Cross-cultural adaptation and validation of vocal fatigue index (VFI) to Chinese language.

Objectives: This study aimed to translate the Vocal Fatigue Index (VFI) into Simplified Chinese and test its reliability and validity in mainland China. Methods: The original English version of the VFI was translated and adapted to a Simplified Chinese version (VFI -SC). Fifty-four participants with voice disorders and 21 healthy controls completed the VFI-SC. Sixteen participants with voice disorders completed it again two weeks later. Reliability, validity, and receiver operating characteristic (ROC) of the VFI-SC were analyzed. Results: The Cronbach's alpha values for the VFI factor scores were found to be 0.930 for tiredness and avoidance of voice use (factor 1), 0.878 for physical discomfort with voice use (factor 2), and 0.915 for improvement of symptoms with voice rest (factor 3). The test-retest reliability was 0.967 for all three factors. There was a significant difference between the total scores of the patient group and the control group (p < 0.01). Factor 1 and factor 2 were positively correlated with the Voice Handicap Index (VHI-30). The ROC curves showed acceptable intrinsic accuracies for factor 1 (AUC = 0.883), factor 2 (AUC = 0.901), and factor 3 (AUC = 0.800), with cutoff scores of 22, 7, and 9, respectively. Conclusions: This study provides preliminary evidence that the VFI-SC has good reliability and validity. It can be used to screen for clinical symptoms of voice fatigue in mainland China.