Predicting cognitive decline: Which is more useful, baseline amyloid levels or longitudinal change?

The use of biomarkers for the early detection of Alzheimer's disease (AD) is crucial for developing potential therapeutic treatments. Positron Emission Tomography (PET) is a well-established tool used to detect beta-amyloid (A beta) plaques in the brain. Previous studies have shown that cross-sectional biomarkers can predict cognitive decline (Schindler et al.,2021). However, it is still unclear whether longitudinal A beta-PET may have additional value for predicting time to cognitive impairment in AD. The current study aims to evaluate the ability of baseline-versus longitudinal rate of change in-11C-Pittsburgh compound B (PiB) A beta-PET to predict cognitive decline. A cohort of 153 participants who previously underwent PiB-PET scans and comprehensive clinical as-sessments were used in this study. Our analyses revealed that baseline A beta is significantly associated with the rate of change in cognitive composite scores, with cognition declining more rapidly when baseline PiB A beta levels were higher. In contrast, no signification association was identified between the rate of change in PiB-PET A beta and cognitive decline. Additionally, the ability of the rate of change in the PiB-PET measures to predict cognitive decline was significantly influenced by APOE epsilon 4 carrier status. These results suggest that a single PiB-PET scan is sufficient to predict cognitive decline and that longitudinal measures of A beta accumulation do not improve the prediction of cognitive decline once someone is amyloid positive.