The Japanese version of the Dizziness Handicap Inventory as an index of treatment success: Exploratory factor analysis

Conclusion: The Japanese version of the Dizziness Handicap Inventory (DHI) is a reliable, comprehensively validated, and clinically useful tool to measure self-perceived handicap associated with dizziness. Objectives: The DHI is a useful instrument to document the consequences of vestibular and/or balance impairment. A Japanese version of this self-assessment inventory is needed to evaluate the handicapping effects imposed by vestibular system disease in Japanese patients. The purpose of this study was to determine the internal consistency of the reliability of the Japanese version of the DHI. Methods: We recruited 176 patients between January and September 2008 from the outpatients of the Department of Otolaryngology, Hino Municipal Hospital, Japan. The DHI was translated into Japanese, and the test was independently completed by each subject. We used principal component analysis to evaluate the different dimensions of the DHI. The internal consistency of the retained factors was investigated by estimating Cronbach's alpha coefficients and corrected item-total correlations. Results: Cronbach's coefficients for internal consistency were high for the total scale (0.93) and good for the subscales: functional subscale (0.87), physical subscale (0.82), and emotional subscale (0.85). The correlation matrix demonstrated that the variables were suited for factor analysis. The determinant was 1.26E(-6), which is slightly under the recommended value. Bartlett's test was highly significant (p < 0.0001), and the Kaiser-Meyer-Olkin measure of sampling adequacy was 0.91.