Reduced volume, or atrophy, in parts of the brain known as the amygdala and hippocampus may predict which cognitively healthy elderly people will develop dementia over a six-year period, according to a study in the January issue of Archives of General Psychiatry, one of the JAMA/Archives journals.
New strategies may be able to prevent or delay the onset of Alzheimer's disease (AD), the most common cause of dementia among older adults, according to background information in the article. Accurate methods of identifying which people are at high risk for dementia in old age would help physicians determine who could benefit from these interventions. There is evidence that adults with AD and mild cognitive impairment, a less severe condition that is considered a risk factor for AD, have reduced hippocampal and amygdalar volumes. However, previous research has not addressed whether measuring atrophy using magnetic resonance imaging (MRI) can predict the onset of AD at an earlier stage, before cognitive symptoms appear.
Tom den Heijer, M.D., Ph.D., of the Erasmus Medical Center, Rotterdam, the Netherlands, and colleagues used MRI to assess the brain volumes of 511 dementia-free elderly people who were part of the Rotterdam Study, a large population-based cohort study that began in 1990. They screened the participants for dementia at initial visits in 1995 and 1996 and then in follow-up visits between 1997 and 2003, during which they asked about memory problems and performed extensive neuropsychological testing. The authors also monitored the medical records of all participants. During the follow-up, 35 participants developed dementia and 26 were diagnosed with AD.