Effect of Vocal Function Exercises on the Voice Handicap Index, Vocal Fatigue Index, and Number of Vocal Fatigue Symptoms in Bank Workers: Single-Blinded Randomized Controlled Trial

Vocal fatigue (VF) is a significant portion of occupational voice disorders. Researchers have proposed numerous therapeutic approaches to alleviate VF. However, the efficacy of vocal function exercises (VFEs) as a safe, effective, and simple method is unclear. The current study aims to investigate the effect of VFEs on occupational-related VF in Iranian bank workers. A single-blinded randomized controlled trial with four-level blocking After screening 444 workers, 43 persons with vocal fatigue (VF) were allocated between intervention and control groups. The gender of participants was considered a confounding parameter. Intervention group participants (IGP) (20 males and two females) practiced vocal function exercises (VFEs) (online training) for two weeks, while control group participants (CGP) (20 males and a female) continued their routine lifestyle. The Number of Vocal Fatigue Symptoms (NoVFS), Maximum Phonation Time (MPT), Voice Handicap Index (VHI), and Vocal Fatigue Index (VFI) at pre-intervention and post-intervention levels were gathered and compared. According to the intergroup, pre-/post-intervention differences, and intragroup analysis, the IGP experienced a significant reduction in the NoVFS (P = 0.006, P = 0.009), the mean score VHI (P:0.006, P: 0.001, P: 0.001), the total mean score of VFI (P < 0.001, P < 0.001, P < 0.001), and the first (P = 0.005, P = 0.002, P < 0.001) and second (P = 0.006, P < 0.001) factors' mean score of VFI. Additionally, there was an improvement in the MPT (P < 0.001, P < 0.001, P < 0.001) and the third factor (P = 0.01, P = 0.004, P = 0.021) mean score of VFI. Vocal function exercises can alleviate symptoms, voice handicaps, tiredness, avoidance, and physical discomfort of vocal fatigue in bank workers. Additionally, it can improve glottal (pulmonary) sufficiency and rest recovery of vocal fatigue in this group of workers.