Case Study - Impact of age and education on the relationship between MRI measures and cognitive performance amongst Caucasians and Hispanics
In a previous study, Dr. Mungas showed that mean differences between Hispanics and Caucasians on carefully constructed English and Spanish language neuropsychological tests can be explained by important differences in education and linguistic background; that is, ethnic differences are not present after accounting for these two environment/experience variables. Preliminary results displayed below show that relationships between neuropsychological test variables and quantitative neuroimaging are stronger after controlling for effects of education on test performance. In contrast, controlling for age either did not affect or weakened cognitive-imaging relationships. These results suggest that education has considerable effects on cognition that are independent of disease/brain pathways, while age effects are mediated through these pathways. This study shows the importance of identifying confounding effects of extraneous variables like education and also shows how these confounding effects can be isolated and eliminated.