Cross-cultural adaptation and validation of the voice handicap index into Italian

Objectives. To evaluate the internal consistency, reliability, and clinical validity of the Italian version of the Voice Handicap Index (VHI). Study Design. Cross-sectional survey study was carried out. Methods. One hundred and seventy-five patients with voice disorders, divided in four groups according to the etiology of the disease (neurogenic, structural, functional, and inflammatory), and 84 asymptomatic subjects were included in the study. Internal consistency was analyzed through Cronbach alpha coefficient. For the VHI test-retest reliability analysis, the Italian VHI was filled twice by 56 patients and 56 control subjects. The test-retest reliability was assessed through the Pearson correlation test. For the clinical validity assessment, the scores obtained in the pathological group were compared with those found in asymptomatic individuals through the Kruskal-Wallis test. Also, the correlation between VHI and the grade of voice disorder was assessed. Finally, the effect of age and gender on overall VHI and its three subscales was analyzed. Results. Optimal internal consistency was found (alpha = 0.93); the test-retest reliability in both groups was high (r > 0.86). Nonparametric Kruskal-Wallis analysis of variance for the overall VHI score and its three domains revealed a significant main effect for group (P = 0.000). The control group scored significantly lower than the four groups of voice-disordered patients. The overall VHI score positively correlated with the grade of voice disorder (r = 0.43). In the voice-disorder group, age and gender were not correlated to the overall VHI score and to their three domains. Conclusion. The Italian VHI is highly reproducible, and exhibits excellent clinical validity.