Clinical Manifestations.

Background: The Cognitive Domains and Functional Assessment Questionnaire (CDFAQ) assess cognitive and functional decline for Neurocognitive Disorders based on the DSM-5 criteria (1). It's accuracy to the Informant Questionnaire on Cognitive Decline in the Elderly - Long Version (IQCODE-LV) has been assessed (2), and was translated and validated into English. The informant version (CDFAQ-IV) assess: Complex Attention (CA), Executive Functions (EF), Learning and Memory (LM), Language (L), Perceptual-Motor (PM) and Social Cognition.

Methods: To evaluate the CDFAQ-IV's accuracy to IQCODE-LV across participant's educational levels. Both questionnaires were applied to 196 informants of older adults. Older adults were stratified by educational levels into three groups: 73 participants had low educational level (0-3 years), 71 had middle educational level (4-7 years), and 52 with high educational level (8 or more years). Accuracy assessment was made by Receiver Operating Characteristic (ROC) and cut-off values defined by Youden's J statistic. This study was approved by the ethics committee of UFMG.

Results: The low educational group had good accuracy (Area Under the Curve = 0.879) for the CDFAQ-IV total score, excellent accuracy for the EF domain (AUC = 0.907), good accuracy for LM domain (AUC = 0.822) and poor accuracies for other domains. For the middle educational group, CDFAQ-IV (AUC = 0.908) and LM domain (AUC = 0.914) showed excellent accuracies, while CA (AUC = 0.876), L (AUC = 0.832) and SC (AUC = 0.814) domains showed good accuracies. The others domains showed poor accuracies. For high educational group, LM domain (0.924) had excellent accuracy, while CDFAQ's total score (AUC = 0.894) and L domain (AUC = 0.898) showed good accuracy. Poor accuracies were found for the other domains.

Conclusions: CDFAQ's total score shows good accuracy in samples of low and high educational levels and excellent accuracy in samples with 4 to 7 years of schooling. Interestingly, the LM domain shows excellent accuracy (AUC > 0.9) in samples with higher levels of education. Brazilian older adults have lower educational levels and more heterogeneity in schooling quality compared to those from high-income nations. Assessment of psychometric properties according to education is needed, as well as more scenarios such as studies in community and clinical settings.