Age and education effects on relationships of cognitive test scores with brain structure in demographically diverse older persons

摘要

This study examined how age and education influence the relationship between neuropsychological test scores and brain structure in demographically diverse older adults spanning the range from normal cognition to dementia. A sample of 351 African Americans, 410 Hispanics, and 458 Caucasians received neuropsychological testing; volumetric MRI measures of total brain, white matter hyperintensity, and hippocampus were available for 79 African Americans, 102 Hispanics, and 134 Caucasians. Latent variable modeling was used to examine effects of age, education, and brain volumes on test scores and determine how much variance brain volumes explained in unadjusted and age and education adjusted scores. Age adjustment resulted in weaker relationships of test scores with MRI variables and adjustment for ethnicity yielded stronger relationships. Education adjustment increased relationships with MRI in the combined sample and in Hispanics, made no difference in Caucasians, but decreased some associations in African Americans. Results suggest that demographic adjustment is beneficial when demographic variables are strongly related to test scores independent of measures of brain structure, but adjustment has negative consequences when effects of demographic characteristics are mediated by brain structure.