“Certain things increase or decrease your vulnerability to cognitive [mental] decline,” said Robert Wilson, the study’s lead author. Keeping your brain active seems to help certain brain circuits operate effectively, even if a gradual buildup of brain disease is already occurring, said Wilson, a professor of neurological and behavioral sciences at Rush University Medical Center, in Chicago. People who engaged in frequent mental activity in later life had a rate of mental decline that was 32 percent lower than those with average activity. Meanwhile, those with infrequent mental activity experienced a decline in mental abilities that was 48 percent faster.
The research, published online July 3 in the journal Neurology, helps explain why one-third of people die in old age with little or no signs of problems with thinking, learning or memory, yet when brain autopsies are done, they actually have clear evidence of Alzheimer’s disease, Wilson said. “They [technically] have the disease, but it’s not expressed clinically,” he said. That idea that the brain somehow creates a “work-around” to avoid showing signs of Alzheimer’s or other dementia is often referred to as the “cognitive reserve hypothesis,” Wilson said. That concept suggests that people with greater thinking, learning and memory abilities are somehow able to delay symptoms of Alzheimer’s. But proving the hypothesis has been challenging for scientists. “There’s been this long-term debate in the field about how cognitive activities preserve cognition,” said Prashanthi Vemuri, an assistant professor of radiology at the Mayo Clinic in Rochester, Minn., who wrote an editorial accompanying the study. The question has essentially been: Which comes first, the chicken or the egg?
“Does engagement in cognitive activities slow cognitive decline, or are people less interested in doing cognitive activities because they have problems with dementia?” Vemuri said. She thinks the study breaks new ground.
Source: http://tinyurl.com/kmrcbdv
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