Corticomuscular integrated representation of voluntary motor effort in robotic control for wrist-hand rehabilitation after stroke.

Abstract

<i>Objective.</i>The central-to-peripheral voluntary motor effort (VME) in the affected limb is a dominant force for driving the functional neuroplasticity on motor restoration post-stroke. However, current rehabilitation robots isolated the central and peripheral involvements in the control design, resulting in limited rehabilitation effectiveness. This study was to design a corticomuscular coherence (CMC) and electromyography (EMG)-driven control to integrate the central and peripheral VMEs in neuromuscular systems in stroke survivors.<i>Approach.</i>The CMC-EMG-driven control was developed in a neuromuscular electrical stimulation (NMES)-robot system, i.e. CMC-EMG-driven NMES-robot system, to instruct and assist the wrist-hand extension and flexion in persons after stroke. A pilot single-group trial of 20 training sessions was conducted with the developed system to assess the feasibility for wrist-hand practice on the chronic strokes (16 subjects). The rehabilitation effectiveness was evaluated through clinical assessments, CMC, and EMG activation levels.<i>Main results.</i>The trigger success rate and laterality index of CMC were significantly increased in wrist-hand extension across training sessions (<i>p</i>< 0.05). After the training, significant improvements in the target wrist-hand joints and suppressed compensation from the proximal shoulder-elbow joints were observed through the clinical scores and EMG activation levels (<i>p</i>< 0.05). The central-to-peripheral VME distribution across upper extremity (UE) muscles was also significantly improved, as revealed by the CMC values (<i>p</i>< 0.05).<i>Significance.</i>Precise wrist-hand rehabilitation was achieved by the developed system, presenting suppressed cortical and muscular compensation from the contralesional hemisphere and the proximal UE, and improved distribution of the central-and-peripheral VME on UE muscles. ClinicalTrials.gov Register Number NCT02117089.