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Cognition and beta-amyloid in preclinical Alzheimer's disease: data from the AIBL study.
- Source :
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Neuropsychologia [Neuropsychologia] 2011 Jul; Vol. 49 (9), pp. 2384-90. Date of Electronic Publication: 2011 Apr 16. - Publication Year :
- 2011
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Abstract
- The 'preclinical' phase of Alzheimer's disease is a future target for treatment, but additional research is essential to understand the relationship between β-amyloid burden and cognition during this time. We investigated this relationship using a large sample of apparently healthy older adults (N=177), which also enabled examination of whether the relationship differed according to age, gender, years of education, apolipoprotein E status, and the presence of subjective memory complaints. In addition to episodic memory, a range of cognitive measures (global cognition, semantic memory, visuospatial performance, and executive function) were examined. Participants were aged over 60 years with no objective cognitive impairment and came from the imaging arm of the Australian Imaging, Biomarkers, and Lifestyle (AIBL) study of ageing. (11)C-PiB PET was used to measure β-amyloid burden and a PiB 'cut-off' level of 1.5 was used to separate participants with low PiB retention from those with high PiB retention. Thirty-three percent of participants had a PiB positive scan. PiB positive participants were 5 years older, twice as likely to carry an apolipoprotein E ɛ4 allele, and their composite episodic memory was 0.26 SD worse than PiB negative volunteers. Linear regressions with β-amyloid burden as a dichotomous predictor, revealed an interaction between β-amyloid burden and gender, as well as age and education effects, in predicting episodic memory and visuospatial performance. In females, but not in males, increased β-amyloid was related to worse episodic memory and visuospatial performance. Furthermore, an interaction between β-amyloid burden and APOE status was found in predicting visuospatial performance, whereby there was a trend for increased β-amyloid to relate to worse visuospatial performance for those without an APOE ɛ4 allele. There were no other main or interaction effects of β-amyloid on any of the other composite cognitive measures. These cross-sectional findings suggest that β-amyloid burden does not have a large effect on cognition in this subset of apparently healthy older people. The finding of gender differences deserves further research to answer definitively the important question of gender susceptibility to adverse cognitive effects from β-amyloid.<br /> (Copyright © 2011 Elsevier Ltd. All rights reserved.)
- Subjects :
- Age Factors
Aged
Aged, 80 and over
Alzheimer Disease complications
Alzheimer Disease diagnostic imaging
Alzheimer Disease metabolism
Alzheimer Disease pathology
Amyloid beta-Peptides adverse effects
Aniline Compounds
Benzothiazoles
Carbon Radioisotopes
Case-Control Studies
Cerebral Cortex diagnostic imaging
Cerebral Cortex metabolism
Cerebral Cortex physiopathology
Cognition Disorders complications
Cognition Disorders diagnostic imaging
Cognition Disorders metabolism
Cognition Disorders pathology
Cohort Studies
Cross-Sectional Studies
Early Diagnosis
Female
Humans
Longitudinal Studies
Male
Middle Aged
Neuropsychological Tests
Radionuclide Imaging
Reference Values
Sex Factors
Thiazoles
Alzheimer Disease diagnosis
Amyloid beta-Peptides metabolism
Cerebral Cortex pathology
Cognition Disorders etiology
Subjects
Details
- Language :
- English
- ISSN :
- 1873-3514
- Volume :
- 49
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- Neuropsychologia
- Publication Type :
- Academic Journal
- Accession number :
- 21529702
- Full Text :
- https://doi.org/10.1016/j.neuropsychologia.2011.04.012