Objective subtle cognitive decline and plasma phosphorylated tau181: Early markers of Alzheimer's disease‐related declines
Kelsey R. Thomas, Katherine J. Bangen, Emily C. Edmonds, Alexandra J. Weigand, Kayla S. Walker, Mark W. Bondi, Douglas Galasko, for the Alzheimer's Disease Neuroimaging Initiative
Abstract
INTRODUCTION: Objectively-defined subtle cognitive decline (Obj-SCD) and plasma phosphorylated-tau181 (p-tau181) are promising early Alzheimer's disease (AD) markers. However, associations between Obj-SCD and p-tau181, and their combined prognostic potential, are unknown. METHODS: = 346) groups. CU and Obj-SCD participants were further classified as p-tau181-positive or negative. RESULTS: CU and Obj-SCD has lower baseline p-tau181 than MCI and did not differ from one another. Longitudinally, Obj-SCD had the steepest p-tau181 increase. Obj-SCD/p-tau181-positive participants had the fastest rates of amyloid accumulation, cognitive decline, and functional decline. CONCLUSIONS: Despite assumptions that cognitive changes invariably follow biomarker changes, early neuropsychological difficulties may emerge before/concurrently with plasma p-tau181 changes. Combining Obj-SCD and p-tau181, two potentially accessible early markers, was associated with the faster declines in AD-related outcomes.