The subscales and short forms of the dizziness handicap inventory: are they useful for comparison of the patient groups?

ABSTRACT

PURPOSE: Dizziness Handicap Inventory (DHI) is one of the most frequently used surveys for vertigo. The aim of the study was re-analyze the consistency of subscales and correlation between original and different short forms. METHOD: The data of 2111 patients were analyzed. Original three subscales, screening form of DHI and short form of DHI were evaluated. The suitability of the data set for factor analysis and factor structure was analyzed with Kaiser-Meyer-Olkin (KMO) coefficient, Bartlett's Sphericity Test, and Varimax method. Pearson correlation analysis was performed. RESULTS: Factor analysis showed that two factor solutions are more prominent in our data. The factors proposed in different studies are not in harmony with each other. There is high correlation between the original and screening and short forms of DHI. CONCLUSIONS: This study indicated that the factor structure of the scale was not consistent. It is not advised to use subscale scores for comparison especially in international level. Therefore, total score should be used rather than the scores of the subscales. Using DHI screening form instead of original 25 questions is more convenient, because it is highly correlated with the original one and has fewer questions. Implications for rehabilitation Factor structure of the DHI is not consistent enough for comparison of the international studies. Total score of DHI is reliable. Using the screening version of DHI is better, because it is highly correlated with the original form and has fewer questions (10 questions).