Quantitation of patterns of facial movement in patients with ocular to oral synkinesis.

As patients with facial paralysis regain facial nerve function, they must endure and adapt to complications associated with recovery, such as synkinesis. Synkinesis is the presence of unintentional movement in one area of the face when intentionally performing movement in another area of the face. We used the Maximal Static Response Assay of facial motion to better define the differences between eye closure-associated perioral motion in normal individuals, motion of the affected side in patients with synkinesis, and motion of the unaffected side in patients with synkinesis, thereby characterizing the syndrome of ocular to oral synkinesis. The study population consisted of 78 patients with clinically defined ocular to oral synkinesis of the left or right hemiface and 27 individuals without facial impairment (control subjects). We used the Maximal Static Response Assay to quantify facial motion on the affected and unaffected sides during the motions of eye closure and smile in both groups. Patients with ocular to oral synkinesis had decreased supraorbital and infraorbital motion of the orbicularis oculi during eye closure on both the affected and unaffected sides relative to control subjects. They also had increased modiolar motion during eye closure on both sides relative to control subjects. On the affected side, the modiolus tended to move laterally; on the unaffected side, the modiolus tended to move medially (i.e., toward the side affected by the synkinesis). Modiolar motion present during eye closure in patients with ocular to oral synkinesis was not statistically different from modiolar motion present during smile on the affected side (eye closure, 0.39 cm +/- 0.25; smile, 0.47 cm +/- 0.30, p > 0.05). Using the Maximal Static Response Assay, we have quantitatively defined synkinesis of the affected hemiface and have shown that movement of the unaffected hemiface is influenced by the synkinetic movements of the affected hemiface. These data may provide the basis for a rational system of facial neuromuscular rehabilitation in this patient group.