Evaluating Activity Levels in Individuals with TBI using IMU.

Traumatic Brain Injury (TBI) is one of the leading causes of sensorimotor deficits in adults and often results in gait deficits. In this context, inertial measurement units (IMU) have emerged as an effective tool for objectively quantifying activity levels. This work evaluates IMU-derived activity levels using activity counts from ankles, wrists, and sacrum during walking and stair climbing tasks in individuals with TBI and healthy controls, and relates these counts to functional measures (timed up and go, dynamic gait index, and gait speed). Results show that TBI participants had reduced activity levels at the ankles compared to healthy controls during walking, but there were no appreciable differences for sensors placed at the wrist or sacrum. Additionally, the correlation patterns between activity levels and functional measures were distinct for the TBI and healthy control groups. The results suggest that activity counts, as an aggregate measure of physical activity levels, can reveal activity differences between TBI and healthy control groups, but sensor location is a critical parameter.