Cross-cultural adaptation and validation of the voice-related quality of life into Persian.

The purpose of this study was to adapt and determine reliability, validity, and responsiveness of voice-related quality of life (V-RQOL) for Persian. A total of 300 patients with voice disorders participated in the study. Also, 116 people without any voice disorders volunteered to participate in the study as a control group. All participants filled in the Persian version of V-RQOL. The reliability, validity, and responsiveness were studied. Results demonstrated that the discrimination coefficient is significant for all items. The V-RQOL measure showed a strong internal consistency (Cronbach alpha coefficient = 0.88-0.91) and a good test-retest reliability (r = 0.93-0.95). Pre- and post-treatment results showed a significant responsiveness (functioning, 0.000; social-emotional, 0.001; and total, 0.000). Effect size range of 1.26-1.59 and the standardized response mean range of 1.07-1.41 were obtained for V-RQOL. It seems that the Persian version of V-RQOL is valid, reliable, and responsive to change, and this questionnaire can be used for completing voice evaluation for patients with dysphonia.