The effects of electromyography-controlled functional electrical stimulation on upper extremity function and cortical perfusion in stroke patients

• Near-infrared spectroscopy (NIRS) is feasible in measuring brain activity during the electrical stimulation which is not available with fMRI.
• With analysis of brain cortical perfusion (BCP) using NIRS during rehabilitative training of a paretic upper extremity, the relationship between EMG-controlled FES (EMG-FES) therapy and ipsilesional BCP was revealed.
• This is the first article describing the brain perfusion change during EMG-FES stimulation and its treatment benefits for the hemiparetic patients in rehabilitation course.

ObjectiveThe relation was investigated between hemiparetic arm function improvement and brain cortical perfusion (BCP) change during voluntary muscle contraction (VOL), EMG-controlled FES (EMG-FES) and simple electrical muscle stimulation (ES) before and after EMG-FES therapy in chronic stroke patients.MethodsSixteen chronic stroke patients with moderate residual hemiparesis underwent 5 months of task-orientated EMG-FES therapy of the paretic arm once or twice a week. Before and after treatment, arm function was clinically evaluated and BCP during VOL, ES and EMG-FES were assessed using multi-channel near-infrared spectroscopy.ResultsBCP in the ipsilesional sensory-motor cortex (SMC) was greater during EMG-FES than during VOL or ES; therefore, EMG-FES caused a shift in the dominant BCP from the contralesional to ipsilesional SMC. After EMG-FES therapy, arm function improved in most patients, with some individual variability, and there was significant improvement in Fugl–Meyer (FM) score and maximal grip strength (GS). Clinical improvement was accompanied by an increase in ipsilesional SMC activation during VOL and EMG-FES condition.ConclusionThe EMG-FES may have more influence on ipsilesional BCP than VOL or ES alone.SignificanceThe sensory motor integration during EMG-FES therapy might facilitate BCP of the ipsilesional SMC and result in functional improvement of hemiparetic upper extremity.