Patient-Based Assessment of Effectiveness of Voice Therapy in Vocal Mass Lesions with Secondary Muscle Tension Dysphonia

INTRODUCTION: Use of patient-based voice assessment scales is an appropriate method that is frequently used to demonstrate effectiveness of voice therapy. This study was aimed at determining the effectiveness of voice therapy among patients with secondary muscle tension dysphonia (MTD) and vocal mass lesions. MATERIALS AND METHODS: The study design was prospective, with within-participant repeated measures. Thirty-three patients with secondary MTD and vocal mass lesions participated in the study, selected on the basis of voice history, laryngeal palpation, and videostroboscopy examination. An experienced otolaryngologist and one experienced speech language pathologist undertook the diagnostic process. Voice therapy included both direct and indirect techniques and lasted approximately 2 months for all included patients. The voice handicap index (VHI) was used to evaluate the effectiveness of voice therapy among included patients. Paired t-test, size of the standardized effect (ES(I)), and mean standardized response (ES(II)) were used to analyze effectiveness of the target voice therapy. RESULTS: The findings of this study indicate a statistically significant improvement after the voice therapy protocol (P<0.05; t>1.96). Results of ES(I) and ES(II )demonstrate that the VHI scale is sufficiently responsive to detect voice therapy change (ES>0.8). CONCLUSION: This study recommends a combination of direct and indirect voice therapy in the vocal rehabilitation of patients with secondary MTD and vocal mass lesions. Furthormore, we recommend use of the VHI scale to show voice therapy changes for both clinical and research purposes.