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Mental Changes Show Up Long Before Alzheimer's Develops

From the WebMD Archives

June 14, 2000 -- Dolly Harne would sometimes escape the house and be found wandering around the neighborhood, with no coat in the winter or no umbrella in the rain. Her husband William would find her later, or someone would bring her back. After all, the neighbors all knew William had been caring for Dolly, who had Alzheimer's disease and a number of other chronic health conditions, at home for years.

Dolly died last year, but William Harne, a machinist who lives north of Baltimore, well remembers the frustration of knowing that nothing could be done about her Alzheimer's symptoms. "I would always wish that we could at least try something for Dolly's dementia, but when Dolly was diagnosed, 30 years ago, there was nothing to try," he says.

There remains very little to be done for Alzheimer's disease, but a study published in the Archives of Neurology shows that some types of tests of mental function can predict, years ahead of time, who may develop it. And that could help doctors design and test measures to try to head off or lessen the disease.

"What we were trying to do was assess whether a decline in cognitive ability predicts dementia, and which of a number of measures would be most sensitive to that," Merrill Elias, PhD, MPH, tells WebMD. "This study really confirms what other studies have shown, but it is unique in that we have followed so many patients for so long and found that certain measures were predictive." Elias is a research professor of epidemiology at Boston University.

Elias and colleagues analyzed data from people who have been participating in the so-called Framingham Study, a long-term study looking at many different diseases and conditions. Over 1,000 people were included in this particular study.

When the Framington Study began in the late 1970s, participants were tested using different tests of cognitive, or mental, function. Since then, they have been evaluated every few years. "What we have found is that tests of logical reasoning, retention of information, and abstract reasoning seem to act as indicators of who is at risk for developing Alzheimer's disease," Elias says. "But just because these tests may show a decline in cognitive function, that doesn't mean someone will necessarily develop Alzheimer's disease."

The study confirms the notion that changes that eventually result in Alzheimer's disease are going on years before the disease is diagnosed, says Paul Fishman, MD, a professor of neurology at the University of Maryland School of Medicine who commented on the study for WebMD. "The question from a public-health perspective is, Can we identify those at risk of developing Alzheimer's at an early date, particularly if we have an intervention that can slow or prevent the disease? If so, tests such as these might be really useful," he says.

Knowing who is at risk of developing the disease can also help researchers assess the effectiveness of treatments, Fishman says: "For example, we know that vitamin E may be beneficial in some people with Alzheimer's disease, but how much more beneficial might it be earlier in the disease? If we can identify those at risk, we have a potential population in whom testing interventions might make sense."

Elias says the long-term study is already giving researchers some ideas about potential interventions.

"The Framingham Study is providing us with a lot of interesting associations between cognitive impairment and other chronic conditions, such as diabetes," he says. "These are conditions where people can control or reduce their risk factors by watching their diet, controlling their high blood pressure, and exercising, for example. If we can make a connection between mental function and these behaviors, it would be a powerful stimulus for people to change their lifestyle to reduce their risk."

For more information from WebMD, visit our Diseases and Conditions Alzheimer's page.

Vital Information:

  • In a recent study, researchers found that changes in mental functions may predict whether a person will go on to develop Alzheimer's disease.
  • Tests of logical reasoning, retention of information, and abstract reasoning were all indicators of risk for Alzheimer's disease. But scoring poorly on these tests does not guarantee that a person will develop the disease.
  • Predicting who will get Alzheimer's may be an important tool one day, if researchers can develop treatments to prevent or slow the disease's progression.