The IQCODE Versus a Single-item Informant Measure to Discriminate Between Cognitively Intact Individuals and Individuals with Dementia or Cognitive Impairment

The present study evaluated the short Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE 2-year version) against a single item concerning informant's perception of patient's memory, as screening tools for CIND not dementia (CIND) and dementia. Data were drawn from the Aging, Demographics, and Memory Study, which is a national study that was specifically designed to provide population-based estimates of cognitive impairment and dementia in the United States. The study employed a comprehensive dementia evaluation that yielded an expert consensus-based diagnosis. Receiver-operating curves, sensitivity, specificity, negative predictive value, and positive predictive value were calculated. Both the IQCODE and the single-item instrument demonstrated only mild-to-moderate abilities to discriminate between cognitively intact individuals and individuals with CIND. Whereas the ability of the IQCODE to discriminate between cognitively intact individuals and individuals with dementia was moderate, the single-item instrument showed an adequate ability to distinguish between cognitively intact individuals and individuals with dementia. Therefore, for screening purposes, asking informants a single question concerning patients' memory is sufficient. However, if additional data concerning patients' strengths and weaknesses are needed, the IQCODE may be desirable.