Electromyography as an Objective Outcome Measure for the Therapeutic Effect of Biofeedback Training to Reduce Post-Paralytic Facial Synkinesis

Abstract

Biofeedback rehabilitation for facial palsy is not yet routinely available for patients. Methods: To improve evidence, the effect of an intensive two-week facial training combining electromyography (EMG) and visual biofeedback training of 30 patients (76.7% female; median age: 48.6 years) with post-paralytic facial synkinesis was objectively evaluated. At the beginning of each training day, EMG amplitudes of both halves of the face were recorded during relaxation using the EMG system that was synchronously used for the EMG biofeedback training. A single-factor analysis of variance was performed for the change over time, and a t-test was used to evaluate the side differences. Results: At the end of the training program, there was a significant decrease in the EMG amplitudes of both halves of the face (synkinetic side: p < 0.001; contralateral side p = 0.003), indicating an improved voluntary muscle relaxation. There was also a significant improvement in Sunnybrook Facial Grading System, Facial Disability Index and Facial Clinimetric Evaluation scores, which were assessed before the start of training and at the end (p < 0.001). Conclusion: Electrophysiological improvements can be objectively measured using surface EMG.