Comparison of facial synkinesis at 6 and 12 months after the onset of peripheral facial nerve palsy.

OBJECTIVE

To investigate the time course of synkinesis as a sequela of facial nerve palsy so that we are able to determine an appropriate time for deciding the outcome of recovery in patients with facial nerve palsy.

METHODS

Nineteen consecutive patients with peripheral facial nerve palsy who developed synkinesis were enrolled. We compared the degree of synkinesis at 6 and 12 months after the onset of palsy. Our investigation consisted of (1) scoring using the Sunnybrook facial grading system and (2) computing the asymmetry (%) in eye opening width. We also judged whether all 19 cases were cured or not based on the treatment outcome criteria of the Japan Society of Facial Nerve Research at 6 and 12 months.

RESULTS

The synkinesis score based on Sunnybrook facial grading system and the degree of asymmetry in eye opening width during mouth movement deteriorated significantly between the 6th and 12th month after the onset of palsy. One of the cases regarded as "cured" at the 6th month was later judged to be "non-cured" due to deterioration in the synkinesis score at the 12th month.

CONCLUSION

From our results, synkinesis deteriorated after the 6th month from the onset of palsy. Therefore, we should follow up the degree of synkinesis until at least the 12th month, and the outcome of recovery in patients with facial synkinesis should be evaluated at least 12 months after the onset.