People with thin brain structure are at greater risk of developing Alzheimer's, reveals study.
Led by Brad Dickerson, of the MGH department of neurology, the researchers enrolled men and women in their 70s with similar levels of education in two long-term research investigations of brain changes in older individuals, one based at Rush and the other at MGH.
The participants had a comprehensive clinical examination, neuropsychological evaluation including memory testing, and brain MR imaging.
At annual follow-up visits, each was reassessed to determine whether they were cognitively normal or if they had mild cognitive impairment or probable Alzheimer's dementia.
The study analyzed data from participants who were cognitively normal at the outset and had at least four follow-up visits - a group that totaled 50 participants who remained cognitively normal at the end of the study period, and 15 who had developed Alzheimer's over an average time span of about nine years.
In both study groups, the baseline MR images revealed that areas of the cerebral cortex associated with Alzheimer's in previous studies tended to be thinner in participants who went on to develop dementia.
Among those in whom these signature brain areas were the thinnest, 55 percent developed dementia during the study period, compared with 20 percent of those with average cortical thickness and none of those in whom cortical thickness was above average.
Participants with the thinnest cortical areas also developed Alzheimer's significantly faster than those with average thickness.
The study appears in April 13 issue of Neurology.