Evaluating the Responsiveness of Wearable-Based Motor Assessment for Stroke Upper-Limb Impairments

Stroke causes motor impairments in the upper limbs, significantly affecting stroke survivors' ability to perform daily activities. Rehabilitation is critical for motor recovery, and frequent assessments are crucial for monitoring improvements in motor impairment throughout the rehabilitation process. Wearable-based motor assessments offer the potential for frequent and objective monitoring of recovery trajectories. Particularly promising is the movement segmentation technique, which decomposes continuous wrist inertial data into lower-level units of upper-limb movements, grounded in theories of motor control and behavior. However, the technique's responsiveness to changes in motor function in stroke survivors has not yet been extensively studied. In this study, we investigate how inertial sensor data obtained during patients' continuous and task-free upper-limb movements can be processed to monitor the recovery trajectory in subacute stroke survivors as they undergo the recovery process. Our results showed that the variability of morphological shapes of the velocity profile of movement segments significantly correlated with changes in clinical scores on the Fugl-Meyer Assessment for the upper extremity (FMA-UE). Moreover, Receiver Operating Characteristic analysis demonstrated that this feature could distinguish participants who showed improvement based on minimal detectable changes, with an Area Under the Curve of 0.86 for FMA-UE. Our comprehensive analysis demonstrates that the movement segmentation approach offers the potential to support objective and frequent assessment of rehabilitation outcomes.