Linking cognitive variability and Alzheimer's disease biomarkers by neurocognitive status
Abstract INTRODUCTION This study aimed to assess intra‐individual cognitive variability (IICV) in relation to Alzheimer's disease (AD) biomarkers. METHODS The National Alzheimer's Coordinating Center sample (n = 879), aged 50+ with a complete neuropsychological evaluation and AD biomarker data available (64% cognitively intact; 36% cognitively impaired). Moderated regression models using AD biomarkers, neurocognitive status, and interaction effects predicted IICV. AD biomarkers included cerebrospinal fluid (CSF) measures of Aβ1‐42, phosphorylated tau 181 (p‐Tau181), total tau (t‐Tau), and amyloid positron emission tomography. RESULTS Increased AD biomarker burden was associated with increased IICV among cognitively impaired individuals (correlational strength ranging from 0.149 to 0.460) but not among the cognitively intact group. DISCUSSION Increases in measures of amyloid, soluble tau, and neurodegeneration are associated with increased IICV among cognitively impaired older adults. The findings underscore the potential of IICV as a sensitive outcome measure. Future studies should replicate findings longitudinally and in more diverse samples.