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bioRxiv · 10.1101/2020.05.29.123620

Validation of a smartphone embedded inertial measurement unit for measuring postural stability in older adults

De Groote, F.·Vandevyvere, S.·Vanhevel, F.·Orban de Xivry, J.-J.
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Abstract

BackgroundIdentifying older adults with increased fall risk due to poor postural control on a large scale is only possible through omnipresent and low cost measuring devices such as the inertial measurement units (IMU) embedded in smartphones. However, the correlation between smartphone measures of postural stability and state-of-the-art force plate measures has never been assessed in a large sample allowing us to take into account age as a covariate. Research questionHow reliably can postural stability be measured with a smartphone embedded IMU in comparison to a force plate? MethodsWe assessed balance in 97 adults aged 50 to 90 years in four different conditions (eyes open, eyes closed, semi-tandem and dual-task) in the anterio-posterior and medio-lateral directions. We used six different parameters (root mean square and average absolute value of COP displacement, velocity and acceleration) for the force plate and two different parameters (root mean square and average absolute value of COM acceleration) for the smartphone. ResultsTest-retest reliability was smaller for the smartphone than for the force plate (intra class correlation) but both devices could equally well detect differences between conditions (similar Cohens d). Parameters from the smartphone and the force plate, with age regressed out, were moderately correlated (robust correlation coefficients of around 0.5). SignificanceThis study comprehensively documents test-retest reliability and effect sizes for stability measures obtained with a force plate and smartphone as well as correlations between force plate and smartphone measures based on a large sample of older adults. Our large sample size allowed us to reliably determine the strength of the correlations between force plate and smartphone measures. The most important practical implication of our results is that more repetitions or longer trials are required when using a smartphone instead of a force plate to assess balance. HighlightsO_LIWe compared balance measures simultaneously obtained from a phone and a force plate C_LIO_LIFor precision purposes, we included a large group of older participants (N=97). C_LIO_LIUsing age as covariate, we found a moderate correlation across the two devices. C_LIO_LIIntra-class correlation coefficients were smaller for the smartphone. C_LIO_LIBalance assessment with smartphones requires longer trials compared to force plates. C_LI

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De Groote, F., Vandevyvere, S., Vanhevel, F., Orban de Xivry, J.-J.. 2020-05-31. Validation of a smartphone embedded inertial measurement unit for measuring postural stability in older adults. https://doi.org/10.1101/2020.05.29.123620

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