Cognitive Changes with Emerging Alzheimer Disease Pathology

Amyloid deposition occurs prior to the onset of tau pathology in Alzheimer disease (AD). Researchers conducted this study aiming to identify cognitive measures associated with the earliest detectable signs of amyloid-β and tau pathology in cognitively normal adults from the Harvard Aging Brain Study. At baseline, participants were negative for amyloid deposition based on Pittsburgh compound B (PiB), defined as having Centiloid (CL) values less than 20, or were PiB positive with CL values less than 40, which is the threshold thought to be when tau proliferation begins. Tau levels were identified by ¹⁸F-flortaucipir (FTP)-PET levels in the entorhinal and inferior temporal cortices. Cognitive testing focused on episodic memory (including learn…