A - 50 Examining NfL as a Moderator for APOE Status and Cognitive Dispersion.

Abstract

Cognitive intra-individual variability (IIV) dispersion, a measure of variability across multiple tasks, has been associated with cognitive decline. Neurofilament light chain protein (NfL) is a known biomarker for several neurodegenerative diseases and reflects disease severity. Apolipoprotein E (APOE ε4) gene is a biomarker known to increase the risk of dementia. This study aimed to examine the relationship between cognitive IIV and biomarkers with established relationships to dementia in a diverse older sample. Data was collected as a part of the Health and Aging Brain Study: Health Disparities (HABS-HD) study, a project examining biomarkers of Alzheimer's disease across diverse populations within a health disparities framework. IIV on neuropsychological test performance was calculated for each participant (n = 1621) as the coefficient of variation (CoV). A moderation test employing Hayes' process model was run, with APOE ε4 status as the predictor, IIV as the dependent variable, and NfL as a moderator. Hayes PROCESS model 1 evaluated the moderating role of APOE ε4 status on the relationships between NfL and IIV. There was a significant interaction found between NfL and APOE ε4 status, (p = 0.0005). The total model was significant but only accounted for approximately 0.74% of the variance in IIV (R^2 = 0.007, SE = 0.001, p < 0.001). A larger moderation effect was found in APOE ε4 carriers. We found a small effect for biomarkers predicting cognitive IIV. The effect of NfL on IIV was partially moderated by APOE ε4 status. This relation between IIV and biomarkers should be examined in samples with greater symptom severity.