Episodic memory decline predicts cortical amyloid status in community-dwelling older adults

David G. Darby, Amy Brodtmann, Robert H Pietrzak, Julia Fredrickson, Michael Woodward, Victor L Villemagne, Amy Fredrickson, Paul Maruff, Christopher Rowe

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27 Citations (Scopus)

Abstract

Intra-individual decline in memory and cognition is characteristic of prodromal Alzheimer's disease (AD) and may allow detection of very early AD pathology. Episodic memory task scores on a brief computerized cognitive battery (CogState) were prospectively evaluated at baseline, and 3-, 6-, 9-, 12-, and 24-months post-baseline. Linear mixed models were conducted to compute age-adjusted slopes. Subjects with slopes declining ≥90th percentile ("memory decliners") and age- and gender-matched subjects without such decline ("non-decliners") were studied with clinical, neuropsychological, and neuroimaging evaluations. Of 195 who completed 24-month evaluation (age 51 to 80 years), 15 memory decliners (mean age 62.7 years, SD 7.6) were identified, and matched with 33 non-decliners (mean age 63.3 years, SD 8.2). Amyloid-PET imaging was qualitatively abnormal with excess cortical amyloid accumulation in 7 memory decliners (46.7%) and 4 (12.1%) non-decliners (odds ratio 6.34), and quantitatively abnormal with standardized uptake value ratios >1.4 in 5 memory decliners (33.3%) and 2 (6.1%) non-decliners (odds ratio 8.3). One of the memory decliners and none of the non-decliners fulfilled criteria for mild cognitive impairment, but the groups did not differ with respect to subjective memory impairment, neuropsychological evidence of episodic memory impairment, or MRI imaging abnormalities. Intra-individual decline in episodic memory can be detected using a brief computerized cognitive performance test optimized to detect change in community-dwelling non-demented older persons and appears predictive of the presence of cerebral amyloid in about half of these persons. This approach may help detect early prodromal AD pathology in wider-scale community screening programs.

Original languageEnglish
Pages (from-to)627-637
Number of pages11
JournalJournal of Alzheimer's Disease
Volume27
Issue number3
DOIs
Publication statusPublished - 2011
Externally publishedYes

Keywords

  • Alzheimer's disease
  • cognition
  • cognitive decline
  • memory
  • pre-clinical diagnosis

Cite this

Darby, D. G., Brodtmann, A., Pietrzak, R. H., Fredrickson, J., Woodward, M., Villemagne, V. L., Fredrickson, A., Maruff, P., & Rowe, C. (2011). Episodic memory decline predicts cortical amyloid status in community-dwelling older adults. Journal of Alzheimer's Disease, 27(3), 627-637. https://doi.org/10.3233/JAD-2011-110818