Cognitive impairment and decline in cognitively normal older adults with high amyloid-β: A meta-analysis

Jenalle E. Baker, Yen Ying Lim, Robert H. Pietrzak, Jason Hassenstab, Peter J. Snyder, Colin L. Masters, Paul Maruff

Research output: Contribution to journalReview ArticleResearchpeer-review

61 Citations (Scopus)

Abstract

Introduction This meta-analysis aimed to characterize the nature and magnitude of amyloid (Aβ)-related cognitive impairment and decline in cognitively normal (CN) older individuals. Method MEDLINE Ovid was searched from 2012 to June 2016 for studies reporting relationships between cerebrospinal fluid or positron emission tomography (PET) Aβ levels and cognitive impairment (cross-sectional) and decline (longitudinal) in CN older adults. Neuropsychological data were classified into domains of episodic memory, executive function, working memory, processing speed, visuospatial function, semantic memory, and global cognition. Type of Aβ measure, how Aβ burden was analyzed, inclusion of control variables, and clinical criteria used to exclude participants, were considered as moderators. Random-effects models were used for analyses with effect sizes expressed as Cohen's d. Results A total of 38 studies met inclusion criteria contributing 30 cross-sectional (N = 5005) and 14 longitudinal (N = 2584) samples. Aβ-related cognitive impairment was observed for global cognition (d = 0.32), visuospatial function (d = 0.25), processing speed (d = 0.18), episodic memory, and executive function (both d's = 0.15), with decline observed for global cognition (d = 0.30), semantic memory (d = 0.28), visuospatial function (d = 0.25), and episodic memory (d = 0.24). Aβ-related impairment was moderated by age, amyloid measure, type of analysis, and inclusion of control variables and decline moderated by amyloid measure, type of analysis, inclusion of control variables, and exclusion criteria used. Discussion CN older adults with high Aβ show a small general cognitive impairment and small to moderate decline in episodic memory, visuospatial function, semantic memory, and global cognition.

Original languageEnglish
Pages (from-to)108-121
Number of pages14
JournalAlzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring
Volume6
Issue number1
DOIs
Publication statusPublished - 2017
Externally publishedYes

Keywords

  • Amyloid-beta
  • Cognition
  • Decline
  • Impairment
  • Meta-analysis
  • Preclinical Alzheimer's disease

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