Reappraisal of the Prognostic Factors of Outcome and Recovery Time in Patients with Idiopathic Bell’s Palsy: A Retrospective Single-Center Analysis

Study Objectives: This retrospective study investigated prognostic factors and recovery time in patients with Bell’s palsy after different doses and durations of oral glucocorticoid treatments. Subjects and Methods: A total of 396 patients initially diagnosed with Bell’s palsy that had visited the Department of Neurology of Chang Gung Memorial Hospital, Taoyuan, a tertiary referral medical center in Taiwan, between January 2014 and December 2018 were included. Medical records, facial electroneurography (fENoG), and blink reflex (BR) tests were reviewed and analyzed. A favorable outcome was defined as patients who improved to grade ≤ II, and an unfavorable outcome was defined as patients who improved to grade ≥ III in 6 months according to the House–Brackmann (HB) grading system. Results: The rate of favorable outcomes was 89.4% (354 of 396 patients) at the 6-month follow-up. A favorable outcome (HB less than grade II) was associated with a delayed BR (odds ratio, OR, 5.38; 95% CI, 1.82 to 15.90) and fENoG values (the lesion side/the healthy side) over 33% (OR, 6.67; 95% CI, 3.02 to 14.71). The recovery time was significantly shorter for those with a delayed BR than for those with an absent BR and shorter for those with good fENoG values (>33%) than for those with poor values (≤33%). However, treatment without or with different doses and durations of oral glucocorticoid did not influence the final outcome or recovery time in this study. Conclusions: The fENoG and BR tests were significant and highly valuable examinations for predicting the final outcome. Moreover, age younger than 60 years, a delayed BR, and fENoG values > 33% were associated with shorter recovery times.