Muscle Synergies in Chronic Stroke during a Robot-Assisted Wrist Training

The motor recovery procedure during robot-assisted wrist rehabilitation for persons after stroke has not been well studied previously. In this work, we analyzed the variations in the muscular co-activation patterns related to the wrist and elbow motions in hemiplegic persons with chronic stroke (n=4) during a 20-session´s interactive robot-assisted training. Significant decreases in muscle cocontractions (P<0.05) for all muscle pairs were observed, which was mainly due to the reduction in the muscle activation levels. Improvements were also found in motor functions assessed by clinical scales before and after the training. The results suggested an increased selective control on individual muscles for both wrist and elbow joints in a designed task after the robot-assisted training.