Abstract
It is a common finding that more educated older adults show higher levels of cognitive functioning and a lower risk of dementia. Cognitive reserve hypothesis additionally suggests that more educated persons are able to maintain their cognitive functioning at higher levels for longer time, resulting in initially slower decline which accelerates at higher ages. Among less educated persons however, decline is expected to be faster initially but to level off in the longer run. Longitudinal studies altogether do not support this idea, possibly because of the duration of study periods and the frequent application of growth curve models, which assume that all persons follow the same type of cognitive trajectory. We examine the existence of qualitative differences in trajectories of cognitive decline over 19 years using data on up to 592 older adults (62 to 80 years) from the Longitudinal Aging Study Amsterdam (LASA). Applying Latent Class Growth Analysis (LCGA), trajectories are identified for global cognitive functioning, processing speed, reasoning, and memory, and the effect of education on the likelihood of trajectory membership is estimated. Depending on the cognitive domain, preliminary findings show 2 to 3 trajectories that differ by level of cognitive functioning but not by shape of decline. Although education is predictive of trajectory membership, our study suggests that education is generally related to levels but not to speed or shape of cognitive decline. This finding challenges the idea that education is beneficial for normal cognitive aging beyond its effect on the levels of cognitive functioning.