We examined the relationship between the time course of development of facial synkinesis in patients with Bell's palsy and the severity of facial nerve damage.
Tertiary referral center.
Thirty-nine consecutive patients with Bell's palsy who developed synkinesis.
Subjects were divided into groups A (electroneurographic [ENoG] value, <10%; n = 31) and B (ENoG value, ≥10%; n = 8). Development of facial synkinesis was assessed based on the appearance of synkinetic potentials from the orbicularis oris muscle on the blink reflex test. Times to appearance of facial synkinesis in groups A and B were compared. The proportion of patients who developed facial synkinesis after complete recovery of facial movement was also assessed in 14 patients whose facial movement recovered completely.
The mean time to maximal recovery of facial movement was significantly longer in group A than in group B (p < 0.001), whereas the duration between the appearance of facial synkinesis and the onset of facial paralysis did not differ significantly between the 2 groups (p = 0.72). The proportion of patients who developed facial synkinesis after complete recovery of facial movement was significantly greater in group B than in group A (p = 0.015).
During the course of recovery from Bell's palsy, the patients with an ENoG value of 10% or greater have a higher risk of developing facial synkinesis after complete recovery of facial movement.
*Department of Otolaryngology, Faculty of Medicine, and †Department of Clinical Trial Data Management, Graduate School of Medicine, University of Tokyo, Tokyo; and ‡Department of Otolaryngology, Hitachi General Hospital, Ibaraki, Japan
Address correspondence and reprint requests to Kaori Kanaya, M.D., Department of Otolaryngology, Graduate School of Medicine, University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan; E-mail: email@example.com
The authors have no grant, financial support and conflicts of interest to this report.