Differences in the measurement of cognition for the assessment of dementia across geographic contexts: Recommendations for cross-national research

Introduction: Most cognitive assessments have been developed in high-income countries but are used in diverse contexts. Differences in culture and context may affect the performance of cognitive items. Methods: We used the Harmonized Cognitive Assessment Protocol (HCAP) surveys in the United States, Mexico, India, England, and South Africa (combined N = 11,364) to quantify associations across countries between cognitive items and cognitive impairment status using age- and sex-adjusted logistic regression. Results: Associations were stronger in the United States (median odds ratio [OR] across items = 0.17) and England (median OR = 0.19), compared to South Africa (median OR = 0.23), India (median OR = 0.29), and Mexico (median OR = 0.28). Items assessing memory (e.g., delayed recall tasks) had the most consistent associations of the largest magnitudes across contexts. Discussion: Transporting cognitive items among countries and cultures warrants caution. Our results can guide the design of future instruments by identifying items that performed well either in individual contexts or across the range of contexts considered. HIGHLIGHTS: Little quantitative evidence exists to guide the design of cognitive assessments in cross-national studies. The performance of cognitive items for the measurement of dementia varied across countries. Items with lower variation across countries (e.g., delayed word recall) should be used in future cross-national assessments. Across countries, there was variability in the performance of language assessments, with the exception of the animal naming task. Results can be used to design future cross-national or location-specific cognitive assessments.