Effects of age and β-amyloid on cognitive changes in normal elderly people - PubMed (original) (raw)

Effects of age and β-amyloid on cognitive changes in normal elderly people

Hwamee Oh et al. Neurobiol Aging. 2012 Dec.

Abstract

Age-related decline is common in multiple cognitive domains. β-amyloid (Aβ) deposition, a pathological hallmark of Alzheimer's disease, is also associated with cognitive changes in many older people. In this study, we examined a wide range of cognitive function in order to differentiate the effect of age and Aβ on cognition during aging. Using positron emission tomography (PET) imaging with the radiotracer Pittsburgh Compound B (PIB), we classified normal older subjects as High PIB-Old and Low PIB-Old and applied sequential multivariate analyses (i.e., principal components analysis [PCA] and discriminant analysis) to obtain summary measures of cognitive tests encompassing multiple cognitive domains. Among 5 cognitive components, a significant age effect was observed in component scores of visual memory and executive functions, regardless of the level of Aβ. Discriminant scores (weighted scores of the 5 cognitive components) revealed a significant effect of both age and Aβ and were further associated with quantitative PIB counts. The results of the current study highlight both effects of age and Aβ on cognitive changes in normal elderly.

Copyright © 2012 Elsevier Inc. All rights reserved.

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Conflict of interest statement

Conflict of interest statement

Dr. Jagust has served as a consultant to GE Healthcare and Bayer Healthcare which manufacture amyloid imaging agents.

The other authors have no conflicts of interest.

Figures

Figure 1

Figure 1

Bar graphs represent mean factor scores by Young, Low PIB-Old, and High PIB-Old groups. Significant differences were detected on visual memory and executive function factor scores between Young and Low PIB-Old groups and between Young and High PIB-Old groups. * p < .05, *** p < .001.

Figure 2

Figure 2

Bar graph representing mean discriminant scores obtained from the first discriminant function by Young, Low PIB-Old, and High PIB-Old groups. * p < .05, *** p < .001.

Figure 3

Figure 3

Scatterplot illustrating subjects’ group memberships as a function of two discriminant function scores.

Figure 4

Figure 4

Sensitivity and specificity plots of discriminant scores created by the first discriminant function. Red lines represent the ROC curve.

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