Estimating postural control with the balance rehabilitation unit: measurement consistency, accuracy, validity, and comparison with dynamic posturography.

OBJECTIVE: To examine the psychometric properties (test-retest reliability, concurrent validity, construct validity) of the Balance Rehabilitation Unit (BRU) during testing of sensory integration processes in healthy adults and individuals with vestibular disorders. DESIGN: Experimental cross-sectional design. SETTING: Clinic. PARTICIPANTS: Participants (N=90) included 30 subjects with vestibular disorders (age range, 18-85y), 30 young healthy adults (age range, 18-50y), and 30 older healthy adults (age range, 60-85y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Participants were tested twice with the BRU and once with the SMART EquiTest Sensory Organization Test (SOT). The center of pressure (COP) in the anteroposterior direction (COPap) and the COP in the mediolateral direction (COPml) were recorded. The COPap and COPml time series were used to estimate the area and velocity of the COP. RESULTS: The intraclass correlation coefficient of the COP area and velocity measures for the BRU for all subjects was at least .76 in all sensory organization conditions (P<.001). Significant correlations were found between the BRU and the SOT, ranging from .64 to .81 for COP area and from .44 to .76 for COP velocity. The older control group had significantly greater COP area and velocity compared with younger controls for the BRU and the SOT. The COP (area, velocity) was significantly higher for the younger individuals in the vestibular group than the younger controls. CONCLUSIONS: The reliability and validity of COP measurements obtained during testing of the sensory integration processes were demonstrated using the BRU. Future work should examine the responsiveness of these measures when individuals with balance disorders participate in rehabilitation.

Objective estimation of m-CTSIB balance test scores using wearable sensors and machine learning.

Accurate balance assessment is important in healthcare for identifying and managing conditions affecting stability and coordination. It plays a key role in preventing falls, understanding movement disorders, and designing appropriate therapeutic interventions across various age groups and medical conditions. However, traditional balance assessment methods often suffer from subjectivity, lack of comprehensive balance assessments and remote assessment capabilities, and reliance on specialized equipment and expert analysis. In response to these challenges, our study introduces an innovative approach for estimating scores on the Modified Clinical Test of Sensory Interaction on Balance (m-CTSIB). Utilizing wearable sensors and advanced machine learning algorithms, we offer an objective, accessible, and efficient method for balance assessment. We collected comprehensive movement data from 34 participants under four different sensory conditions using an array of inertial measurement unit (IMU) sensors coupled with a specialized system to evaluate ground truth m-CTSIB balance scores for our analysis. This data was then preprocessed, and an extensive array of features was extracted for analysis. To estimate the m-CTSIB scores, we applied Multiple Linear Regression (MLR), Support Vector Regression (SVR), and XGBOOST algorithms. Our subject-wise Leave-One-Out and 5-Fold cross-validation analysis demonstrated high accuracy and a strong correlation with ground truth balance scores, validating the effectiveness and reliability of our approach. Key insights were gained regarding the significance of specific movements, feature selection, and sensor placement in balance estimation. Notably, the XGBOOST model, utilizing the lumbar sensor data, achieved outstanding results in both methods, with Leave-One-Out cross-validation showing a correlation of 0.96 and a Mean Absolute Error (MAE) of 0.23 and 5-fold cross-validation showing comparable results with a correlation of 0.92 and an MAE of 0.23, confirming the model's consistent performance. This finding underlines the potential of our method to revolutionize balance assessment practices, particularly in settings where traditional methods are impractical or inaccessible.

Evaluating validity of the Kids-Balance Evaluation Systems Test (Kids-BESTest) Clinical Test of Sensory Integration of Balance (CTSIB) criteria to categorise stance postural control of ambulant children with CP.

PURPOSE: Evaluate the validity of the Clinical Test of Sensory Integration of Balance (CTSIB) scored using Kids-Balance Evaluation Systems Test (Kids-BESTest) criteria compared to laboratory measures of postural control. METHOD: Participants were 58 children, 7-18 years, 17 with ambulant cerebral palsy (CP) (GMFCS I-II), and 41 typically developing (TD). Postural control in standing was assessed using CTSIB items firm and foam surfaces, eyes open (EO) then closed (EC). Face validity was evaluated comparing clinical Kids-BESTest scores between groups. Correlating force plate centre-of-pressure (CoP) data and clinical scores allowed evaluation of concurrent and content validity. RESULTS: Face validity: TD children scored higher for all CTSIB conditions when compared to children with CP. Concurrent validity: the agreement between clinical and CoP derived scores was poor to excellent (Firm-EO = 76%, Firm-EC = 76%, Foam-EO = 59%, Foam-EC = 94%). Clinical scores of "2-unstable" and "3-stable" were not distinguished reliably by force plate measures. Content validity: significant correlations were found between clinical scores and CoP data for the two intermediate conditions (Firm-EC: rs -0.40 to -0.72; Foam-EO: rs -0.12 to -0.50), but not the easier (Firm-EO: rs -0.41 to -0.36) or harder conditions (Foam-EC: rs -0.25 to -0.27). CONCLUSION: Face validity of Kids-BESTest CTSIB criteria was supported. Content and concurrent validity were partially supported. Improved Kids-BESTest scoring terms were recommended to describe postural characteristics of "2-unstable."IMPLICATIONS FOR REHABILITATIONFace validity of the Kids-BESTest criteria for the CTSIB was confirmed.The Kids-BESTest criteria for the CTSIB can identify children with atypical postural control.Concurrent validity and content validity were partially supported, since children with CP resorted to a range of different balance strategies when "unstable."To improve CTSIB Kids-BESTest criteria, new terms were recommended to better describe postural characteristics of "2-unstable."

Vibrotactile Feedback Alters Dynamics Of Static Postural Control In Persons With Parkinson's Disease But Not Older Adults At High Fall Risk.

BACKGROUND: Aging and Parkinson's disease are often associated with impaired postural control. Providing extrinsic feedback via vibrotactile sensation could supplement intrinsic feedback to maintain postural control. RESEARCH QUESTION: We investigated the postural control response to vibrotactile feedback provided at the trunk during challenging stance conditions in older adults at high fall risk and individuals with Parkinson's disease compared to healthy older adults. METHODS: Nine older adults at high fall risk, 9 persons with Parkinson's disease and 10 healthy older adults performed 30s quiet standing on a force platform under five challenging stance conditions with eyes open/closed and standing on firm/foam surface with feet together, each with and without vibrotactile feedback. During vibrotactile feedback trials, feedback was provided when participants swayed >10% over the center of their base of support. Participants were instructed vibrations would be in response to their movement. Magnitude of postural sway was estimated using center of pressure path length, velocity, and sway area. Dynamics of individuals' postural control was evaluated using detrended fluctuation analysis. RESULTS: Results showed that vibrotactile feedback induced a change in postural control dynamics among persons with Parkinson's disease when standing with intact intrinsic visual input and altered intrinsic somatosensory input, but there was no change in sway magnitude. However, use of vibrotactile feedback did not significantly alter dynamics of postural control in older adults with high risk of falling or reduce the magnitude of sway. SIGNIFICANCE: Considering the effects of vibrotactile feedback were dependent on the population and stance condition, designing an optimal therapeutic regimen for balance training should be carefully considered and be specific to a target population. Furthermore, our results suggest that explicit instructions on how to respond to the vibrotactile feedback could affect training outcome.

Visual dependence and spatial orientation in benign paroxysmal positional vertigo.

People with benign paroxysmal positional vertigo (BPPV) probably have otoconial particles displaced from the utricle into the posterior semicircular canal. This unilateral change in the inertial load distributions of the labyrinth may result in visual dependence and may affect balance control. The goal of this study was to explore the interaction between visual dependence and balance control. We compared 23 healthy controls to 17 people with unilateral BPPV on the Clinical Test of Sensory Interaction and Balance on compliant foam with feet together, the Rod-and-Frame Test and a Mental Rotation Test. In controls, but not BPPV subjects, subjects with poor balance scores had significantly greater visual dependence, indicating that reliance on visual cues can affect balance control. BPPV and control subjects did not differ on the mental rotation task overall but BPPV reaction time was greater at greater orietantions, suggesting that this cognitive function was affected by BPPV. The side of impairment was strongly related to the side of perceived bias in the Earth vertical determined by BPPV subjects, indicating the relationship between the effect of asymmetric otolith unloading with simultaneous canal loading on spatial orientation perception.