MONDAY, Sept. 21, 2009 (HealthDay News) -- Scientists have assumed that people's brains shrink as they age, but researchers now suspect that's not the case.
A study in the September issue of Neuropsychology examines long-term Dutch research into aging brains, which used neurological tests and MRI scans to measure parts of the brain.
The researchers looked at data from 1994 to 2005 for two groups: 35 people who were cognitively healthy and 30 people who did not have dementia but experienced cognitive decline during the time period. Both groups averaged about 69 years old.
Those whose cognitive skills declined also had brain shrinkage. That suggested to the researchers that the brain may not shrink much among healthy, older people who don't suffer from cognitive decline.
Scientists in the past had failed to screen out people whose brains had shrunk because of brain disease, they said.
In other words, simply growing older may not make the brain become smaller.
"If future longitudinal studies find similar results, our conception of 'normal' brain aging may become more optimistic," the study's lead author, Saartje Burgmans, a graduate student at Maastricht University in Holland, said in a news release from the American Psychological Association.
Harvard Medical School has more about the brain.