Measuring Upper-Extremity Use with One IMU

Discharge home from hospital can be a critical stage in the rehabilitation of patients with central neurological disorders such as stroke. The new skills and early recovery achieved in the hospital may be difficult to transfer to the home environment. This work addresses the monitoring of arm usage and proposed a new metric called Weighted Activity Counts (WAC) based on a sensing system that consists of only one inertial measurement unit (IMU). The proposed metric combines activity counts and the smoothness of the movement. This work defines Normalized Gross Energy Expenditure (NGEC) as the reference metric. WAC shows good performance under the validation protocol we designed (correlation coefficient r > 0:90). The optimal placement for the single sensor which can sufficiently and reliably describe arm usage is also explored in this work.