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

J Alzheimers Dis. 2011;27(3):627-37. doi: 10.3233/JAD-2011-110818.

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.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cerebral Cortex / pathology*
  • Cohort Studies
  • Female
  • Humans
  • Male
  • Memory Disorders / diagnosis*
  • Memory Disorders / psychology
  • Memory, Episodic*
  • Middle Aged
  • Plaque, Amyloid / diagnosis*
  • Plaque, Amyloid / psychology
  • Predictive Value of Tests
  • Prospective Studies
  • Residence Characteristics*