Cross-cultural equivalence and evaluation of psychometric properties of voice handicap index into Persian.

Quality of life is one of the important aspects in the assessment of health and treatment data output. The purpose of this study was to adapt and determine reliability and validity of Voice Handicap Index (VHI) in Persian. The subjects were 80 patients with voice disorders and 80 volunteers without any voice disorders as a control group. All subjects filled in the Persian version of VHI. The test was repeated 2 weeks later. The reliability and validity were studied. All items had significant discrimination coefficient. The internal consistency and reliability of test and retest in VHI total score and three subtests were achieved. It seems that the Persian version of VHI is a valid and reliable questionnaire, which voice therapists may use for completing their evaluation for patients with voice disorders, and it gives more information about the nature of voice disorder to specialists.