New Paper published in "Next Research"

Anna M. Vogl, Lara K. Becker, Kirsten Liebetanz, Jule Zorn, Panagiota-Eirini Tsitou, Philipp Gulde

Abstract

Monitoring postural control in persons with multiple sclerosis (pwMS) is vital. Inertial measurement units (IMUs) could be a valid alternative to force plates. However, underlying findings often relate to difficult stances with low external validity, which may require an emphasized hip strategy that is uncommon in everyday life. Therefore, this study examined the validity and reliability of IMUs in an externally valid stance.
21 pwMS with mild-to-moderate disability and 19 healthy controls stood in an open parallel stance on a force plate for 20 s, holding a smartphone at the frontal waistline, twice with open and once with closed eyes. The average velocity (VEL) of the center of pressure (force plate) and the average acceleration (ACC) (smartphone) were tested for reliability and validity.
VEL (pwMS: ICC=0.83, p < 0.001; controls: ICC=0.71, p < 0.001) and ACC (pwMS: ICC=0.78, p < 0.001; controls: ICC=0.79, p < 0.001) were reliable. ACC did not show effects of group (pwMS vs. controls) (p = 0.794), condition (eyes open vs. closed) (p = 0.088, trend level ges=0.025), their interaction (p = 0.610), or age (p = 0.237). VEL revealed both group (p = 0.004, ges=0.072) and condition effects (p < 0.001, ges=0.215), but no interaction (p = 0.566); age was significantly associated (p < 0.001, ges=0.106). In both models, adding the respective other sway metric revealed significant associations of VEL and ACC (p = 0.018, ges=0.049).
The within-session reliability of the IMUs was confirmed. However, the validity of IMUs in pwMS with mild-to-moderate disability in an externally valid stance was not achieved, as the waist-worn IMUs primarily measure hip rather than ankle strategy.

Keywords

Multiple sclerosis; Postural control; Force plate; IMU; Reliability; Validity

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