Using wearable inertial sensors to detect different strategies for the sit-to-stand transition in multiple sclerosis

INTRODUCTION: The sit-to-stand (Si-St) transition is an essential activity of daily living (ADL) which is fundamental to maintaining functional independence. It can often be compromised in patients with neurological disorders such as multiple sclerosis (MS). OBJECTIVE: The aim of the current study was to determine if different strategies can be detected in the performance of the sitto-stand transition using gyroscope metrics from wearable inertial sensors in MS and healthy participants. METHODS: 12 ambulatory persons with MS (PwMS) with an EDSS of 1-5.5 were compared with 11 healthy volunteers. Participants performed a Si-St transition and a Timed 25 Foot Walk (T25FW) while fitted with wearable inertial sensors (x-io NGIMU) on the thigh and sternum. Each sensor node recorded 9 channels of data (3 each of accelerometers, gyroscopes, and magnetometers) over Wi-Fi onto a computer using software provided by the manufacturer. Analysis of wave forms was done using Matlab and peak detection algorithms based on a 6 Hz low pass filter of the signal. RESULTS: The effect of disability on the Si-St transition was that the peak of thigh pitch angular velocity was lower in PwMS than the healthy volunteers (p=0.045, Cliff’s d = 0.500). The average duration of the momentum transfer phase of sit-to-stand was longer in PwMS in comparison to healthy (p=0.039, Cliff’s delta=0.515). The duration of momentum transfer was strongly correlated with peak thigh angular velocity but only weakly correlated with T25FW performance or the patient reported measures of disability (MSWS-12 and EDSS-s). CONCLUSION: The durations of momentum transfer derived from inertial sensor measurements reflect different movement strategies used by PwMS and healthy individuals for getting out of a chair.