Predicting recovery in Bell’s palsy: the impact of early rehabilitation and prognostic indicators

Abstract

Purpose: To evaluate functional outcomes and prognostic factors in Bell’s palsy (BP) patients treated with medical therapy and facial neuromuscular retraining (fNMR), with a focus on the timing of rehabilitation. Methods: Ninety-four patients with FP treated at our center were retrospectively analyzed. Patients were stratified by time to rehabilitation (TTR): Early Rehabilitation (≤ 60 days), who accessed our unit directly, and Late Rehabilitation (> 60 days), who had first received other treatments or rehabilitation not including fNMR elsewhere. Outcomes included House–Brackmann (HB) grade, Sunnybrook score, synkinesis, and time to recovery onset (TTRO). Complete recovery was defined as HB I at 12 months. Results: At 12 months, 60 patients (63.8%) achieved complete recovery, while 34 (36.2%) did not. Median TTR was 23 days [IQR 16–68], and median TTRO was 48 days [30–113]. Early Rehabilitation was associated with significantly better outcomes at 6 and 12 months, with higher Sunnybrook scores and lower HB grades (all p < 0.001), and with faster TTRO. In univariable analyses, cardiovascular and metabolic comorbidities were associated with poorer recovery. Longer TTR, delayed TTRO, higher baseline HB, lower baseline Sunnybrook, synkinesis, and previous rehabilitation were predictors of worse outcomes. At multivariable logistic regression, TTRO emerged as the only independent predictor of complete recovery (p = 0.017). Conclusions: Early initiation of standardized fNMR was associated with more favorable functional recovery, while delayed rehabilitation and systemic comorbidities predicted worse outcomes. Recovery beyond 12 months was exceptional, confirming the first year as the critical window for meaningful nerve regeneration.