Validation of the Czech Version of the Voice Handicap Index.

Objective(s): The present study aims to evaluate the reliability and construct validity of the Czech version of the Voice Handicap Index (VHI-CZ) and determine the cut-off value to distinguish dysphonic patients from nondysphonic individuals.

Study Design: Prospective study, Parallel group design.

Methods: The study investigated 100 adult patients with dysphonia, divided into three groups based on the etiology of the voice problem (neurogenic, functional, and structural). Out of these, 25 patients were used for test-retest analysis, and 45 patients to determine the responsiveness to change. The control group consisted of 51 healthy subjects. All 151 individuals completed the VHI-CZ and were examined with the videolaryngostroboscopy. The internal consistency (Cronbach's alpha), the test-retest reliability (Intra-class Correlation Coefficient, ICC), and the construct validity were analyzed and the normative cut-off value was determined.

Results: The internal consistency of the VHI-CZ was excellent (Cronbach α = 0.984), and test-retest reliability was also excellent (ICC = 0.95, P < 0.001). The correlation between the self-assessed severity of the voice disorder and the VHI-CZ score was strong (Spearman's ρ = 0.877, P < 0.001). The VHI scores differences between dysphonic and nondysphonic patients were statistically significant (Mann-Whitney U test, P < 0.001). The differences among the three etiological subgroups (neurogenic, functional, and structural) were also statistically significant (Kruskal-Wallis test, P < 0.001). Moreover, the differences in the VHI-CZ total scores between pretreatment and posttreatment were statistically significant (Wilcoxon test, P < 0.001). The cut-off score of 13 points was found, by the analysis of the Receiver Operating Characteristic (ROC, Youden Index), to be most suitable for preselecting dysphonic individuals.

Conclusion: The existing VHI-CZ showed excellent reliability and construct validity. The Czech VHI is a useful and valid monitoring tool for clinicians.