Using socially assistive robotics to augment motor task performance in individuals post-stroke

Abstract

This paper presents an application of a socially assistive robotics (SAR) system to hands-off post-stroke rehabilitation. We validate the technical feasibility and efficacy of our system in guiding, motivating, and administering an upper extremity rehabilitation task. The robot, which consists of a humanoid torso on a mobile base, monitors user performance on a wire puzzle task through a wearable inertial measurement unit and signals from the puzzle. Smoothness of stroke-affected limb movement is used as the evaluation metric. Five adults of mild to moderate functional ability in the chronic phase of stroke recovery interacted with our SAR system over three separate days. The inertial data from the five participants were analyzed using frequency domain techniques. Subsequently, the amount of power in frequency bands corresponding to voluntary (0.1 to 2Hz) and involuntary motion/jerk (4 to 8Hz) was evaluated. We found that, in adults of mild severity (Upper Extremity Fugl-Meyer Assessment scores greater than 40), the motion becomes smoother (the amount of jerk is reduced) over 3 days of task practice. In adults of moderate motor severity (scores below 40), the motion became less smooth. This may indicate that the combination of our task and SAR system is better suited for individuals with higher functional ability, and needs augmentation in order to aid those of lower functional ability levels.