Functional disabilities profile of chinese elderly people with Alzheimer's disease - a validation study on the chinese version of the disability assessment for dementia

Abstract

This study aimed to determine the validity and applicability of the Chinese version of the Disability Assessment for Dementia (CDAD) in the Chinese elderly population. The original English version was translated and modified to a 47-item scale to suit the societal and cultural background of the Chinese population. The CDAD was administered to 169 community-residing Chinese elderly people with Alzheimer's disease (AD) and demonstrated high internal consistency (Cronbach's α = 0.91), excellent test-retest reliability (intraclass correlation, ICC = 0.99) and excellent interrater reliability (ICC = 0.98). The functional disabilities profile of the same sample was examined. The CDAD had a high negative correlation with the Global Deterioration Scale (GDS; Spearman's ρ = -0.89, p < 0.001). ANOVA and post hoc comparisons showed there were significant differences in the mean CDAD scores across different GDS stages. To study the construct validity, the CDAD was administered concurrently with several instruments. The Instrumental Activities of Daily Living subscore of the CDAD had a high correlation with the Instrumental Activities of Daily Living Scale (r = 0.94, p < 0.001), and the Activities of Daily Living subscore of the CDAD had a high correlation with the Modified Barthel Index (r = 0.82, p < 0.001). A moderate correlation (r = 0.60, p < 0.001) with the Cantonese version of the Mini Mental State Examination was also found. Analysis of the relationship with sociodemographic factors indicated that the CDAD was not correlated with gender and education, and that the correlation with age was low. The CDAD was shown to be a reliable and valid instrument in assessing the functional disabilities of community-residing elderly subjects with AD in the Chinese population.