Cutoff scores of the cognitive abilities screening instrument, Chinese version in screening of dementia

Abstract

The purpose of this study of dementia screening was to obtain different cutoff scores of the Cognitive Abilities Screening Instrument, Chinese versions (CASI C-2.0) for subjects with different educational backgrounds. The diagnosis of dementia was based on the Diagnostic and Statistical Manual of Mental Disorders, ed 3 revised or ed 4 criteria. To diagnose Alzheimer's disease, the guidelines of the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer's Disease and Related Disorders Association was followed. The severity of dementia was determined on the Clinical Dementia Rating scale. Altogether 2,096 subjects, aged 65 years and more, were included. Of them, 1,178 were normal and 918 were demented. Their performance on CASI C-2.0 was influenced by their education and age. Gender difference on CASI C-2.0 scores was only significant in the illiterate, but not in the literate group. We recommend that the population be divided into three levels, namely those who (1) had no formal education (Edu = 0); (2) received 1-5 years of schooling (Edu = 1-5), and (3) received 6 or more years of education (Edu >/=6). The cutoff scores of CASI C-2.0 in the diagnosis of dementia in these three educational groups were as follows: Edu = 0: 49/50 (sensitivity = 0.83; specificity = 0.85); Edu = 1-5: 67/68 (sensitivity = 0.83; specificity = 0.91), and Edu >/=6: 79/80 (sensitivity = 0.89; specificity = 0.90).