The comparison between vocal facilitating techniques, manual circumlaryngeal therapy, and combined voice therapy in teachers with muscle tension dysphonia: a randomized clinical trial.

Abstract

Although voice therapy (VT) has been known effective in muscle tension dysphonia (MTD), it is not obviously clear which VT approach is more effective. This study aimed to compare the effectiveness of Vocal Facilitating Techniques (VFTs), Manual Circumlaryngeal Therapy (MCT), and combined VT in teachers with MTD. This study was a double-blind parallel randomized clinical trial. Thirty elementary female teachers with MTD were divided into three treatment groups including VFTs; MCT, and combined VT. In addition, vocal hygiene was presented to all groups. All participants received 10 individual 45-min sessions of VT twice a week. The effectiveness was assessed using Vocal Tract Discomfort (VTD) scale and Dysphonia Severity Index (DSI) before and after treatment and improvement measurement was calculated. The participants and data analyzer were blinded to the type of VT. All groups showed significantly better results on the subscales of VTD scale and DSI score after VT (p ≤ 0.001; η2 ≥ 0.90). There was a significant difference between the three groups on the results of VTD scale and DSI score (p ≤ 0.05). The improvement measurement on the VTD severity subscale and DSI score following the combined VT was the greatest compared with other groups (η2 = 0.99 and 0.98, respectively). The significant interactive effect of treatment and time was observed on the VTD severity subscale and DSI score (p < 0.05; η2 ≥ 0.56). This study showed that the VFTs, MCT, and combined VT were effective for MTD teachers, and the combined VT is the most effective one. It seems the combination of different approaches is recommended for the VT of MTD patients.