Well-educated people and those in high-status jobs appear to be better able to fend off the symptoms of mental decline in later life, it was reported recently.
A growing number of studies show that the higher a person's IQ, the less likely they are to succumb to dementia and even brain damage caused by injuries.
It should even be possible to fight senility with some well-chosen mental gymnastics, according to the report in New Scientist magazine.
Scientists have been puzzled as to why people who lead more intellectually stimulating lives are somehow protected from mental decline. Some psychologists and neuroscientists have started referring to this as their "cognitive reserve."
One theory is that the brains of people with higher levels of "cognitive reserve" are better able to switch to "plan b" when there are problems. Other experts believe they are simply more able to increase the efficiency of their existing brain networks.
The idea could explain why it seems people with high IQ levels go downhill unusually quickly when they do show symptoms of a disease such as Alzheimer's.
Michael Rutter, from the Institute of Psychiatry in London, England, told the magazine that people with high education and with Alzheimer's disease do not actually deteriorate faster. Instead, they combat the symptoms more effectively so that by the time the problems appear, they are at a relatively late stage of the disease.
Researchers believe the best predictor of cognitive ability in middle age is a person's IQ score at 8 years old. This does not mean people cannot boost their brain power later in life to try to increase their protection, according to the report.
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