Reliability and validity of vocal fatigue index (VFI) in Japanese version study of patients with dysphonia and healthy young to middle-aged adults

Abstract

Objective: The purpose of this study was to examine the reliability and validity of the VFI translated into Japanese. Participants: The participants were 102 adults in six ENT clinics in Japan and 56 normal volunteers. There was no difference in male-to-female ratio between the groups with and without dysphonia. Analysis: The reliability of the VFI in the Japanese version was measured using Cronbach s alpha of internal consistency. Criterion-related validity was assessed by the extent to which the VFI in the Japanese version predicted the presence or absence of dysphonia. Results: Cronbach s alpha of the VFI in the Japanese version was 0.919 for all participants. There were significant differences between the dysphonic and non-dysphonic groups. Conclusion: The VFI in the Japanese version consistently showed reliability. The scores of the VFI in the Japanese version can predict the presence or absence of dysphonia.