Optimal cutoff, cognitive impairment diagnostic performance, reliability and concurrent validity of the Ascertaining Dementia 8 (AD8) questionnaire among Latinos

The Ascertaining Dementia 8 (AD8) is a brief informant- or self-administered questionnaire designed to screen for cognitive impairment, offering several advantages over performance-based screening tests. We analyzed cross-sectional data from a non-probabilistic sample of English- and Spanish-speaking Latinos who were either cognitively unimpaired or had a research diagnosis of mild cognitive impairment or dementia. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analysis, and the Youden Index was used to determine the optimal cutoff score. Internal consistency was tested with the Kuder-Richardson Formula 20, and concurrent validity with correlations to the Clinical Dementia Rating scale, Mini-Mental State Exam, and Montreal Cognitive Assessment scores. Among 46 participants, the optimal cutoff was 3 or higher for the total sample and in both language groups. At this threshold, the AD8 showed a sensitivity of 73.7% and specificity of 85.2%, with an area under the curve of 0.843. The AD8 achieved good internal consistency of 0.872 and demonstrated correlations in the expected directions with the cognitive impairment measures. The Spanish version generally outperformed the English version. The AD8 questionnaire has adequate psychometric properties and diagnostic performance among US Latinos. To our knowledge, this is the first manuscript to validate the AD8 among US Latinos. These findings support its use in healthcare settings and its applicability for multiple research purposes.