Cognitive indicators of transition to preclinical and prodromal stages of Alzheimer's disease in Down syndrome

Introduction: There is a critical need to identify measures of cognitive functioning sensitive to early Alzheimer's disease (AD) pathophysiology in Down syndrome to advance clinical trial research in this at-risk population. The objective of the study was to longitudinally track performance on cognitive measures in relation to neocortical and striatal amyloid beta (A beta) in non-demented Down syndrome. Methods: The study included 118 non-demented adults with Down syndrome who participated in two to five points of data collection, spanning 1.5 to 8 years. Episodic memory, visual attention and executive functioning, and motor planning and coordination were assessed. A beta was measured via [C-11] Pittsburgh Compound-B (PiB) PET. Results: PiB was associated with level and rate of decline in cognitive performance in episodic memory, visual attention, executive functioning, and visuospatial ability in models controlling for chronological age. Discussion: The Cued Recall Test emerged as a promising indicator of transition from preclinical to prodromal AD.