Prognostic Impact of the 10% Electroneurography Threshold on Complete Recovery in Pediatric Bell’s Palsy: A Hazard Ratio Analysis

OBJECTIVE: To investigate the ability of the 10% electroneurography (ENoG) threshold to predict complete recovery (House-Brackmann [H-B] grade I without sequelae) in pediatric Bell's palsy. METHODS: This retrospective study included 27 pediatric patients aged 0 to 12 years with Bell's palsy who underwent ENoG between 8 days and 3 weeks after onset. All the patients received corticosteroid therapy (prednisolone ≥1 mg/kg/day), with severe cases receiving a high-dose regimen (2-4 mg/kg/day). The primary endpoint was complete recovery, defined as H-B grade I with no pathologic synkinesis or facial contracture. Recovery profiles were compared between a high-ENoG group (ENoG ≥10% residual amplitude, n=13) and a low-ENoG group (ENoG <10% residual amplitude, n=14) over a 12-month, follow-up period. RESULTS: All the patients (100%) attained at least H-B grade II. The high-ENoG group had a 100% complete recovery rate within 3 months, whereas the low-ENoG group had a 50% complete recovery rate and a significantly longer time course. Log-rank analysis demonstrated a significant difference in the recovery curve (P<0.001). Receiver operating characteristic curve analysis confirmed that the 10% threshold was optimal for predicting complete recovery (area under the curve: 0.804; 100% specificity for predicting complete recovery). Cox regression analysis identified ENoG ≥ 10% residual amplitude as the most accurate predictor of complete recovery (hazard ratio: 9.61; 95% CI: 2.64-34.89; P<0.001). CONCLUSION: While pediatric Bell's palsy had an excellent overall prognosis in terms of functional improvement (H-B grade II), the ENoG 10% threshold was the best predictor of complete recovery without permanent sequelae.