末梢性顔面神経麻痺における電気生理学的診断法の検討

(第1報 臨床編)

抄録

Electroneurography (ENoG) is an electrophysiological diagnostic method for predicting the prognosis of peripheral facial palsy. It provides an electric stimulation to the facial nerve from the stylomastoid foramen and records mainly the orbicularis oris muscle contraction by surface electrodes, and the prognosis is evaluated in terms of the ratio of the amplitude of the normal side to that of the lesion side (ENoG value). In 175 patients with Bell's palsy seen within 2 weeks after the onset and given a conservative therapy in our department, recovery of the facial movement (May's score modified by Hosomi) at 1, 2 and 6 months after the onset and the appearance of sequelae were examined. Diagnostic criteria of the prognosis were formulated on the basis of the ENoG values within 2 weeks after the onset.
The criteria indicated that patients with an ENoG value above 40% almost recovered within a month without any sequela, those with an ENoG value of 20-39% almost recovered within 2 months with a 1/10 incidence of sequela and those with an ENoG value of 5-19% recovered in many cases within 6 months. The incidence of sequela was 1/5 for those with al ENoG value above 10% and 1/2 for those with an ENoG value below 10%. In patients with an ENoG value of 0-4%, the ENoG value was mostly 0% without sufficient recovery even after 6 months in whom the sequela amounted to 1/2.
The present criteria provide a larger advantage for precise evaluation than the conventional Esslen's criteria in that the former permits more patient distribution of cases, detailed assessment of the prognosis and quantification of the incidence of sequela. It was also found that 10-19% was a clinical critical limit below which a complete recovery was not expected.