Screening for Dementia and Cognitive Decline in Adults With Down Syndrome: A Novel Approach Using the Informant Questionnaire on Cognitive Decline in the Elderly.

ABSTRACT

OBJECTIVE: The aim was to examine the psychometric properties of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) as a diagnostic tool to screen for dementia in aging individuals with Down syndrome (DS). METHODS: This was a cross-sectional study of 92 individuals with DS 30 y or above of age) evaluated with the IQCODE. Using the informant questionnaire of the Cambridge Examination for Mental Disorders of Older People with Down's Syndrome and Others with Intellectual Disabilities, we divided the subjects into 3 diagnostic groups stable cognition; prodromal dementia; and dementia. The ability of the IQCODE to discriminate between diagnostic groups was analyzed by calculating the areas under the receiver operator characteristic curves (AUCs). RESULTS: The optimal IQCODE cutoffs were 3.14 for dementia versus stable cognition (AUC=0.993; P<0.001) and 3.11 for prodromal dementia+dementia versus stable cognition (AUC=0.975; P<0.001), with sensitivity/specificity/accuracy of 100%/96.8%/97.3%, and 93.3%/91.9%/92.4%, respectively. The IQCODE showed a weak-to-moderate correlation with cognitive performance (P<0.05). CONCLUSION: The IQCODE is a useful tool to screen for cognitive decline in individuals with DS and is suitable for use in a primary care setting.