Bell palsy: muscle reeducation by electromyograph feedback.

The present case study investigated the efficacy of feedback in restoring muscle control to facial muscles which had been affected by Bell palsy. The subject, a woman, was provided an analog tone as feedback for modifying the muscle activity on the paralyzed (right) side of her face to match that of her nonaffected (left) side. The results showed a statistically significant shift in muscle activity in masseter, zygomaticus, and orbicularis oculi muscles. Post-treatment levels closely approximated the nonaffected side, and resulted in more normal facial characteristics with respect to jaw position and symmetry of smiling. Bidirectional control of the zygomaticus was also demonstrated.