'Cognitive Reserve' May Help Fight Alzheimer's

By Ed Edelson

12 nov 2008-- A study using an advanced brain scanning technology supports the growing body of evidence that education levels and some form of intellectual activity decrease the impact of Alzheimer's disease.

People with a greater "cognitive reserve" suffer less damage from the beta-amyloid plaques in the brain that are a leading marker of Alzheimer's disease, according to the study in the November issue of the Archives of Neurology.

Cognitive reserve is the concept that "the way that some people process information, the brain networks they use, allows them to cope better," said study author Catherine M. Roe, a research instructor in neurology at Washington University School of Medicine in St Louis.

The study used education levels as a yardstick of cognitive reserve, a customary practice in Alzheimer's studies, Roe said.

The researchers employed positron emission tomography (PET) scans to study the brains of 37 people with Alzheimer's-type dementia and 161 people with no dementia. All were injected with a radio-carbon-labeled compound that attaches itself to amyloid plaques, allowing the researchers to determine the size of those plaques in the brains of the participants. All the participants also took tests to measure their thinking ability.

"We divided the individuals into two groups, those with high uptake of the compound, indicating more plaques in the brain and those with low uptake, indicating few or no plaques," Roe said. "For people with low uptake, there was no relation to education in their cognitive scores. For high uptake, meaning significant plaques in the brain, we found an association with education. The more education they had, the fewer the symptoms of dementia."

So having a greater cognitive reserve, as measured by educational level, "may help you cope with that [Alzheimer's] pathology without having dementia symptoms," Roe said.

It's hard to say whether people can do anything to increase their cognitive reserve, said Yaakov Stern, professor of clinical neuropsychology at the Taub Institute for Research on Alzheimer's Disease at Columbia University and an originator of the cognitive reserve hypothesis.

Stern has taken part in several studies similar to the one now being reported, measuring blood flow to various parts of the brain as an indicator of Alzheimer's pathology. Those studies also showed that people with greater cognitive reserve "are walking around with more pathology than they exhibit," he said.

Whether people can consciously increase their cognitive reserve "is the big question," Stern said. "I am more and more convinced from studies like this that there are aspects of life experience that allow people to cope with Alzheimer's pathology better."

Any activities in particular? "We really don't know the recipe of what activity and how much would work," Stern said. "We really need controlled studies."

But, as a general rule, he said, "It doesn't hurt to remain active, physically as well as mentally. It's just that there are no studies to show that these activities really make a difference."