Cognitive trajectories associated with β-amyloid deposition in the oldest-old without dementia

OBJECTIVE: To determine whether a high prevalence (55%) of Aβ deposition in a cohort of individuals remaining dementia-free into their 9th and 10th decades is associated with cognitive decline prior to imaging.
METHODS: A total of 194 participants (mean age 85.5 years, range 82-95) who completed the Ginkgo Evaluation of Memory Study (GEMS) and remained dementia-free subsequently completed Pittsburgh compound B-PET imaging. We examined cross-sectional associations between Aβ status and performance on a broad neuropsychological test battery completed at GEMS entry 7-9 years prior to neuroimaging. We also longitudinally examined cognition over annual evaluations using linear mixed models.
RESULTS: At GEMS screening (2000-2002), participants who were Aβ-positive in 2009 had lower performance on the Stroop test (p CONCLUSIONS: Highly prevalent Aβ deposition in oldest-older adults is associated with cognitive decline in visual memory, semantic fluency, and psychomotor speed beginning 7-9 years prior to neuroimaging. Mean differences in nonmemory domains, primarily executive functions, between Aβ-status groups may be detectable 7-9 years before neuroimaging.