EMG-Triggered Functional Electrical Stimulation for Central Facial Palsy Following Stroke: A Clinical Case Report

Background: Central facial palsy (CFP) is a common condition following stroke, typically affecting the lower face and causing symptoms such as drooling, dysarthria, and facial asymmetry. Despite available rehabilitation methods, the evidence supporting their effectiveness is limited. Electromyography (EMG)-triggered Functional Electrical Stimulation (FES) has shown promise in neurorehabilitation for motor impairments, but its application to CFP remains unclear. Methods: This case report explores the use of EMG-triggered FES in a 77-year-old patient with CFP following a severe ischemic stroke of the middle cerebral artery (MCA). Therapy, focused on stimulating the orbicularis oris muscle to address persistent drooling and improve facial symmetry, was alongside usual care. The stimulation duration was 5-15 min, frequency 35 Hz, and pulse duration 300 µs, applied 5 times a week. Stimulation duration was adjusted based on the patient's progress. Results: The patient underwent 16 sessions of EMG-triggered FES over four weeks. Post-therapy reassessment with the Sunnybrook Facial Grading System (SFGS) showed an improvement in facial motor function, with the score increasing from 58/100 to 78/100. Reassessment of the Facial Disability Index (FDI) revealed significant improvement in physical function (55 to 85 points), though the social function score slightly decreased (76 to 64 points). Improvements in dysarthria and the complete resolution of drooling were reflected in the physical function domain of the FDI and the Allensbach Dysarthria Severity Scale. Conclusions: The results highlight that EMG-triggered FES was well tolerated and effectively supported therapy, contributing to the resolution of drooling, improved facial symmetry, and enhanced speech function. Future research should focus on randomized controlled trials to confirm its effectiveness and determine optimal therapy parameters.