Adaptation and Validation of the Voice Handicap Index (VHI)-30 into Serbian

Abstract

Objectives: To evaluate the internal consistency, test-retest reliability, and clinical validity of the Serbian version of the self-administered Voice Handicap Index (VHI)-30.

Study design: Cross-sectional study.

Methods: The English version of VHI-30 was translated into Serbian and then back-translated into English. The Serbian VHI-30 was administered to 91 patients divided into four groups according to voice pathology: structural, inflammatory, neurologic, and functional groups. The control group included 90 subjects with no voice problems. The internal consistency (Cronbach's alpha coefficient α), test-retest reliability (interclass correlation coefficient) of VHI-30, comparison of patient's and control's VHI-30 scores (Mann-Whitney U test; Kruskal-Wallis test), and correlation with overall severity of dysphonia (Spearman correlation coefficient, ρ) were calculated.

Results: In the patient group, we observed excellent internal consistency for the Serbian VHI-30 (α = 0.95) and good internal consistency for all VHI-30 subscales: physical (α = 0.88), functional (α = 0.88), and emotional (α = 0.88). The interclass correlation coefficient indicated strong test-retest reliability for patients (0.99) and controls (0.84). The mean scores of all 30 items in dysphonic participants were significantly higher than in controls (P < 0.001). Good correlation was obtained between the total scores of VHI-30 and patients' self-perceived overall severity of dysphonia (ρ = 0.748, P < 0.001). Within the patient group, the female participants displayed significantly higher VHI-30 scores than male participants (Mann-Whitney U test, P < 0.001). The VHI-30 scores showed strong correlation within different patient groups and controls (Spearman correlation coefficient: structural, 0.942; inflammatory, 0.756; neurologic, 0.888; functional, 0.982; controls, 0.882).

Conclusions: The Serbian VHI-30 is a useful and valuable tool for the evaluation of patients with vocal disorders and for making subsequent clinical decisions.

Keywords: Quality of life; Questionnaire; Serbian version; Validity; Voice Handicap Index.