PT  - JOURNAL ARTICLE
AU  - Rebecca L. Koscik
AU  - Tobey J. Betthauser
AU  - Erin M. Jonaitis
AU  - Samantha L. Allison
AU  - Lindsay R. Clark
AU  - Bruce P. Hermann
AU  - Karly A. Cody
AU  - Jonathan W. Engle
AU  - Todd E. Barnhart
AU  - Charles K. Stone
AU  - Nathaniel A. Chin
AU  - Cynthia M. Carlsson
AU  - Sanjay Asthana
AU  - Bradley T. Christian
AU  - Sterling C. Johnson
TI  - Amyloid duration is associated with preclinical cognitive decline and tau PET
AID  - 10.1101/778415
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 778415
4099  - http://biorxiv.org/content/early/2019/09/23/778415.short
4100  - http://biorxiv.org/content/early/2019/09/23/778415.full
AB  - INTRODUCTION This study applies a novel algorithm to longitudinal amyloid positron emission tomography (PET) imaging to identify age-heterogeneous amyloid trajectory groups, estimate the age and duration (chronicity) of amyloid positivity, and investigate chronicity in relation to cognitive decline and tau burden.METHODS Cognitively unimpaired participants (n=257) underwent 1-4 amyloid PET scans. Group-based trajectory modeling was applied to participants with longitudinal scans (n=171) to identify and model amyloid trajectory groups, which were combined with Bayes’ theorem to estimate age and chronicity of amyloid positivity. Relationships between chronicity, cognition, clinical progression and tau PET (MK-6240) were investigated using regression models.RESULTS Chronicity explained more heterogeneity in amyloid binding than age and binary amyloid status. Chronicity was associated with faster cognitive decline, increased risk of abnormal cognition, and higher entorhinal tau.DISCUSSION Amyloid chronicity provides unique information about cognitive decline and neurofibrillary tangle development and may be useful to investigate preclinical AD.