The Alzheimer's Disease Assessment Scale: findings from a low-education population

Abstract

We constructed a Chinese version of the cognitive component of the Alzheimer's Disease Assessment Scale (ADAS-Cog). In order to accommodate illiteracy, the Chinese version used pictures instead of words for assessing recall and recognition. The Chinese ADAS-Cog was administered to 125 individuals with no dementia, 127 with questionable dementia, and 77 with Alzheimer's disease (AD). Their age range was 51-92 years and their education range was 0-20 years. The Chinese ADAS-Cog had high internal consistency (Cronbach's alpha = 0.87) and very high interrater reliability (intraclass correlation coefficient, or ICC, = 0.99) and test-retest reliability (ICC = 0.96). It had high correlations with scores on the Clinical Dementia Rating Scale (Pearson's r = 0.85), the Cognitive Abilities Screening Instrument (CASI, Pearson's r = -0.88), and CASI-estimated scores on the Mini-Mental State Examination (Pearson's r = -0.85). Performance on the Chinese ADAS-Cog was uninfluenced by age or gender, nor by education level except within the low education range of 0-6 years. Its memory items were best for early detection of dementia; its language items were best for monitoring the progression of dementia. This study found that the Chinese ADAS-Cog is a good instrument for use with Chinese AD patients.