Translation and Validation of the Dizziness Handicap Inventory into Thai Language.

OBJECTIVE To translate and evaluate psychometric properties of Thai version of the Dizziness Handicap Inventory (DHI-TH). STUDY DESIGN A cross-sectional study. SETTING Ambulatory. PATIENTS Fifty patients with dizziness at a vestibular clinic. MAIN OUTCOME MEASURES Translation and cross-cultural adaptation of the original English version of the DHI was performed according to published guidelines. Psychometric evaluation included internal consistency, content validity, test-retest reliability, convergent validity, discriminant ability, and responsiveness. Responsiveness was examined in 28 patients with vestibular dysfunction who received vestibular rehabilitation for 6 to 8 weeks. RESULTS There were no floor and ceiling effects. The Cronbach's alpha was good for the total score (0.87) and subscale scores (0.70 physical, 0.73 emotional, and 0.71 functional). Excellent test-retest reliability was demonstrated for the total and subscales (ICC ranged from 0.91 to 0.97, p < 0.001). The SEM was 3.50 and the MDC was 9.68. The total and subscales of DHI-TH were moderately correlated with the SF-36-TH scores (r ranged from -0.40 to -0.63). An optimal cut-off point for detection of dizziness was 21 points (98% sensitivity, 94% specificity). Responsiveness of the DHI-TH was excellent. The ES and SRM were large (1.25 and 1.59, respectively). The DHI-TH discriminated well between patients with self-perceived improved dizziness versus unchanged dizziness (AUC = 0.87). The MCID was 17 points (82.0% sensitivity, 82.0% specificity). CONCLUSION The DHI-TH demonstrated good psychometric properties for patients with dizziness. The DHI-TH is a valid and reliable instrument recommended as a measure of disability and quality of life in Thai patients with dizziness.