Mental Agility Doesn't Always Fade With Age, Study Suggests
A group of mentally agile elders, as quick-witted at 75 as people less than half their age, are burying the adage ``sound mind, sound body.'' They are showing that some people stay young mentally even when age robs them of physical health.
The findings come from a Harvard University study of 1,003 physicians, ages 28 to 92, who were tested for mental agility. Although the study found an overall gradual decline in mental function that started at age 65, some elders were in a class by themselves.
The top 10 scorers among those over age 75, for example, were as sharp, on average, as those under age 35.
``I thought that was pretty astonishing,'' says Marcia Weintraub, the Harvard psychologist who reported her findings recently at a meeting of the American Association for the Advancement of Science. ``Our 35-year-olds were pretty sharp.''
What could explain this? Not physical health. The mentally agile elders were no more or less physically healthy than others their age who showed clear mental decline.
``We blew apart the thesis that there's a correlation between physical and mental fitness,'' says Douglas H. Powell, another Harvard researcher who worked with Weintraub on the study.
Powell and others are intrigued with the findings. They say the study suggests that people can vary greatly in the way they age mentally.
``At one extreme are women and men who retain intellectual vigor well into their 70s,'' Powell says. ``At the other extreme are those afflicted with Alzheimer's disease.''
If researchers can discover what separates the super-septuagenarians from those merely average, Powell says, the answers could have implications for us all. ``Is it possible to enhance mental vigor?'' he asks.
The 1,003 physicians were given a battery of 19 tests that measured four areas of mental function: attention, memory, reasoning and interpreting visual patterns.
They were divided into six groups according to age: the youngest were under 35, the oldest over 75.
Overall, the results showed an eventual average decline in mental function with age.
``Until age 65, there is little difference with the under-35 group,'' Weintraub says. ``By the age of 75, average test scores in almost all (test) domains were significantly lower.''
But when Weintraub looked at the top 10 scorers in the 75-plus age group, she found that their total scores on all 19 tests were within the range of average for those under 35.
What set these superior elders apart from their peers? The most logical explanation would be that they enjoyed better physical health than others their age. But the Harvard study found that was not the case.
The top-10 scorers in the 75-plus group, for example, were no less likely than bottom-10 scorers the same age to suffer from high blood pressure, diabetes, cancer, depression or neurological illness. Nor were they any less likely to be taking prescription medicine for these or other medical complaints.
Another logical explanation - the ``use it or lose it'' phenomenon - may or may not play a part. The top-10 scorers were far less likely to be retired than their bottom-10 counterparts.
But Weintraub says it is more likely the top-10 scorers' decision to keep working is the result, not the cause, of their mental ability.
``I don't believe in the `use it or lose it' explanation,'' she says. ``If you're having trouble with your thinking and mental abilities, you're not going to be working.''
Others have suggested that educational level may play a part in why some people retain their mental ability longer than others as they age. If so, they say, is it possible to teach people how to reverse their mental decline?
One 1987 review of research on mental and physical aging, for example, cites Pennsylvania State University researchers who have ``trained'' people to recover some of the mental function they lose as they age.
The people undergoing the training had been tested for mental function 14 years earlier as part of a project called the Seattle Longitudinal Study. At the time of the training, in 1984, they were, on average, 73 years old. Some of them had shown a gradual decline in mental function over 14 years while others had not.
After undergoing five one-hour training sessions to improve reasoning and spatial-visual function, 62 percent of the ``decliners'' recovered most of their mental function. Forty percent had recovered all of their mental ability or even improved.
Among those who had not shown any previous mental decline, the training sessions appeared to enhance their mental abilities in many cases.