UNIVERSITY PARK, Penn. -- A new study suggests that a series of fairly simple cognitive tests can predict which older adults will develop Alzheimer's disease or other dementia.
Those who scored poorly on the tests were 11 times more likely to show symptoms of dementia two years later than were their healthy counterparts.
"We're able to show that for the 'oldest old' -- those age 85 and older -- mild cognitive problems are reliable early markers of dementia," says Steven H. Zarit, Penn State professor of human development and a co-investigator on the project.
The tests can help distinguish between ordinary forgetfulness and the beginning of more serious, disabling memory loss, according to Zarit.
"One of the most difficult challenges is to differentiate benign memory problems -- which all of us have at every age -- from symptoms that herald the onset of decline," he says. "Sometimes people are concerned about their memory in late life, when in fact they don't have a problem. But sometimes, where there's smoke, there's fire."
The research was conducted by Boo Johannson of the University College of Health Sciences in Jonkoping, Sweden, and by Zarit, who is a faculty member in Penn State's College of Health and Human Development. Results are published in the January issue of the International Journal of Geriatric Psychiatry.
The study took place in Sweden, a country that has a larger proportion of people over age 85 than the United States does.
"Sweden's age distribution looks like the United States will in 10 to 20 years," Zarit says.
The study involved 324 people between the ages of 84 and 90. Most of the subjects -- 61 percent -- lived in ordinary housing, while 28 percent were in assisted-living arrangements and 12 percent were in nursing homes or similar institutions.
Registered nurses examined the participants four times over a six-year period, collecting data on health, functional abilities, mood, and related measures. They also gave each participant five tests of mental skills:
- Subjects were asked to put 10 objects (such as a comb, pencil, or bottle of pills) into a model of an apartment, then later were asked to recall what the objects were and into what rooms they had put them.
- A nurse told each subject a brief story and later asked him or her to re-tell it.
- A clock test measured the participants' ability to tell time.
- A coin test measured basic arithmetic skills using coins of different denominations.
- A 21-item Mini-Mental State Examination assessed memory, attention, verbal skills, and related abilities.
The researchers found that test scores not only could predict who would become impaired, but also who was likely to die in the next two to four years. Participants who scored poorly on the tests at the beginning of the study were three times more likely to die within the next two years (and five times more likely to die in the next four years) than the others were.
"There's speculation in the gerontology field that there may be a process separate from dementia, called terminal decline," Zarit explains. "The body goes through a general deterioration of its systems, and that's accompanied by increased cognitive difficulties.
"Some people think of it as running out of genetic programming for life. It's the body system wearing out, rather than a specific disease like cancer, heart disease, or Alzheimer's disease."
Having early warning about the approach of dementia -- or even death -- can give physicians, psychologists, social workers and other clinicians an important tool in working with older adults, Zarit says. The findings also give the elderly themselves time to prepare.
"People can make sure their legal and financial matters are in order -- for example, to give someone power of attorney," he says. "They also should think about where they want to live. For instance, if you're age 80 and you want to move to a retirement community, one of the questions to ask is whether they have programs to support you if you become cognitively impaired."
Almost a third of the subjects in Zarit's study already had some dementia (as measured by the American Psychiatric Association's criteria for the disorder) when the study began. That figure is consistent with what other studies have found, according to Zarit.
"Dementia is a big part of the picture for people over 85," he says, adding that the problem will grow as the population ages. "About 2-1/2 percent of the U.S. population is over 80. That's going to rise very quickly to 4 percent. That's a large growth, and in some ways we're totally unprepared.
"It's a group who will include a lot of competent, active people, but there are a lot of people with impaired memory who are going to need some help," he says.