Psychometric properties of the Rowland Universal Dementia Assessment Scale – Peruvian Version among Indigenous Amazonian communities

Abstract Cognitive screening tools are rarely validated for Indigenous populations of Latin America, a barrier to early dementia detection. We culturally adapted and evaluated the psychometric performance of the Peruvian version of the Rowland Universal Dementia Assessment Scale (RUDAS-PE) for Shawi Indigenous Amazonian communities. We included 434 adults aged ≥50 years who completed the RUDAS-PE. Cognitive interviews and community feedback revealed cultural mismatches, particularly in visuoconstruction tasks, requiring linguistic and contextual item modifications. The original 6-item structure showed poor fit, while a 5-item version demonstrated strong unidimensionality and improved model fit (confirmatory factor analysis, comparative fit index = 0.97; Root Mean Square Error of Approximation = 0.06). Item response analyses confirmed high measurement precision at low-moderate educational levels and identified severe floor effects in visuoconstruction. Culturally-valid adaptations of brief cognitive tools, particularly the visuoconstruction domain, are essential to avoid diagnostic bias in Indigenous populations. Our findings provide a scalable framework for adaptation of cognitive screening for Indigenous communities.