Cognitive measures in the Canadian Longitudinal Study on Aging

We describe the implementation of cognitive measures within the Canadian Longitudinal Study on Aging (CLSA), a nationwide, epidemiological study of aging, and relate CLSA Tracking cohort data (n over 20,000) to previous studies using these measures.

CLSA participants (aged 45-85, n over 50,000) provided demographic, social, physical/clinical, psychological, economic, and health service utilization information relevant to health and aging through telephone interviews (Tracking cohort, n over 20,000) or in-person (i.e. Comprehensive cohort, n over 30,000) in both official languages (i.e. English, French). Cognitive measures included: the Rey Auditory Verbal Learning Test (RAVLT) - Trial 1 and five-minute delayed recall; Animal Fluency (AF), the Mental Alternation Test (MAT) (both cohorts); Controlled Oral Word Association Test, Stroop Test, Prospective Memory Test, and Choice reaction times (Comprehensive Cohort).

Performance on the RAVLT Trial 1 and AF were very similar to comparable groups studied previously; CLSA sample sizes were far larger. Within the CLSA Tracking cohort, main effects of age and language were observed for all cognitive measures except RAVLT delayed recall. Interaction effects (language × age) were observed for AF.

This preliminary examination of the CLSA Tracking cognitive measures lends support to their use in large studies of aging. The CLSA has the potential to provide the 'best' comparison data for adult Canadians generated to date and may also be applicable more broadly. Future studies examining relations among the psychological, biological, health, lifestyle, and social measures within the CLSA will make unique contributions to understanding aging.