Cognitive trajectories among English- and Spanish-test-takers in the NACC

Cognitive assessments were traditionally developed using English-speaking populations, creating a potential disadvantage and misrepresentation for non-English speakers. We aimed to determine whether English- and Spanish-test-takers have similar or different cognitive trajectories.

Participants included 931 Hispanic/Latino adults from the National Alzheimer's Coordinating Center. Using mixed-effects regression analyses, we examined baseline differences and longitudinal changes in memory, attention/working memory, executive functioning, and language between Spanish- and English-test-takers. Models controlled for age at baseline, education, sex, Hispanic/Latino heritage, and cognitive status.

English-test-takers performed significantly better than Spanish-test-takers across all domains at baseline. No differences in cognitive trajectories were detected, except for attention/working memory, in which Spanish-test-takers declined at a slower rate than English-test-takers.

Despite baseline differences, both groups exhibited largely similar cognitive aging trajectories. These findings suggest that cross-sectional differences may reflect measurement bias rather than differences in cognitive aging and an underestimation of cognitive abilities among Spanish speakers.

Baseline disparities in cognition were observed across all domains, except for language, with Spanish-test-takers scoring significantly lower than English-test-takers. Despite baseline differences, rates of cognitive decline were largely similar across language groups, suggesting potential measurement bias rather than differences in cognitive aging. Spanish-test-takers showed greater maintenance in attention over time, pointing to possible benefits from repeated testing or cultural factors that warrant further investigation.