High-power Laser Therapy for Bell's Palsy Recovery: Opening a New Window; a Randomized Clinical Trial

Abstract

Background: Bell's palsy is the most prevalent cause of unilateral facial paralysis and affects facial function and aesthetics. Numerous physical therapy approaches have been used to promote recovery from this condition. Laser therapy is a noninvasive modality used for several peripheral neurological disorders; however, its utility in Bell's palsy has not been well studied. Objectives: This study aimed to evaluate high-power laser therapy for managing Bell's palsy. Methods: This randomized clinical trial included 30 patients who developed Bell's palsy 1 - 12 months before the intervention and did not respond to conventional therapies. Participants were randomly assigned to exercise therapy alone, consisting of facial massage and facial expression exercises, or to exercise therapy combined with high-power laser therapy, delivered in 3 weekly sessions for 4 weeks, using a randomization table at Isfahan University of Medical Sciences in 2023 - 2024. The House-Brackmann Scale (HBS) score and severity index were assessed at baseline and within 6 weeks after the intervention. The severity index was defined as the ratio of the compound muscle action potential (CMAP) amplitude on the affected side to that on the normal side, as measured by an electrodiagnostic study. Data were analyzed using SPSS version 20 with the chi-square test, independent t-test, Mann-Whitney U test, and Wilcoxon test. P < 0.05 was considered statistically significant. Results: Baseline assessments showed no differences between the groups in the severity index (P = 0.345) or HBS score (P = 0.486). In the intervention group, the severity index changed from 0.53 [0.20, 0.64] at baseline to 0.71 [0.46, 0.85] within 6 weeks (P < 0.001). In the control group, it changed from 0.26 [0.16, 0.54] to 0.31 [0.20, 0.58] (P = 0.002). The HBS score in the intervention group changed from 3 [2, 3] to 2 [2, 2] (P = 0.001), whereas in the control group, it changed from 3 [2, 3] to 3 [2, 3] (P = 0.014). Compared with exercise therapy alone, combination therapy was associated with a significantly higher severity index (0.71 [0.46, 0.85] in the intervention group vs 0.31 [0.20, 0.58] in the control group; P = 0.013) and a lower HBS score (2 [2, 2] in the intervention group vs 3 [2, 3] in the control group; P = 0.013). Conclusions: Based on the findings of this study, high-power laser therapy combined with facial massage and exercise may significantly promote facial nerve rehabilitation after Bell's palsy.