Neuromodulatory effects of voluntary-motor-effort-driven wrist-hand robot in sensorimotor dynamics after stroke
摘要
Voluntary motor effort (VME)-driven neuromuscular electrical stimulation (NMES)-robots have demonstrated superior rehabilitative efficacy in post-stroke wrist–hand motor restoration compared with purely mechanical systems. However, their neuromodulatory mechanisms remain unclear. This study aimed to investigate cortical responses elicited by an electromyography (EMG)-driven NMES-robot assisting wrist–hand movements in individuals with chronic stroke, and to evaluate robot-nervous system interactions, using EMG to capture VME.
MethodsCortical responses during wrist–hand extension were recorded in participants with chronic stroke (n = 18) and unimpaired controls (n = 20) using functional near-infrared spectroscopy (fNIRS). The EMG-driven NMES-robot delivered somatosensory stimulation with different combinations of mechanical stimulation (MS) to the targeted joints and NMES to the forearm muscles, with or without VME.
ResultsCombined MS and NMES co-stimulation activated wider cortical areas than MS or NMES alone in both groups. Compared with the unimpaired group, the stroke group exhibited greater ipsilesional activations in response to NMES (p < 0.05), while MS induced comparable activations in the contralateral hemisphere to the stimulated limb in both groups (p < 0.05). When VME was required, the stroke group exhibited wider contralesional involvement with MS only (p < 0.05) but reduced contralesional involvement during sole NMES (p < 0.05), compared to those in the co-stimulation. Additionally, the MS and NMES co-stimulation resulted in similar functional connectivity patterns between the stroke and unimpaired groups.
ConclusionCombined mechano-electrical somatosensory co-stimulation with MS and NMES to the affected wrist-hand, when voluntary motor effort is generated from the residual muscles, could elicit extensive cortical activation approaching normal patterns.
Trial registrationChinese Clinical Trial Registry with the identifier ChiCTR2200057839.