Study author Dr. Bradford Dickerson of Massachusetts General Hospital in Boston and Dr. David Wolk of University of Pennsylvania used brain scans to measure the thickness of regions of the brain's cortex in 159 people free of dementia with an average age of 76. At the beginning of the study and during the next three years, participants were given tests that measured memory, problem solving and ability to plan and pay attention.
Of the 159 subjects, 19 were classified as at high risk for having early Alzheimer's disease due to smaller size of particular regions known to be vulnerable to Alzheimer's in the brain's cortex, 116 were classified as average risk and 24 as low risk, Dickerson said.
The study, published in the online issue of Neurology, found 21 percent of those at high risk experienced cognitive decline during three years of follow-up after a magnetic resonance imaging scan -- compared to 7 percent of those at average risk and none of those at low risk.
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