AAIC 2023 ABSTRACTS CLINICAL MANIFESTATIONS Abstracts

BackgroundAs the global population of older adults continues to rise, there is an urgent need to understand the expected cognitive changes in healthy aging. Despite sex-based differences in life expectancy and age-related diseases such as Alzheimer's disease, limited research has explicitly examined sex differences in aging. The objective of the current study was to answer three primary questions using longitudinal data for sample of healthy adults: 1) How does cognition change over time? 2) What are the sex differences in cognition? and 3) What are the sex differences in rates of cognitive change over time? MethodLongitudinal data from the healthy control group of the Parkinson's Progression Markers Initiative was used to examine cognitive changes in healthy adult males (n = 125, mean age = 61.61, SD = 10.97) and females (n = 68, mean age = 59.44, SD = 11.56). Participants underwent annual neuropsychological testing for up to five years. A series of 2-level linear mixed models estimated within-person change in cognition over time (i.e., level-1) and between-group differences in longitudinal change trajectories as predicted by sex (i.e., level 2). Each neuropsychological measure was modeled separately as a single outcome variable, for a total of seven models. ResultStability in neuropsychological scores was seen over five years. At baseline, males scored higher on the Benton Judgement of Line Orientation Test, while females scored higher on the Symbol Digit Modalities Test, the Semantic Fluency Test, and the Hopkins Verbal Learning Test-Revised. Rates of cognitive change over time did not significantly differ by sex. Higher age and lower education at baseline predicted lower neuropsychological scores. ConclusionStability in cognition was found across five years in a sample healthy control participants from a large multi-site longitudinal study. Sex differences in cognition were found in several domains, including visuospatial ability, processing speed, verbal fluency, and verbal memory. However, rates of cognitive change over time did not significantly differ by sex. Higher age and lower education were predictive of lower cognitive functioning. Great intraindividual variability in cognitive trajectories was observed. Future research should continue to examine factors that predict individual trajectories of aging in healthy individuals.