Measuring Mobility with Inertia Measurement Units
Bergmann J.H.M., Mayagoitia R.E., Smith I.C.H.
Applied Biomedical Division, King’s College London, Guy’s Campus, London SE1 1UL, UK
In self-rated health, the most important activities of daily living are those involving mobility [1]. Obtaining accurate data about mobility is therefore clinically relevant. Self-reported difficulty in stair climbing has shown to be useful in assessing and defining functional status of older adults [2], while basic mobility is often assessed by the Timed Up and Go test (TUG) [3]. In general, kinematics and biomechanical aspects of stair climbing are studied using laboratory staircases and optical motion analysis systems. Although this kind of research yields valuable information, the results only remain valid when no anticipation or reaction to a real-world environment is required. We have measured joint angles and initial contacts during stair climbing (n=14) using a portable system of inertial measurement units (IMUs) and found that this method related well to measurements obtained with an optical tracking device (Pearson’s Correlations > 0.92, p< 0.01). Basic mobility was further investigated (n=28) by using IMUs to measure TUG performance of healthy young and older adults. By utilizing a quantitative method, we were able to split up the TUG into components (standing up, walking, turning, etc.). We found that turning time appeared to be the best component to distinguish between the two age groups (ANOVA, Bonferroni, p< 0.01). Whereas, standing up time did not seem to differ between the two groups. In general, we can conclude that these highly portable body-worn inertial sensors can be used by clinicians and researchers alike, to accurately collect data regarding mobility in complex real-life situations.
Support
This work was funded by a joint Medical Research Council and Graduate School Studentship of King’s College London.
References
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