Early diagnosis of Alzheimer's disease is important now that drugs can slow mental decline. But clinicians shouldn't rely solely on cognitive tests, says a leading expert in the field, because loved ones know a patient best. Alzheimer's disease, which affects more than 4 million Americans, creates problems with memory, speech and perception. Among adult Americans, it is the fourth leading cause of death.
John C. Morris, M.D., recently presented a paper on the early diagnosis of Alzheimer's disease during a satellite symposium at the Congress of the International Psychogeriatric Association in Vancouver, Canada. He is the Harvey A. and Dorismae Hacker Friedman Professor of Neurology at Washington University School of Medicine in St. Louis. He also co-directs the school's Alzheimer's Disease Research Center.
Research at the center and other institutions suggests that information from a person close to a patient is even more valuable than cognitive tests in the very early stages of Alzheimer's disease. Cognitive tests, such as reading a paragraph and recalling what you have read, assess current mental performance. "But they don't tell us how that performance relates to what that person once did," Morris says. "So someone who is well educated and bright could lose a substantial amount of intellectual ability and still do well on a screening test."
Morris cites the example of President Ronald Reagan, whose Alzheimer's disease perhaps began in the White House. "But his native abilities and extensive support system allowed him to continue to perform in a very demanding position," Morris says.
When Morris assesses a patient, he conducts a structured interview with a spouse, adult child, close friend or colleague. "That helps us determine not only how an individual has changed relative to his or her own past performance but also whether that change is interfering with everyday activities," Morris says.
He recalls a banker who successfully managed his finances until he was in his early 80s. But one spring, the banker shipped his records to an accountant. That would be normal behavior for someone who had never prepared his own tax return.
But the banker always had, so something was amiss. "It's important to always relate performance to what that person was once able to do," Morris says. In early-stage Alzheimer's disease, some people may still pay bills but have difficulty balancing the checkbook. Or they might hesitate while driving because they can't remember whether to turn left or right. Yet others may choose to cook simple rather than gourmet meals because recipes seem too complex. "But all of these patients might do well on a mental status screening test," Morris points out.
In research conducted with Eugene H. Rubin, Ph.D., professor of psychiatry, Morris and colleagues at Washington University's Memory and Aging Project previously found that scores on cognitive tests don't decline much with age unless a person develops a dementing illness such as Alzheimer's disease. "But when cognitive performance begins to decline, it does so only when the informant-based method has shown change," Morris says. "The informant method can be more sensitive to the very early stages of dementia than standard psychometric tests."
Early diagnosis important
There are three advantages of early diagnosis, Morris adds. First, people in the
early stages of Alzheimer's disease often can still make sound decisions. "It is
appropriate for them to become involved in managing their illness," Morris says.
"For example, they may want to indicate who they would like to manage their finances or make medical decisions for them if they become incapacitated." Second, there now are treatments -- though not cures -- for Alzheimer's disease. These drugs, called cholinesterase inhibitors, may relieve symptoms and delay progression of the disorder for six months or even longer. "I like to start treatment in the early stages, when a patient's function is still good rather than wait until it drops way down," Morris says.
Third, promising new treatments are on the horizon. This summer, for example, a San Francisco company tested a vaccine on genetically modified mice that make a human brain protein associated with Alzheimer's disease. The vaccine prevented the mice from depositing the protein. And even when deposits already were in the brain, it appeared to reduce them.
"Although we don't have agents now that will cure the disease, studies such as the vaccination of mice suggest that we are not far from developing such strategies for humans," Morris says. "People who are diagnosed early will be in a position to benefit as these treatments come down the pipeline. By utilizing information from someone who knows a patient well, we can diagnose Alzheimer's disease at an earlier stage than is common now."
Note: The August 1999 Vancouver symposium, Challenging Current Paradigms in the Treatment of Alzheimer's Disease, was sponsored by Janssen-Cilag, which produces one of the drugs used to treat Alzheimer's disease.