Cross-Cultural Adaptation and Validation of the Voice Handicap Index Into Estonian.

OBJECTIVES

This study aimed to validate the Voice Handicap Index (VHI-30) for the Estonian language and determine its psychometric properties.

STUDY

DESIGN

Cross-sectional and comparative study, combining subjective and objective methods.

METHODS

The objective data included voice recordings analyzed using the PRAAT software, which calculates the Acoustic Voice Quality Index (AVQI) to assess voice quality. Subjective data were gathered using the VHI-30 (Estonian version) (VHI-30-EST) to evaluate voice-related quality of life, and videolaryngostroboscopy was performed to examine vocal fold function in patients with dysphonia. Ten percent of the participants completed the VHI again after 2-4 weeks to assess test-retest reliability. The questionnaire's internal consistency, test-retest reliability, and clinical validity were evaluated.

RESULTS

The VHI-30-EST demonstrated excellent internal consistency, with a Cronbach's α of 0.977 in the test group and 0.893 in the control group. The test-retest reliability was strong, with an intraclass correlation coefficient of 0.968 for the total score. Validity analysis showed significant differences between the test and control groups for both VHI-30-EST and AVQI scores. Receiver operating characteristic curve analysis identified effective cut-off scores of 15.5 for VHI-30-EST and 2.8 for AVQI, with high sensitivity for both. Moderate correlations were found between VHI-30-EST scores and AVQI in the test group.

CONCLUSIONS

The VHI-30-EST demonstrated strong internal consistency, excellent test-retest reliability, and solid clinical validity. Significant differences were observed between the test and control groups for both VHI-30-EST and AVQI scores, with moderate correlations between them. Effective cut-off scores were identified for both VHI-30-EST and AVQI, showing high sensitivity in distinguishing voice disorders. These results confirm the reliability and validity of VHI-30-EST in assessing voice-related quality of life in Estonian-speaking individuals.