Objective Computerized versus Subjective Analysis of Facial Synkinesis

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Abstract
To compare the sensitivity of an objective, computerized approach to measurement of facial synkinesis with that for a subjective approach and to examine the test-retest reliability of these approaches. Prospective, nonrandomized, and blinded. Remote facial motion at the upper eyelids and oral commissures during a closed-lip smile and eyelid closure were measured using a commercially available computerized motion analysis system. Thirty healthy adults with normal facial nerve function were enrolled to establish normative data and a threshold value for synkinesis. Thirty consecutive patients were analyzed based on the synkinesis threshold value. Blinded subjective evaluations by two observers were also performed independently on the same patients. Facial synkinesis was detected significantly more frequently with objective than subjective analysis for eyelid closure; no significant differences between approaches were shown for the closed-lip smile. Interestingly, five (17%) patients developed early synkinesis within 3 months from the onset of the facial nerve injury. The test-retest reliability of all objective measures was excellent for both expressions. Close agreement in percent of patients with synkinesis between test and retest subjective evaluations was obtained for both observers for both expressions. The objective, computerized approach to detection of facial synkinesis has excellent reliability and is more sensitive than the subjective approach to assessment to the presence of facial synkinesis associated with eyelid closure. The finding of early synkinesis suggests that central nervous reorganization plays a role in regeneration of the facial nerve.