Kinematic Validation of Postural Sway Measured by Biodex Biosway (Force Plate) and SWAY Balance (Accelerometer) Technology.

Birendra M Dewan,Steven F Sawyer,Neeraj A Kumar,C Roger James

doi:10.1155/2019/8185710

Birendra M Dewan, Steven F Sawyer + Show 2 more

Open Access

https://doi.org/10.1155/2019/8185710

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Abstract

Background The Biodex Biosway® Balance System and SWAY Balance® Mobile smartphone application (SBMA) are portable instruments that assess balance function with force plate and accelerometer technology, respectively. The validity of these indirect clinical measures of postural sway merits investigation. Purpose The purpose of this study was to investigate the concurrent validity of standing postural sway measurements by using the portable Biosway and SBMA systems with kinematic measurements of the whole body Center of Mass (COM) derived from a gold-standard reference, a motion capture system. Study Design Cross-sectional; repeated measures. Methods Forty healthy young adults (21 female, 19 male) participated in this study. Participants performed 10 standing balance tasks that included combinations of standing on one or two legs, with eyes open or closed, on a firm surface or foam surface and voluntary rhythmic sway. Postural sway was measured simultaneously from SBMA, Biosway, and the motion capture system. The linear relationships between the measurements were analyzed. Results Significant correlations were found between Biosway and COM velocity for both progressively challenging single and double leg stances (τb = 0.3 to 0.5, p < 0.01 to <0.0001). SBMA scores and COM velocity were significantly correlated only for single leg stances (τb = −0.5 to −0.6, p < 0.0001). SBMA scores had near-maximal values with zero to near-zero variance in double leg stances, indicating a ceiling effect. Conclusion The force plate-based Biodex Biosway is valid for assessing standing postural sway for a wide range of test conditions and challenges to standing balance, whereas an accelerometer-based SWAY Balance smartphone application is valid for assessing postural sway in progressively challenging single leg stance but is not sensitive enough to detect lower-magnitude postural sway changes in progressively challenging double leg stances.

Highlights

Postural sway is an important metric that provides information about balance function, postural control, and risks of falls
It usually includes a set of standing balance test protocols and recording of postural sway with an objective instrumentation under controlled conditions [3]. e 3-dimensional (3D) motion capture system (MOCAP) is considered a gold-standard reference for the assessment of postural stability which offers a high level of accuracy and reliability necessary to record small motions [4,5,6]
Mean ± standard deviation of SWAY Balance Mobile Application (SBMA) scores, Biosway Sway Index (SI), Biosway SI divided by Base of Support (BOS), and Center of Mass (COM) Balance indices (COM SI/BOS and COM velocity/BOS) for conditions C1 through C10

Summary

Research Article

Kinematic Validation of Postural Sway Measured by Biodex Biosway (Force Plate) and SWAY Balance (Accelerometer) Technology. E Biodex Biosway Balance System and SWAY Balance Mobile smartphone application (SBMA) are portable instruments that assess balance function with force plate and accelerometer technology, respectively. E purpose of this study was to investigate the concurrent validity of standing postural sway measurements by using the portable Biosway and SBMA systems with kinematic measurements of the whole body Center of Mass (COM) derived from a gold-standard reference, a motion capture system. E force plate-based Biodex Biosway is valid for assessing standing postural sway for a wide range of test conditions and challenges to standing balance, whereas an accelerometer-based SWAY Balance smartphone application is valid for assessing postural sway in progressively challenging single leg stance but is not sensitive enough to detect lower-magnitude postural sway changes in progressively challenging double leg stances Conclusion. e force plate-based Biodex Biosway is valid for assessing standing postural sway for a wide range of test conditions and challenges to standing balance, whereas an accelerometer-based SWAY Balance smartphone application is valid for assessing postural sway in progressively challenging single leg stance but is not sensitive enough to detect lower-magnitude postural sway changes in progressively challenging double leg stances

Introduction

Methods

SBMA score

Results

Between groups Within groups