Investigators have long thought that highly educated people are less likely to develop symptoms of Alzheimer's disease. This has spawned the so-called "brain reserve" theory, the notion that the well educated are protected from cognitive decline, either because they have more neurons to lose or because they have a larger brain volume.
Neurologists now have to rethink this concept. New research indicates that current tests may only detect cognitive decline among people of average or little education, but are not designed to register cognitive changes in highly educated patients. If this is the case, then the "brain reserve" may be no more than a methodological shortcoming.
In a study presented recently to the International Neuropsychological Society, Holly Tuokko, Ph.D., a professor of psychology at the University of Victoria in Canada, reviewed data from the 1991 Canadian Study of Health and Aging, an epidemiological survey of dementia in 1,879 subjects. In 1996, Tuokko retested 844 subjects who exhibited no dementia in 1991. She classified the subjects' level of education as low at 0 to 5 years, medium at 6 to 12 years, or high at more than 13 years.