Role of tau deposition in early cognitive decline in Down syndrome.

ABSTRACT

Introduction: Drawing on the amyloid/tau/neurodegeneration (AT[N]) model, the study examined whether the tau positron emission tomography (PET) biomarker [18F]AV-1451 was associated with episodic memory problems beyond what was predicted by the amyloid beta (Aß) PET in Down syndrome (DS). Methods: Data from 123 non-demented adults with DS (M  = 47 years, standard deviation = 6.34) were analyzed. The Cued Recall Test assessed episodic memory. Tau PET standardized update value ratio (SUVR) was assessed across Braak regions as continuous and binary (high tau [TH] vs. low tau [TL]) variable. Global PET Aß SUVR was assessed as binary variable (Aß- vs. Aß+). Results: In models adjusting for controls, tau SUVR was negatively associated with episodic memory performance in the Aß+ but not Aß- group. The Aß+/TH group evidenced significantly worse episodic memory than the Aß+/TL group. Discussion: Similar to late-onset and autosomal dominant Alzheimer's disease (AD), high tau was an indicator of early prodromal AD in DS.