More schooling delayed disease onset, but decline was more rapid afterward, study finds
TUESDAY, Oct. 23 (HealthDay News) -- Having a higher level of education seems to delay the onset of dementia, but once cognitive decline begins, the descent is more precipitous, a new study finds.
The findings confirm the so-called "cognitive reserve hypothesis," which posits that people with more education have some kind of brain "reserve" that allows them to withstand the ravages of dementia longer. Eventually, however, the disease overwhelms this reserve, and the mental decline that follows is accelerated.
"The working hypothesis has been that people with higher education have some kind of reserve either in neuronal capacity or compensatory ability which allows the symptoms to be masked for a longer period of time," said study author Charles B. Hall, an associate professor of biostatistics in the department of epidemiology and population health and the department of neurology at Albert Einstein College of Medicine in New York City. His report was published in the Oct. 23 issue of Neurology.
Hall and his colleague set out to test the hypothesis by looking at 117 people who developed dementia (they were among an original group of 488 people).
Participants were followed for an average of six years, undergoing cognitive evaluations each year. Formal educational levels ranged from less than three years of elementary school to a post-graduate education.
For each additional year of formal education, the accelerated memory decline associated with dementia was delayed by about two-and-a-half months.
Once that accelerated decline stopped, however, the people with more education experienced a rate of cognitive decline about 4 percent faster for each additional year of schooling.
The practical implications of the study are limited for now, Hall said, because there are no effective interventions to change the natural history of Alzheimer's disease.
"However, as a practical matter, clinicians need to know the very heterogeneous presentation of dementia," he continued. "Particularly, the persons who are responsible for giving care to elderly people -- family members, parental caregivers and clinicians -- need to know that, in people with a lot of education, it is possible that the disease may progress at a more rapid rate than they would expect to see based on their experiences with other people who may not have had as much reserve."
The study pointed out the need for more research, particularly in the area of biological markers, to track how Alzheimer's and other forms of dementia are progressing.
"By the time people experience cognitive symptoms, there may well be quite a large amount of brain pathology, and once we do get treatments that are able to change the natural history, waiting until symptoms develop, particularly in highly educated people, may be too late to affect the disease process," Hall said. "A lot of people are looking for various biological markers of developing dementia. This, I think, magnifies the importance that that research continue."
The Alzheimer's Association' has a Maintain Your Brain program on keeping your brain healthy.
SOURCES: Charles B. Hall, Ph.D., associate professor, biostatistics, department of epidemiology and population health and department of neurology, Albert Einstein College of Medicine, New York City; Oct. 23, 2007, Neurology
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