Nov 10 2008
Scientists say brain scans show that education appears to lessen the effects of Alzheimer's disease.
The scientists from the Washington University School of Medicine, St. Louis, say their research supports the 'cognitive reserve' hypothesis and individuals with levels of higher education levels score higher on cognitive tests despite having Alzheimer's disease.
According to the hypothesis, individuals with greater cognitive (thinking, learning and memory) abilities are able to delay symptoms of Alzheimer's disease despite underlying changes in the brain.
Background information says education is commonly used as a substitute measure of cognitive reserve and greater education has been associated with better cognitive function during life and the researchers suggest that education interacts with Alzheimer disease to ease the effects of the disease symptoms by calling on that cognitive reserve.
For the research Dr Catherine M. Roe and colleagues studied 37 individuals with Alzheimer type dementia and 161 individuals without dementia between 2003 and 2008.
The participants reported their education history and took cognitive tests and were injected with a marker known as carbon 11-labelled Pittsburgh Compound B ([11C]PiB) and then underwent a 60-minute positron emission tomography (PET) scan of the brain.
Recent studies have shown that [11C]PiB adheres to beta-amyloid brain plaques associated with Alzheimer's disease, which allows researchers to identify these characteristics of the disease in living patients.
They found scans revealed that the level of [11C]PiB uptake interacted significantly with years of education in predicting cognitive test scores and among individuals whose brains took up higher levels of [11C]PiB, indicating the presence of beta-amyloid plaques, performance on the test increased with increasing education levels.
Education was not associated with cognitive scores among those with low [11C]PiB uptake, indicating no plaques.
The researchers say the results support the hypothesis that cognitive reserve influences the association between Alzheimer disease pathological burden and cognition.
They say there may be a ceiling effect when the extensive beta-amyloid pathological burden increases, and a greater proportion of highly educated participants will reach the threshold for dementia and the initial advantage provided by cognitive reserve decreases.
The research is published in the November issue of Archives of Neurology, one of the JAMA/Archives journals.
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