determined. Assessments of grip strength, gait speed, frailty, and comorbidity were also examined. A significant increase in postural sway in both the AP and ML directions occurred as the balance conditions became more difficult due to alteration of sensory feedback (p < 0.001) or reducing the base of support (p < 0.001). There was an association between increased sway and increased frailty, more comorbidities and slower gait speed. All strength measurements were highly reliable (ICC = 0.93-0.99). An increase in lower extremity strength was associated with increased grip strength and gait speed. The portable instruments provide inexpensive ways for measuring balance and strength in the understudied RCC population, but additional studies are needed to examine their relationship with functional outcomes.

Recruitment and baseline characteristics of the Community of Voices choir study to promote the health and well-being of diverse older adults

Objective

To describe the recruitment and baseline results of the Community of Voices study that aims to examine the effect of a community choir intervention on the health and well-being of older adults from diverse racial/ethnic and socioeconomic backgrounds.

Method

Using community-based participatory research methods, we recruited adults age 60 and over from 12 Administration on Aging-supported senior centers in San Francisco into a 2-arm cluster-randomized controlled trial of the community choir intervention. Multiple outreach methods were used. We tracked outreach, screening, and recruitment metrics and collected demographics and baseline outcomes via community-based, interviewer-administered surveys and performance measures of cognition, physical function, and psychosocial variables.

Results

The study contacted 819 individuals, screened 636, and enrolled 390 diverse older adults over a 42-month, phased recruitment period. The mean age was 71.2 (SD = 7.3), and the majority were women. Two-thirds of the sample are non-white, and 20% of participants reported having financial hardship.

Discussion

Outreach and recruitment methods used in the Community of Voices trial facilitated enrollment of a large proportion of minority and lower-SES older adults in the final sample. Similar recruitment approaches could serve as a model for recruiting diverse racial/ethnic and socioeconomic older adults into research.

Validation of the NIH Toolbox in Individuals with Neurologic Disorders

OBJECTIVE

Individuals with spinal cord injury (SCI), traumatic brain injury (TBI), and stroke experience a variety of neurologically related deficits across multiple domains of function. The NIH Toolbox for the Assessment of Neurological and Behavioral Function (NIHTB) examines motor, sensation, cognition, and emotional functioning. The purpose of this paper is to establish the validity of the NIHTB in individuals with neurologic conditions.

METHODS

Community-dwelling individuals with SCI (n = 209), TBI (n = 184), or stroke (n = 211) completed the NIHTB. Relative risks for impaired performance were examined relative to a matched control groups.

RESULTS

The largest group differences were observed on the Motor domain and for the Fluid Cognition measures. All groups were at increased risk for motor impairment relative to normative standards and matched controls. Fluid cognitive abilities varied across groups such that individuals with stroke and TBI performed more poorly than individuals with SCI; increased relative risks for impaired fluid cognition were seen for individuals in the stroke and TBI groups, but not for those in the SCI group. All three neurologic groups performed normally on most measures in the Sensation Battery, although TBI participants evidenced increased risk for impaired odor identification and the stroke group showed more vision difficulties. On the Emotion Battery, participants in all three groups showed comparably poor psychological well-being, social satisfaction, and self-efficacy, whereas the TBI group also evidenced slightly increased negative affect.

CONCLUSIONS

Data provide support for the validity of the NIHTB in individuals with neurologic conditions.

Age-related differences in Fukuda stepping and Babinski-Weil tests, within-day variability and test-retest reliability

BACKGROUND

The Fukuda stepping and Babinski-Weil tests are associated with unperceived body rotation and linear displacements in young adults, but performance in older adults on these two tests has yet to be determined.

AIM

The main purpose was to compare the performance and reliability of the Fukuda stepping and Babinski-Weil tests in young and older adults.

METHODS

Fifty older and 50 young adults executed three trials of each test on day 1 (test) and day 2 (retest). Lateral and longitudinal displacements and body rotation relative to the starting position were measured. Means and standard deviations (SD) were compared between the two groups with Mann-Whitney tests. Test-retest reliability was assessed with intra-class correlation coefficients (ICC). Foot preference was determined from the score on the Waterloo Footedness Questionnaire and correlated with test scores.

RESULTS

Lateral and longitudinal displacements were significantly larger in older than young participants on the Fukuda stepping test (p < .01) and significantly smaller on the Babinski-Weil test (p < .001). Older participants displayed a significantly smaller SD on the three Babinski-Weil test trials (p < .001). Displacement and rotation measures ICC ranged between 0.25 and 0.77 in older and between 0.58 and 0.80 in young participants. Foot preference correlated with rotation on the Fukuda stepping test in young (p < .05), but not in older participants (p > .05).

DISCUSSION AND CONCLUSION

Linear displacements, but not body rotation, were different between older and young adults. There was no clear age-related differences in test-retest reliability, but the moderate reliability indicates that performance can vary from day to day in both age groups.

A systematic review and meta-analysis of outcome measures to assess postural control in older adults who undertake exergaming

Exergaming has been shown to be an effective tool to improve postural control (PC) in older community-dwelling individuals. The outcome measures (OMs) used to assess PC are varied and this could limit the estimation of the effectiveness of the intervention. This systematic review and meta-analysis aims to explore the OMs currently used to assess PC in exergaming interventions, for healthy elderly individuals aged over 60 years. The literature search was conducted across five databases (CINAHL, EMBASE, PubMed, ISI, SPORTdiscus and Science Direct) using a range of search terms and combinations relating to exergaming, balance, exercise, falls and elderly. Quality assessment was conducted using the PEDro Scale and a custom-made quality assessment tool. Eleven trials were included in the meta-analysis, with a mean (SD) PEDro score of 5.36 (1.57). Primary and secondary OMs showed small effects in favour of alternative training modes, although these effects were statistically insignificant for all primary OMs. Tertiary OMs could not be included in the meta-analysis due to varying output parameters from different instruments. Heterogeneity remained high across trials and no studies performed long-term follow-up. Exergaming is a potential alternative to PC training, although still in its infancy. Strong and well-designed RCTs are needed, targeting specific populations aged over 60 years. Variability in instrumented OMs prevents generalisation of results. Technological improvements may provide data not currently available from clinical and laboratory-based methods, and may allow PC to be assessed more realistically and specifically in relation to a population's activities of daily living, though this remains a new area of research.

Vestibular, Visual Acuity, and Balance Outcomes in Children With Cochlear Implants: A Preliminary Report

OBJECTIVES

There is a high incidence of vestibular loss in children with cochlear implants (CCI). However, the relationship between vestibular loss and various outcomes is unknown in children. The objectives of this study are to (1) determine whether age-related changes in peripheral vestibular tests occur; (2) quantify peripheral vestibular function in children with normal hearing and CCI; and (3) determine whether amount of vestibular loss predicts visual acuity and balance performance.

DESIGN

Eleven CCI and 12 children with normal hearing completed the following tests of vestibular function: ocular and cervical vestibular-evoked myogenic potential to assess utricle and saccule function and the video head impulse test to assess semicircular canal function. The relationship between amount of vestibular loss and the following balance and visual acuity outcomes was assessed: dynamic gait index, single-leg stance, the sensory organization test, and tests of visual acuity, including dynamic visual acuity and the gaze stabilization test.

RESULTS

(1) There were no significant age-related changes in peripheral vestibular testing with the exception of the n23 cervical vestibular-evoked myogenic potential latency, which was moderately correlated with age. (2) CCI had significantly higher rates of vestibular loss for each test of canal and otolith function. (3) Amount of vestibular loss predicted performance on single-leg stance, the dynamic gait index, some conditions of the sensory organization test, and the dynamic visual acuity test. Age was also a contributing factor for predicting the performance of almost all outcomes.

CONCLUSIONS

Preliminarily, children with vestibular loss do not recover naturally to levels of their healthy peers, particularly with activities that utilize vestibular input; they have poorer visual acuity and balance function.

Validity of visual perceptive computing for static posturography in patients with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) patients frequently have postural control impairment but quantitative posturography is difficult to perform in clinical care. Recent technology facilitates new posturography approaches.

OBJECTIVE

To evaluate construct validity of visual perceptive computing (VPC) for static posturography to study postural control in MS patients.

METHODS

A total of 90 MS patients and 59 healthy controls (HCs) performed three stance tests: open, closed and tandem stance. Static posturography was performed using a VPC system with Microsoft Kinect. Clinical assessments included Expanded Disability Status Scale (EDSS), Timed-25-Foot-Walk, Short-Maximum-Speed-Walk and 12-item MS Walking Scale (MSWS-12) questionnaire. Reliability was assessed with intra-class correlation coefficients at retest.

RESULTS

As a group, MS patients performed worse than HCs in all tests. The closed stance test showed best applicability and reliability. With closed eyes, in 36.7% of patients, the three-dimensional mean angular sway velocity (MSV-3D) was above HCs' 95th percentile. Higher MSV-3D was associated with decreased walking speed (p < 0.001); worse clinical scores, mainly attributable to the cerebellar functional system score (p < 0.001); and reflected in self-reported walking disability (MSWS-12, p < 0.001).

CONCLUSION

Postural control can be reliably assessed by VPC-based static posturography in patients with MS. Abnormal postural control seems to predominantly reflect involvement of cerebellar circuits with impact on gait and walking disability.

Time-dependent changes in postural control in early Parkinson's disease: what are we missing?

Impaired postural control (PC) is an important feature of Parkinson's disease (PD), but optimal testing protocols are yet to be established. Accelerometer-based monitors provide objective measures of PC. We characterised time-dependent changes in PC in people with PD and controls during standing, and identified outcomes most sensitive to pathology. Thirty-one controls and 26 PD patients were recruited: PC was measured with an accelerometer on the lower back for 2 minutes (mins). Preliminary analysis (autocorrelation) that showed 2 seconds (s) was the shortest duration sensitive to changes in the signal; time series analysis of a range of PC outcomes was undertaken using consecutive 2-s windows over the test. Piecewise linear regression was used to fit the time series data during the first 30 s and the subsequent 90 s of the trial. PC outcomes changed over the 2 mins, with the greatest change observed during the first 30 s after which PC stabilised. Changes in PC were reduced in PD compared to controls, and Jerk was found to be discriminative of pathology. Previous studies focusing on average performance over the duration of a test may miss time-dependent differences. Evaluation of time-dependent change may provide useful insights into PC in PD and effectiveness of intervention.

Instrumented assessment of test battery for physical capability using an accelerometer: a feasibility study

Recent work has identified subdomains (tests) of physical capability that are recommended for assessment of the healthy ageing phenotype (HAP). These include: postural control, locomotion, endurance, repeated sit-to-stand-to-sit and TUG. Current assessment methods lack sensitivity and are error prone due to their lack of consistency and heterogeneity of reported outcomes; instrumentation with body worn monitors provides a method to address these potential weaknesses. This work proposes the use of a single tri-axial accelerometer-based device with appropriate algorithms (referred to here as a body worn monitor, BWM) for the purposes of instrumented testing during physicality capability assessment. In this pilot study we present 14 BWM-based outcomes across the subdomains which include magnitude, frequency and spatio-temporal characteristics. Where possible, we compared BWM outcomes with manually recorded values and found no significant differences between locomotion and TUG tasks (p ≥ 0.319). Significant differences were found for the total distance walked during endurance (p = 0.037) and times for repeated sit-to-stand-to-sit transitions (p < 0.000). We identified reasons for differences and make recommendations for future testing. We were also able to quantify additional characteristics of postural control and gait which could be sensitive outcomes for future HAP assessment. Our findings demonstrate the feasibility of this method to enhance measurement of physical capacity. The methodology can also be applied to a wide variety of accelerometer-based monitors and is applicable to a range of intervention-based studies or pathological assessment.

iCap: Instrumented assessment of physical capability

•

Instrumented testing of five physical capability tasks with a single accelerometer.

•

Evaluated on a large cohort of older adults.

•

iCap provides robust quantitative data about physical capability.

•

iCap captures gait and postural control data known as sensitive to ageing/pathology.

•

Methodology may have practical utility in a wide range of surveys and studies.

Objectives

The aims of this study were to (i) investigate instrumented physical capability (iCap) as a valid method during a large study and (ii) determine whether iCap can provide important additional features of postural control and gait to categorise cohorts not previously possible with manual recordings.

Study design

Cross-sectional analysis involving instrumented testing on 74 adults who were recruited as part of a pilot intervention study; LiveWell. Participants wore a single accelerometer-based monitor (lower back) during standardised physical capability tests so that outcomes could be compared directly with manual recordings (stopwatch and measurement tape) made concurrently.

Main outcome measures

Time, distance, postural control and gait characteristics.

Results

Agreement between manual and iCap ranged from moderate to excellent (0.649–0.983) with mean differences between methods low and deemed acceptable. Additionally, iCap successfully quantified (i) postural control characteristics which showed sensitivity to distinguish between 5 variations of the standing balance test and (ii) 14 gait characteristics known to be sensitive to age/pathology.

Conclusions

Our findings show that iCap can provide robust quantitative data about physical capability during standardised tests while also providing sensitive (age/pathology) postural control and gait characteristics not previously quantifiable with manual recordings. The methodology which we propose may have practical utility in a wide range of clinical and public health surveys and studies, including intervention studies, where assessment could be undertaken within diverse settings. This will need to be tested in further validation studies in a wider range of settings.

Instrumenting gait with an accelerometer: a system and algorithm examination

Gait is an important clinical assessment tool since changes in gait may reflect changes in general health. Measurement of gait is a complex process which has been restricted to the laboratory until relatively recently. The application of an inexpensive body worn sensor with appropriate gait algorithms (BWM) is an attractive alternative and offers the potential to assess gait in any setting. In this study we investigated the use of a low-cost BWM, compared to laboratory reference using a robust testing protocol in both younger and older adults. We observed that the BWM is a valid tool for estimating total step count and mean spatio-temporal gait characteristics however agreement for variability and asymmetry results was poor. We conducted a detailed investigation to explain the poor agreement between systems and determined it was due to inherent differences between the systems rather than inability of the sensor to measure the gait characteristics. The results highlight caution in the choice of reference system for validation studies. The BWM used in this study has the potential to gather longitudinal (real-world) spatio-temporal gait data that could be readily used in large lifestyle-based intervention studies, but further refinement of the algorithm(s) is required.

Canal plane dynamic visual acuity in superior canal dehiscence

OBJECTIVE

1) To characterize normal, horizontal active dynamic visual acuity (DVA) and passive canal plane head thrust DVA (htDVA) across ages to establish appropriate control data and 2) to determine whether horizontal active DVA and passive canal plane htDVA are significantly different in individuals with superior canal dehiscence syndrome (SCDS) before and after surgical repair in the acute (within 10 d) and nonacute stage (>6 wk).

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center

PATIENTS

Patients diagnosed with SCDS (n = 32) and healthy control subjects (n = 51).

INTERVENTIONS

Surgical canal plugging on a subset of patients.

MAIN OUTCOME MEASURES

Static visual acuity (SVA), active horizontal DVA, and canal plane htDVA.

RESULTS

Visual acuity (SVA, active DVA, and htDVA) declines with age. In SCDS, SVA and active DVA are not significantly affected in individuals after surgical canal plugging; however, htDVA in the plane of the affected canal is significantly worse after canal plugging.

CONCLUSION

Age-based normative data are necessary for DVA testing. In SCDS, htDVA in the plane of the affected canal is normal before surgery but permanently reduced afterward.

Integrated testing of standing balance and cognition: test-retest reliability and construct validity

Balance and cognitive impairments which are common with aging often coexist, are prognostic of future adverse health events, including fall injuries. Consequently, dual-task assessment programs that simultaneously address both stability and cognition are important to consider in rehabilitation and benefit healthy aging. The objective of this study was to establish test-retest reliability and construct validity of a dual-task computer game-based platform (TGP) that integrates head tracking and cognitive tasks with balance activities. Thirty healthy, community-dwelling individuals median age 64 (range 60-67) were recruited from a certified Medical Fitness Facility. Participants performed a series of computerized head tracking and cognitive game tasks while standing on fixed and sponge surfaces. Testing was conducted on two occasions, one week apart. Moderate to high test retest reliability (ICC values of 0.55-0.75) was observed for all outcome measures representing balance, gaze performance, cognition, and dual-task performance. A significant increase in center of foot pressure (COP) excursion was observed during both head tracking and cognitive dual-task conditions. The results demonstrate the system's ability to reliably detect changes related to specific and integrated aspects of balance, gaze, and cognitive performance.

Normative Scores for the NIH Toolbox Dynamic Visual Acuity Test from 3 to 85 Years

As part of the National Institutes of Health Toolbox initiative, a computerized test of dynamic visual acuity (cDVA) was developed and validated as an easy-to-administer, cost- and time-efficient test of vestibular and visual function. To establish normative reference values, 3,992 individuals, aged 3–85 years, without vestibular pathology underwent cDVA testing at multiple clinical research testing facilities across the United States. Test scores were stratified by sociodemographic characteristics. cDVA was worse in males (p < 0.001) and those subjects 50 years or older, while there was no difference in dynamic visual acuity across age groups binned from 3 to 49 years. Furthermore, we used these normative cDVA data as a criterion reference to compare both the long (validated) and short versions of the test. Both versions can distinguish between those with and without vestibular pathology (p = 0.0002 long; p = 0.0025 short). The intraclass correlation coefficient between long- and short-cDVA tests was 0.86.