 By LEE BOWMAN Scripps Howard News Service November 01, 2007
The study was based on data from 856 people who took part in an aging and memory project through the University of Michigan Institute for Social Research and Duke University Medical Center. Each participant was assessed at home by a specially trained nurse and neuropsychology technician, using a typical memory evaluation format, along with a series of tests that measure memory, language, attention and problem-solving ability. A family member also was interviewed about how the person functioned in daily activities. Based on that sampling, the researchers calculate that about 3.4 million people, or 13.9 percent of the population age 71 and older, have some form of dementia -- most due to Alzheimer's disease (70 percent) or stroke (17.4 percent.) That's about 30 percent higher than previous estimates based on data from regional samples. And the prevalence of dementia increases dramatically with age -- while only about 5 percent of those aged 71 to 79 had the condition, it was found in 37.4 percent of those 90 and older. "These conditions affect millions of older Americans and touch nearly every family in some way, and the situation is only going to get worse as the population ages," said Brenda Plassman, a Duke researcher who was lead author of the study published in the journal Neuroepidemiology. Another recent study, published in the journal Neurology, found that people with more years of education lose their memory faster than those with less education once dementia begins. The study, led by Charles Hall of the Albert Einstein College of Medicine in New York City, looked at the experience of 117 patients, evaluating the advancement of dementia in each for an average of six years. The subjects ranged from those with less than three years of elementary school to those holding postgraduate degrees. It showed that for each additional year of formal education, accelerated memory decline associated with oncoming dementia was delayed by about 2-1/2 months. But once that first accelerated phase ended, those with more education had a rate of cognitive decline that was 4 percent faster for each additional year of education. "Higher levels of education delay the onset of dementia, but once it begins, accelerated memory loss is more rapid in people with more education," Hall said. "Our study showed that a person with 16 years of formal education would experience a rate of memory decline that is 50 percent faster than someone with just four years of education." Hall thinks the rapid decline may be explained by something called cognitive reserve -- the notion that a better-trained brain keeps its ability to function despite damage for a longer period of time. Once that reserve is overcome, the symptoms of memory decline seem to emerge more rapidly in the better educated, he said. Then again, still another study of mental function that looked at more than 3,600 people between the ages of 24 and 96 suggests that you don't need that college degree to preserve memory. Something as simple as spending 10 minutes talking with another person can improve memory and performance on tests, the researchers found. Phase one of the study was a survey that measured, among other things, the level of social interaction for each person. Those who had higher levels of social interactions -- such as talking on the phone or in person with friends, neighbors and relatives -- fared better on a short test of mental function. That held true for all age groups. A second phase of the experiment tested 76 college students, aged 18 to 21, on memory and mental performance after one of three different prep sessions. One group did a reading-comprehension exercise and a crossword puzzle. A second group spent 10 minutes in a discussion of a social issue. A control group watched a 10-minute clip of "Seinfeld." The results: Those who had a short-term social interaction for just 10 minutes had the same level of intellectual performance as those who did "intellectual" activities for the same amount of time. The "Seinfeld" group got no such bump. Oscar Ybarra, a psychologist at the University of Michigan Institute for Social Research, said as far as he knows, the study -- which will be published next year in the Personality and Social Psychology Bulletin -- provides the only cause-and-effect evidence "that social interaction directly affects memory and performance in a positive way." In other words, staying connected with people may be as important for staying sharp as doing a daily crossword puzzle, not to mention more helpful to our emotional well-being.
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