Both are shades of the truth, actually. Here’s what the scientists actually found:
Robert Wilson and his colleagues have been tracking more than a thousand people as part of their long-term study, begun in the early 1990s. The patients were 65 or older and the scientists interviewed them every three years.
Participants indicated on a 5-point scale how often they participated in seven activities: viewing television, listening to radio; reading newspapers; reading magazines; reading books; playing games like cards or doing puzzles; and going to museums. (A rating of 5 meant a person did some of these activities about every day; 3 meant several times a month; 1 meant once a year or less) [LiveScience].
At the time of the interview, the patient was also screened for signs of dementia and Alzheimer’s. What the scientists saw in the study participants was this: If the person did not have any kind of cognitive impairment, their normal cognitive decline slowed by 52 percent for each point they scored on the activity scale. But once the person was diagnosed with Alzheimer’s or dementia, their rate of cognitive decline was 42 percent faster for every point higher on the activity scale.
To put it a simpler way: Yes, seniors stay sharper longer when they exercise their minds. But the catch is that Alzheimer’s goes unnoticed for longer, masked by the cognitive ability of mentally active people. So, when the disease is finally noticed, its effects are more pronounced because the brain degeneration has already progressed.
This idea fits in with the “cognitive reserve” hypothesis of dementia. That theory basically holds that people who are mentally active can better withstand the gradual brain-cell damage that marks Alzheimer’s disease and other forms of dementia. But once that damage reaches a certain threshold, dementia symptoms will become apparent [MSNBC].
Neuropsychologist Yaakov Stern notes that there’s no way to know, at least not yet, exactly how much mental activity and what kind will produce the maximum benefit. But for his money, he’d take the extended benefit of cognitive ability, even if it came with a faster decline later on.
When dementia does come later and progress more quickly, experts say, that might be a good thing. “It’s not bad to have more good years of life and fewer years of bad life,” Stern said. “I think it’s a good deal” [Discovery News].
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