Symmetry and synkinesis during rehabilitation of unilateral facial paralysis.

We evaluated biofeedback rehabilitation in patients with severe chronic unilateral facial paralysis, who had intact facial-motor innervation (House grades 3 to 5). Recovery of facial function was characterized (1) by grading facial movement symmetry, and (2) by counting the number of muscles exhibiting synkinesis during maximal execution of selected facial movements (e.g., smiling). Facial function in 21 patients typically improved by one House grade. Facial symmetry recovered rapidly during the first 5 months of treatment, and then improved more slowly. However, during this latter period, examination of the relationship between symmetry and synkinesis (visualized by a graph plotting symmetry grades on the x-axis, against the number of synkinetic muscles on the y-axis) indicated that overall facial control was improving even when House grading suggested that it was not. Such information should aid facial retraining and may clarify understanding of underlying rehabilitation mechanisms.