Adaptation and validation of the Voice Handicap Index in Latvian.

OBJECTIVES: To establish psychometric indicators of the Voice Handicap Index (VHI) (Latvian version) and their relationship to the psychometric indicators of the original items.

STUDY DESIGN: Parallel group design.

METHODS: The VHI was translated and adapted to Latvian. The translated version of the VHI (Lat-VHI) was completed by 54 patients with voice disorders and by 73 subjects without voice disorders forming the control group. A test-retest group included 54 subjects without voice problems, able to complete the questionnaire twice. The test-retest stability, internal consistency of items of the Lat-VHI, and content and convergent validity of the Latvian version of the VHI were analyzed.

RESULTS: The interclass correlation coefficient ratio of all scales indicated statistically significant (P<0.001) test-retest reliability for the Lat-VHI. High internal consistency was observed among the Lat-VHI total scale (α=.96), functional (α=.92), physical (α=.86), and emotional scale (α=.91) in the patient group. The Pearson moment correlation coefficient indicates a high correlation among the Lat-VHI total scale and subscales (r>0.94), as well as a high correlation among subscales (r>0.81) in the patient group. Convergent validity of the Lat-VHI was determined by comparing the Lat-VHI results with the Voice Disorder Severity scale results. Statistically significant correlation (r=0.78, P<0.001) was discovered in the patient group.

CONCLUSIONS: The Latvian version of the VHI is a psychometrically validated instrument whose indicators correspond to the psychometric indicators of the original sample.