Readers of ScienceNOW will be gratified to learn of new evidence that intellectual activity helps stave off senility. The latest is from a brain scan study of older adults, showing that those with more education seem to be less affected cognitively by the brain shrinkage that accompanies aging.
The study, headed by neuropsychiatrist C. Edward Coffey of the Henry Ford Health System in Detroit, looked at the brains of 320 cognitively normal men and women between the ages of 66 and 90 who had between 4 and 17 years of formal education. The researchers found that when they controlled for age, sex, and intracranial size, those with a college degree had 8% to 10% greater volume of peripheral cerebrospinal fluid--an indicator of brain shrinkage--than those with 4 years of schooling. What this means, says Coffey, is that the more educated people in the sample were still functioning cognitively even when their brains had reached a level of atrophy that would cause mental deficits in a less educated person, driving them out of the study sample.
This research, he says, is "the first to provide direct neurobiological support" in healthy adults for the "reserve" hypothesis, the notion that mental activity provides a buffer against cognitive decline. Some theorize that it creates a richer and more redundant array of neural connections. "The brain really likes novelty," observes Coffey, whose study appears in the 13 July issue of Neurology.
Richard Suzman, associate director for behavioral and social research at the National Institute on Aging, calls the study "fascinating," and says it fits with other research showing that people with more education--including a sample of nuns--live longer and postpone the onset of dementia. "How education shapes the brain is one of those mysteries that deserves much more study," he says.