Subjective cognitive decline is indicative of accumulation of early tauopathy in the medial temporal lobe, specifically in the entorhinal cortex, and to a lesser extent, elevated global levels of neocortical β-amyloid (Aβ), according to a recent study. These findings suggest multiple underlying pathways that motivate subjective cognitive decline (SCD) that do not necessarily interact to influence SCD endorsement. This imaging sub-study of the Harvard Aging Brain Study included 133 clinically healthy older participants (Clinical Dementia Rating Scale global scores of 0) who underwent cross-sectional flortaucipir F 18 positron emission tomography (FTP-PET) imaging for tau and Pittsburgh compound B carbon 11–labeled PET (PiB-PET) imaging for Aβ. Researchers found:

• 39 participants (29.3%) exhibited a high Aβ burden.
• Greater SCD was associated with increasing entorhinal cortical tau burden (β = 0.35) and Aβ burden (β = 0.24), but not inferior temporal tau burden (β = 0.10).
• This association between entorhinal cortical tau burden and SCD was largely unchanged after accounting for Aβ burden (β = 0.36), and no interaction influenced SCD (β = −0.36).