title: Cognitive trajectories associated with β-amyloid deposition in the oldest-old without dementia.
abstract: 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 < 0.01) and Raven's Progressive Matrices (p = 0.05), with trend level difference for Block Design (p = 0.07). Longitudinal analyses showed significant slope differences for immediate and delayed recall of the Rey-Osterrieth figure, semantic fluency, and Trail-Making Test parts A and B, indicating greater performance decline prior to neuroimaging for Aβ-positive relative to Aβ-negative participants (ps < 0.05).
  
  
  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.
authors.affiliation: Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA. snitzbe@upmc.edu
authors.forename: Beth E
authors.initials: BE
authors.lastname: Snitz
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Weissfeld
authors.forename: Oscar L
authors.initials: OL
authors.lastname: Lopez
authors.forename: Lewis H
authors.initials: LH
authors.lastname: Kuller
authors.forename: Judith
authors.initials: J
authors.lastname: Saxton
authors.forename: Dilrukshika M
authors.initials: DM
authors.lastname: Singhabahu
authors.forename: William E
authors.initials: WE
authors.lastname: Klunk
authors.forename: Chester A
authors.initials: CA
authors.lastname: Mathis
authors.forename: Julie C
authors.initials: JC
authors.lastname: Price
authors.forename: Diane G
authors.initials: DG
authors.lastname: Ives
authors.forename: Ann D
authors.initials: AD
authors.lastname: Cohen
authors.forename: Eric
authors.initials: E
authors.lastname: McDade
authors.forename: Steven T
authors.initials: ST
authors.lastname: Dekosky
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds; D003072:Cognition Disorders / Q000150:complications* / Q000188:drug therapy; D003430:Cross-Sectional Studies; D003704:Dementia / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D004311:Double-Blind Method; D005260:Female; D020441:Ginkgo biloba; D006801:Humans; D016014:Linear Models; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D008517:Phytotherapy / Q000379:methods*; D028321:Plant Preparations / Q000627:therapeutic use*; D049268:Positron-Emission Tomography; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies; D013844:Thiazoles
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D028321:Plant Preparations; D013844:Thiazoles