Validity of the 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) in individuals with Huntington disease (HD).

PURPOSE: The reliability and construct validity of the 12-item World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) were examined in individuals with Huntington disease (HD).
METHODS: We examined factor structure (confirmatory factor analysis), internal consistency reliability (Cronbach's alpha), floor and ceiling effects, convergent validity (Pearson correlations), and known-groups validity (multivariate analysis).
RESULTS: Results of a confirmatory factor analysis replicated the six-factor latent model that reflects the six separate scales within the WHODAS 2.0 (understanding and communicating; getting around; self-care; getting along with others; life activities; participation). Cronbach's alpha for the scale was 0.94, suggesting good internal consistency reliability. The WHODAS demonstrated a ceiling effect for 19.5 % of participants; there were no floor effects. There was evidence for convergent validity; the WHODAS demonstrated moderate significant correlations with other general measures of health-related quality of life (HRQOL; i.e., RAND-12, EQ5D). Multivariate analyses indicated that late-stage HD participants indicated poorer HRQOL than both early-stage HD and prodromal HD participants for all HRQOL measures.
CONCLUSIONS: Findings provide support for both the reliability and validity of the WHODAS 2.0 in individuals with HD.