Use of electroneurography as a prognostic indicator of Bell's Palsy in Chinese patients

To evaluate the use of electroneurography (ENOG) as a prognostic indicator in Bell's Palsy for Chinese patients in Hong Kong. Prospective study. Tertiary referral outpatient center. Sixty-three consecutive patients with a diagnosis of Bell's Palsy in Tuen Mun Hospital, Hong Kong, from January 1995 to January 1998. ENOG, protective eye care, and exercise of the facial muscles. ENOG was performed 5 to 14 days after the onset of facial palsy. The recovery of facial nerve function was documented by House and Brackmann grading. All the patients were followed up monthly until recovery or up to 6 months. Sixty-three patients were randomly divided into two groups of 32 and 31 patients. The first part of the study was to analyze the correlation between ENOG values and the chance of recovery in Group 1 patients (n = 32) by means of a logistic regression model. The result showed that patients with ENOG values less than 72.63% had a greater than 90% chance of recovery to House Grade II or better within 2 months (Wald = 6.19, p < 0.05). The second part of the study was to assess the capability of this ENOG value to accurately predict the prognosis of Bell's Palsy in Group 2 patients (n = 31) using Fisher's exact test (p < 0.0001). The sensitivity and specificity of ENOG in predicting a good prognosis (recovery to House Grade III or better after 2 months) in patients with Bell's Palsy were 82% and 100%, respectively. The ENOG value as a useful prognostic indicator in Chinese patients with Bell's Palsy in Hong Kong was confirmed.