A Multinational Framework for Online Cognitive Impairment Diagnosis in the Caribbean American Dementia and Aging Study

Presented as part of a Gateway/HCAP consensus session at AAIC on the Caribbean American Dementia and Aging Study (CADAS). Twenty-seven clinicians from five countries (Dominican Republic, Mexico, Puerto Rico, the United States, and India) independently classified 300 older adults using CADAS survey data, applying a structured 10-question NIA-AA diagnostic algorithm through a web-based consensus platform. Each case was reviewed by at least three clinicians per country team; cases with within-country disagreement underwent moderated consensus discussion, and international consensus was defined by majority rule across all five teams.

Within-country disagreement was modest (11.9% of evaluations required moderated consensus) and was driven by disagreement over functional interference and symptom attribution rather than cognitive impairment detection. Cross-country classification rates ranged from 7.0% to 21.1%, though agreement with the international consensus was high overall (90–98%), with India as the primary exception—markedly lower endorsement of cognitive impairment from tests and informant reports yielded a sensitivity of 0.41 and specificity of 1.00 relative to the international consensus. Even within a single diagnostic framework applied to identical survey data, country-team membership is associated with meaningful threshold differences in dementia classification, with direct implications for international prevalence comparisons, cross-national diagnostic harmonization, and the calibration of survey-based classification algorithms that rely on clinical consensus as their benchmark.