Prognostic Value of Electroneuronography in Severe Cases of Facial Palsy

To examine the prognostic value of electroneuronography (ENoG) in predicting functional recovery in severe cases of acute facial palsy.

Patients with severe degrees of facial palsy (initial House-Brackmann [HB] grades IV to VI) with available electrodiagnostic studies conducted 2-4 weeks after symptom onset were reviewed retrospectively. The patients were categorized into "good recovery" and "poor recovery" groups, with the former showing mild to no dysfunction (HB I to III) and the latter exhibiting moderate to severe dysfunction (HB IV to VI) on follow-up evaluation, 2 months after onset. ENoG amplitudes in four facial muscles (frontalis, nasalis, orbicularis oculi, and orbicularis oris), as well as age, sex, affected side, disease etiology, comorbidities, and laboratory findings, were compared between the two groups.

Thirty-seven patients were included. Twenty-nine of the patients showed "good recovery," and eight showed "poor recovery" at 2 months after symptom onset. Univariate analysis yielded no significant difference in age, sex, affected side, disease etiology, comorbidities, and laboratory findings between the two groups. Preserved ENoG amplitudes (individual, average, and trimmed means) were significantly higher in the good recovery group than in the poor recovery group (p<0.005). Sex (p=0.038) and the ENoG of the nasalis muscle, acquired 2-4 weeks from symptom onset (p=0.004), showed significant differences in multivariate regression analysis.

This study suggests that the female sex and lower ENoG of the nasalis muscle, acquired 2-4 weeks from symptom onset, have negative prognostic value for the 2-month functional outcome of severe facial palsy cases.