Screening of dementia in community-dwelling elderly through informant report.

Screening tools for cognitive decline still have low accuracy for dementia, mainly in cases of mild dementia. All of them are affected by factors such as age, sex, educational level, sensory deficits and several mental disorders. The information provided by a proxy close to the patient has been used during recent years in dementia diagnosis. Therefore, new questionnaires, which use standardized information from relatives, have been developed. The aim of this study was to validate a Spanish version (S-IQCODE) of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), a dementia screening questionnaire in Spanish population-based samples. A validity study of the screening tool was carried out in two population-based samples of community-dwelling elderly with different sociodemographic characteristics (urban and rural samples). Dementia diagnosis was performed by neurologists according to DSM-III-R criteria. The S-IQCODE showed a higher accuracy than the MMSE in both samples: sensitivity of 82% and 83% vs 73% and 83%, specificity of 90% and 83% vs 78% and 74%, accuracy of 89% and 83% vs 77% and 75%. Moreover, while the S-IQCODE did not have associations with any extraneous factors, the MMSE showed significant correlations with age (-0.51), educational level (0.62), mental health (-0.40), premorbid intelligence (0.67) and intellectual level (0.75). The results obtained with the S-IQCODE show that it could possibly be applied in screening for dementia in community-dwelling elderly.