Ahmad Reza Khatoonabadi - Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
Hassan Khoramshahi - Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran; Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
Seyyedeh Maryam Khoddami - Department of Speech Therapy, School of Rehabilitation, Tehran University of Medical Sciences, Tehran, Iran.
Peyman Dabirmoghaddam - Otorhinolaryngology Research Center, Tehran University of Medical Sciences, Tehran, Iran.

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 ofvoice 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 ofvoice therapy among included patients. Paired t-test, size of the standardized effect (ESI),and mean standardized response (ESII) were used to analyze effectiveness of the target voice therapy.   Results: The findings of this study indicate astatistically significant improvement after the voice therapy protocol (P<0.05; t> 1.96). Results of ESI and ESII 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.

Muscle tension dysphonia, Voice handicap index, Vocal mass lesions, Voice therapy