MindCrowd-Expanded: An Online Multi-Domain Assessment of Cognitive Aging.

Background: Numerous factors, including some modifiable factors as well as demographic factors, are associated with risk for age-related cognitive impairment. Evaluating the complex interaction of these factors and their trajectories across the adult lifespan requires large sample sizes with diverse cohorts. Online research has the potential to overcome barriers to research participation and provide the statistical power required to examine individual differences in cognitive functions. Understanding the complexity of cognitive aging is critical for developing individualized interventions aimed at promoting brain and cognitive health across the lifespan.

Methods: Using a fully Web-based platform, MindCrowd-Expanded, we examined associations between age, sex, educational attainment, and cognitive performance in a large cohort of participants, aged 18-100. Tests were included from five cognitive domains - associative memory, information processing speed, and three components of executive function - inhibition, updating/working memory, and set shifting.

Results: Increased age was associated with poorer performance across all domains, especially in conditions that reflected increased task complexity. Age effects were not confined to the 6th decade and beyond but were evident across the entire age range in a relatively linear fashion. Considerable individual differences in performance were also observed, especially among older adults. We also report robust sex effects that depended on the task - males showed faster simple response times than females, while females outperformed males on associative memory. Increased level of educational attainment showed small but consistent benefits across all domains.

Conclusion: The study adds to a growing body of research demonstrating the feasibility and utility of online cognitive testing for reaching large cohorts of individuals across the adult lifespan. We report findings that mirror the existing literature on cognitive aging but also provide unique insights into the trajectory of cognitive functioning. We discuss the benefits, challenges, and future promise of Web-based testing.