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Wearable sensors are increasingly popular in concussion research because of their objective quantification of subtle balance deficits. However, normative data and minimal detectable change (MDC) values are necessary to serve as references for diagnostic use and tracking longitudinal recovery. To identify normative and MDC values for instrumented static- and reactive-balance tests, an instrumented static mediolateral (ML) root mean square (RMS) sway standing balance assessment and the instrumented, modified push and release (I-mP&R), respectively. Cross-sectional study. Clinical setting. Normative static ML RMS sway and I-mP&R data were collected on 377 (n = 184 female) healthy National Collegiate Athletic Association Division I athletes at the beginning of their competitive seasons. Test-retest data were collected in 36 healthy control athletes based on standard recovery timelines after concussion. Descriptive statistics, intraclass correlation coefficients (ICCs), and MDC values were calculated for primary outcomes of ML RMS sway in a static double-limb stance on firm ground and a foam block, and time to stability and latency from the I-mP&R in single- and dual-task conditions. Normative outcomes across static ML RMS sway and I-mP&R were sensitive to sex and type of footwear. Mediolateral RMS sway demonstrated moderate reliability in the firm condition (ICC = 0.73; MDC = 2.7 cm/s2) but poor reliability in the foam condition (ICC = 0.43; MDC = 11.1 cm/s2). Single- and dual-task times to stability from the I-mP&R exhibited good reliability (ICC = 0.84 and 0.80, respectively; MDC = 0.25 and 0.29 seconds, respectively). Latency from the I-mP&R had poor to moderate reliability (ICC = 0.38 and 0.55; MDC = 107 and 105 milliseconds). Sex-matched references should be used for instrumented static- and reactive-balance assessments. Footwear may explain variability in static ML RMS sway and time to stability of the I-mP&R. Moderate-to-good reliability suggests time to stability from the I-mP&R and ML RMS static sway on firm ground can be used for longitudinal assessments. [ABSTRACT FROM AUTHOR]

Context: Traditional assessments of reactive balance require sophisticated instrumentation to ensure objective, highly repeatable paradigms. This instrumentation is clinically impractical. The Push and Release test (P&R) is a well-validated clinical test that examines reactive balance, and the application of wearable inertial measurement units (IMU) enables sensitive and objective assessment of this clinically feasible test. The P&R relies on administrator experience and may be susceptible to interadministration reliability concerns. The purpose of this study was to evaluate the interadministrator reliability of objective outcomes from an instrumented, modified version of the P&R test. Design: Crossover interadministrator design. Methods: Twenty healthy adults (20–35 y) completed the P&R in 4 directions with 2 different administrators. Measures quantified using IMUs included step latency, step length, and time to stability. Lean angle (LA) at release was used as a measure of administration consistency. The intraclass correlation coefficient (ICC) estimate was used to assess interadministrator reliability in each direction. To determine consistency of LA within and across administrators, we calculated the SDs for each rater by direction and the interadministrator reliability of LA using ICC. Results: Across individual directions, the ICC for agreement between raters ranged from .16 to .39 for step latency, from .52 to .62 for time to stability, and from .48 to .84 for step length. Summary metrics across all 4 directions produced higher ICC values. There was poor to moderate consistency in administration based on LA, but LA did not significantly affect any of the outcomes. Conclusion: The modified P&R yields moderate interadministrator reliability and high validity. Summary metrics over all 4 directions (the maximum step latency, the median time to stability, and the median step length) are likely more reliable than direction-specific scores. Variations in body size should also be considered when comparing populations. [ABSTRACT FROM AUTHOR]

Current clinical concussion evaluations assess balance deficits using static or dynamic balance tasks while largely ignoring reactive balance. Including a reactive balance assessment might provide a more comprehensive concussion evaluation. To identify redundancy in current clinical baseline assessments of concussion and determine whether reactive balance adds unique information to these evaluations. Cross-sectional study. Clinical assessment. A total of 279 healthy National Collegiate Athletic Association Division I athletes. Two cohorts of data were collected at the beginning of the athletic season. For cohort 1 (n = 191), the Immediate Post-Concussion Assessment and Cognitive Tool, instrumented modified push and release (I-mP&R), and Balance Error Scoring System (BESS) were administered. For cohort 2 (n = 88), the I-mP&R, BESS, timed tandem gait, walking with eyes closed, and clinical reaction time were administered. The strengths of the relationships between the Immediate Post-Concussion Assessment and Cognitive Tool cognitive indices, mP&R clinical score, instrumented measures (BESS sway; I-mP&R time to stability, latency, and step length), BESS score, timed tandem gait, walking time to completion, and clinical reaction time were characterized. The strongest interinstrument correlation value was between single-task time to stability from the I-mP&R and clinical reaction time but was considered weak (r = 0.35, P =.001). The mP&R and I-mP&R clinical scores were weakly associated with the other assessments. Weak correlations between interassessment variables indicated that little redundancy was present in the current clinical evaluations. Furthermore, reactive balance represents a unique domain of function that may improve the comprehensiveness of clinical assessments. [ABSTRACT FROM AUTHOR]

Objective: Unconstrained head motion is necessary to scan for visual cues during navigation, for minimizing threats, and to allow regulation of balance. Following mild traumatic brain injury (mTBI) people may experience alterations in head movement kinematics, which may be pronounced during gait tasks. Gait speed may also be impacted by the need to turn the head while walking in these individuals. The aim of this study was to examine head kinematics during dynamic gait tasks and the interaction between kinematics and gait speed in people with persistent symptoms after mTBI. Setting: A clinical assessment laboratory. Design: A cross-sectional, matched-cohort study. Participants: Forty-five individuals with a history of mTBI and 46 age-matched control individuals. Main Measures: All participants were tested at a single time point and completed the Functional Gait Assessment (FGA) while wearing a suite of body-mounted inertial measurement units (IMUs). Data collected from the IMUs were gait speed, and peak head rotation speed and amplitude in the yaw and pitch planes during the FGA-1, -3, and -4 tasks. Results: Participants with mTBI demonstrated significantly slower head rotations in the yaw (P =.0008) and pitch (P =.002) planes. They also demonstrated significantly reduced amplitude of yaw plane head rotations (P <.0001), but not pitch plane head rotations (P =.84). Participants with mTBI had significantly slower gait speed during normal gait (FGA-1) (P <.001) and experienced a significantly greater percent decrease in gait speed than healthy controls when walking with yaw plane head rotations (FGA-3) (P =.02), but not pitch plane head rotations (FGA-4) (P =.11). Conclusions: Participants with mTBI demonstrated smaller amplitudes and slower speeds of yaw plane head rotations and slower speeds of pitch plane head rotations during gait. Additionally, people with mTBI walked slower during normal gait and demonstrated a greater reduction in gait speed while walking with yaw plane head rotations compared with healthy controls. [ABSTRACT FROM AUTHOR]

Background and Purpose: The Functional Gait Assessment (FGA) and High Level Mobility Assessment Tool (HiMAT) are clinical batteries used to assess people with mild traumatic brain injury (mTBI). However, neither assessment was specifically developed for people with mTBI; the FGA was developed to evaluate vestibular deficits, and the HiMAT was developed for individuals with more severe TBI. To maximize the sensitivity and reduce the time burden of these assessments, the purpose of this study was to determine the combination of FGA and HiMAT items that best discriminates persons with persistent symptoms from mTBI from healthy controls. Methods: Fifty-three symptomatic civilians with persistent symptoms from mTBI (21% male, aged 31 (9.5) years, 328 [267] days since concussion) and 57 healthy adults (28% male, aged 32 (9.6) years) participated across 3 sites. The FGA and HiMAT were evaluated sequentially as part of a larger study. To determine the best combination of items, a lasso-based generalized linear model (glm) was fit to all data. Results: The area under the curve (AUC) for FGA and HiMAT total scores was 0.68 and 0.66, respectively. Lasso regression selected 4 items, including FGA Gait with Horizontal Head Turns and with Pivot Turn, and HiMAT Fast Forward and Backward Walk, and yielded an AUC (95% confidence interval) of 0.71 (0.61-0.79) using standard scoring. Discussion and Conclusions: The results provide initial evidence supporting a reduced, 4-Item Hybrid Assessment of Mobility for mTBI (HAM-4-mTBI) for monitoring individuals with mTBI. Future work should validate the HAM-4-mTBI and investigate its utility for tracking progression throughout rehabilitation. Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A409). [ABSTRACT FROM AUTHOR]

BACKGROUND: Little is known on the peripheral and central sensory contributions to persistent dizziness and imbalance following mild traumatic brain injury (mTBI). OBJECTIVE: To identify peripheral vestibular, central integrative, and oculomotor causes for chronic symptoms following mTBI. METHODS: Individuals with chronic mTBI symptoms and healthy controls (HC) completed a battery of oculomotor, peripheral vestibular and instrumented posturography evaluations and rated subjective symptoms on validated questionnaires. We defined abnormal oculomotor, peripheral vestibular, and central sensory integration for balance measures among mTBI participants as falling outside a 10-percentile cutoff determined from HC data. A X-squared test associated the proportion of normal and abnormal responses in each group. Partial Spearman's rank correlations evaluated the relationships between chronic symptoms and measures of oculomotor, peripheral vestibular, and central function for balance control. RESULTS: The mTBI group (n = 58) had more abnormal measures of central sensory integration for balance than the HC (n = 61) group (mTBI: 41% –61%; HC: 10%, p's < 0.001), but no differences on oculomotor and peripheral vestibular function (p > 0.113). Symptom severities were negatively correlated with central sensory integration for balance scores (p's < 0.048). CONCLUSIONS: Ongoing balance complaints in people with chronic mTBI are explained more by central sensory integration dysfunction rather than peripheral vestibular or oculomotor dysfunction. [ABSTRACT FROM AUTHOR]