Linear and nonlinear relationships between cognitive subdomains of ability discrepancy and Alzheimer’s disease biomarkers.

Objective null Substantial research indicates that fluid and crystallized abilities are highly correlated throughout the adult life span. However, recent proposals suggest that a large discrepancy between these two abilities, defined as crystallized performance minus fluid performance, indicates heightened risk for Alzheimer's disease (AD). null Method null In 266 cognitively healthy older adults, the present study tested linear and quadratic...