Cross-Cultural Adaptation and Validation of the Vocal Fatigue Index (VFI) into Persian

Background and objective:Vocal fatigue(VF) is a complex multifaceted clinical phenomenon and one of the most common symptoms of a voice disorders that frequently has been used in the research and clinical practice. The aim of the present study was to adapt and determine reliability and validity of Persian Version of Vocal Fatigue Index (VFI) to help identify persons with vocal fatigue and characterize their complaints.Materials and Methods:In this descriptive-analytical study, psychometric analyses were performed on the translated Persian version of theVFI. TheVFI questionnaire was completed by 80subjects with voice disorders and by 50volunteers without any voice disorders. All participants filled in the Persian version of VFI. The test was repeated 1 weeks later. The reliability and validity were evaluated.Findings:Results of the study demonstrated that the discrimination coefficient is significant for all items. The VFI measure showed a strong internal consistency (Cronbach alpha coefficient= 0.83-0.95) and a good test-retest reliability (r = 0.75-0.89). Also for clinical validity, a significant difference was found between the control and the patient group for total score and three factors of the VFI.Conclusion: The Persian version of the VFI is considered to be a valid and reliable questionnaire for identify persons with probable VF and voice therapists can be used it for completing voice evaluation.

Keywords:

Vocal fatigue , Reliability , Validity , Sensitivity