[Electrophysiological study of Bell's palsy in children].

An electrophysiological study of Bell's palsy in children was reported. Direct response to facial nerve stimulation was tested in 28 patients. Of these, 17 patients were further tested for electrically elicited blink reflex. The reduction in amplitude of direct response on affected side was characteristic of Bell's palsy. The direct response was evoked on affected as well as nonaffected side. The amplitude of the direct response on the affected side was expressed as percentage of that on the nonaffected side (ratio of M response amplitude:RMA). 13 patients showed incomplete recovery after 3 months, and RMA of the 11 patients of them were reduced below 30%. In the patients showing good clinical recovery within 2 months, RMA returned to normal promptly. In the blink reflex, R1 R2 components were found to be persistent on the first examination, suggesting a satisfactory functional outcome in Bell's palsy. As these electrophysiological methods are conventional assessing facial nerve function, it seemed to be valuable for the follow up of children with Bell's palsy.