The IQCODE: an alternative screening test for dementia for low educated Thai elderly.

OBJECTIVE: To explore an alternative method of screening for dementia in Thai elderly people who have a low educational level. The Informant Questionnaire on Cognitive Decline in the elderly (IQCODE) is used as the screening test.

MATERIAL AND METHOD: A community based population of elderly subjects in Bangkok including 87 normal subjects and 73 demented elderly people were studied. Their ages ranged from 52 to 85 years old. The majority of the elderly people had had four years or less of primary-education. Dementia was diagnosed independently by DSM IV criteria. A short form of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), a short form, was administered to informants of the elderly by trained medical personnel. The Thai Mini Mental State Examination (TMSE) was also administered to these subjects and compared with the IQCODE. SPSS 9.0 was used for statistical analysis.

RESULTS: The IQCODE showed a negative correlation with the TMSE (n=160, r=-0.679, p<0.001). The area under the receiver operating characteristic curve (ROC) of the IQCODE was larger than that of TMSE (0.928 vs 0.814). On logistic regression analysis, there were only three questions that contributed to the diagnosis that showed statistical significance. These questions are remembering what day and month it is, learning how to use a new gadget and handling other everyday arithmetic problems. Applying the new formula (z-score), these three questions showed a sensitivity of 84.90 per cent, and a specificity of 92 per cent for the diagnosis of dementia.

CONCLUSION: Informants' perceptions of cognitive impairment of the elderly can be reliably applied as a screening instrument for dementia in the Thai population with a variety of educational levels. A short form of the IQCODE using selected questions can be administered with good diagnostic sensitivity and specificity.