THE INFORMANT QUESTIONNAIRE ON COGNITIVE DECLINE IN THE ELDERLY (IQCODE) AS A SCREENING TOOL FOR DEMENTIA FOR A PREDOMINANTLY ILLITERATE CHINESE POPULATION

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCOD E) provides ratings of an individual's changes in everyday cognitive f unctions during the previous 10 years. Original studies conducted in A ustralia showed that its score was not influenced by the subjects' edu cational backgrounds and that it performed at least as well as the Min i-Mental State Examination (MMSE) as a screening instrument for dement ia. The subjects of the present study were Chinese and included 399 co mmunity residents and 61 dementia patients. Their ages ranged from 50 to 92 years; their education levels ranged from 0 to 19 years, and 63% of them had never attended school. We administered the IQCODE to info rmants and the Cognitive Abilities Screening Instrument (CASI), from w hich a CASI-estimated score of the MMSE (MMSE-CE) can be obtained, to the subjects. The diagnosis of dementia was made independently by phys icians according to the DSM-III-R criteria based on semistructured int erview and testing, neurologic examination, and standardized assessmen ts of cerebral vascular disease, Parkinson's disease, and depression. The Chinese IQCODE showed no association with the subjects' education level or gender, low association with their age, and moderately high a ssociation with their MMSE-CE score. The area under the receiver opera ting characteristic curve of the IQCODE was significantly larger than that of the MMSE-CE for the whole group and for the subgroup with 1 to 19 years of education but not for the subgroup with 0 years of educat ion. Nine of the 26 items of the IQCODE could be deleted without appre ciable reduction in sensitivity and specificity. The IQCODE (1) can be shortened to 17 items, (2) had good cross-cultural applicability, and (3) was better than the MMSE-CE as a screening tool for dementia in a population with large variation in educational backgrounds.