The effect of education on cognitive performances and its implication for the constitution of the cognitive reserve

Some studies have suggested that people with a high educational level have a lower risk of developing dementia compared to people with a low educational level. This protective effect of education has been explained by the constitution of a cognitive reserve which might delay the cognitive and functional expression of neurodegenerative illnesses. The aim of this study is, on the one hand, to evaluate the impact of education on cognitive functioning, which is thought to support the cognitive reserve capacity and on the other, to determine the extent to which cognitive functioning is affected by other explanatory variables. The analysis was conducted on 1,022 individuals without physical or neurological disorders in the Personnes Agees Quid study. These participants were aged 66 and over and had completed a neuropsychological battery. The effect of some demographic and socioeconomic variables on cognitive performance was also analyzed. Multivariate analysis showed a significant effect of education on most neuropsychological performances, independently of the other variables, and more particularly, in the high-attention-demanding tests. A principal component analysis demonstrated that education specifically increases 2 cognitive components: controlled processes and conceptualization ability. Moreover, mental stimulation occurring after the education years, such as high-complex-activity occupations, seems to increase the controlled component. All these results suggest that the effect of education on cognitive reserve may be explained by an increase in controlled processes and conceptualization abilities. These 2 cognitive components might delay the clinical expression of neurodegenerative illnesses by maintaining global cognitive efficiency. Of these 2 components, controlled processes were also influenced by high attention-demanding occupations.