A Soft, Flexible Skin-Mounted Sensor for Monitoring Balance Deficits in People with Multiple Sclerosis
Objectives: Here we applied a lightweight, wireless, flexible, skin-mounted inertial sensor system (BioStampRC®, MC10 Inc.) to objectively assess the balance performance of PwMS (with and without a history of falling) and healthy control subjects.
Methods: Participants were divided into groups based on presence of MS and self-reported fall history (healthy controls, non-faller, n=12: 7 females, 58.1 ± 13.5 yrs; MS non-faller, n=23: 19 females, 56.3 ± 10.9 yrs, EDSS 3.0 ± 2.5; and MS recurrent faller n=17: 9 females, 59.1 ± 8.9 yrs, EDSS 5.0 ± 2.0, >= 2 falls in the past 6 months). The balance assessment consisted of two 30-second trials in three conditions: eyes open/firm surface (EO), eyes closed/firm surface (EC), and eyes open/foam surface (FEO). Postural sway was measured with a BioStampRC® sensor placed on the posterior trunk at L5. Postural sway measurements (sway jerk, sway amplitude, and sway frequency) were derived from the acceleration, and compared between groups and conditions using a repeated measure ANOVA.
Results: The balance challenging conditions (EC/FEO) elicited greater sway jerk and sway amplitude than EO condition across all participants group (p < 0.05). The MS-fall group exhibited significantly greater sway jerk (p=0.03) and sway amplitude (p = 0.02) than the control, while the MS no-fall group revealed no significant difference between the other groups. Sway frequency measured by BioStampRC®was insensitive to group and condition (p > 0.05).
Conclusions: This study demonstrated that a single skin-mounted inertial sensor (BioStampRC®) can detect balance deficits in persons with MS with a history of falls. Future work is needed to examine whether body motion quantified by skin-mounted inertial sensors are predictive of falls.