Feature Archive

Should You Be Tested for Alzheimer's?

If you're terrified of the disease -- or it runs in your family -- you might want to get tested. Here's why.

By Gina Shaw
WebMD Feature

July 9, 2000 -- In the fall of 1998, Barbara and Les Dennis sat at the table in their Chicago home, deep in the throes of retirement planning. Barbara had printed out a spreadsheet showing their sources of income as well as the bills they'd have to pay. Les, a college professor in his early 60s, studied it and then tossed it back on the table. "It doesn't make any sense," he told her. Figuring that Les' poor eyesight was at fault, Barbara redid the spreadsheet, using larger and bolder type, and patiently began to explain the figures. But Les exploded in frustration: "You're just trying to figure out how you can save all the money until I die!"

"That's when I knew something was really wrong," Barbara says. Les wasn't the type to erupt in anger, he wasn't given to irrational fears -- and as a professor at Loyola University, he certainly wasn't a man to get confused over a column of numbers.

One month later, even Les agreed that something was wrong. He underwent testing for depression and anxiety. His brain was scanned for signs of a stroke. Finally, he took a battery of cognitive tests that gave him the diagnosis he dreaded: early Alzheimer's.

Just a few years ago, most of the estimated 4 million Americans with Alzheimer's weren't diagnosed until late in the disease, after they'd started getting lost on the way to the store or forgetting their grandchildren's names. But advances in early detection -- a primary theme at the World Alzheimer's Congress 2000 being held in Washington, D.C., from July 9-18 -- now make it possible for some to know that their brain is slowly deteriorating years before they fully lose their ability to think. Magnetic resonance imaging (MRI) can identify subtle changes in structures of the brain that relate to memory. Cognitive tests now can distinguish early Alzheimer's from minor memory lapses that come with age.

Looking More Closely at the Brain

Leading researchers say there are good reasons to seek early detection: People have time to plan, to try drug therapy, and to live their last good years fully. Yet such knowledge comes at a high price: With no cure yet in sight, people like Les Dennis must live with the awareness that they are gradually slipping into dementia.

"We're becoming aware that Alzheimer's doesn't start overnight and could be preceded by years of a vulnerable state," says Sandra Weintraub, PhD, director of neuropsychology at Northwestern University's Cognitive Neurology and Alzheimer's Disease Center. Only 3% of Americans are diagnosed with Alzheimer's between the ages of 65 and 74. But by age 85, a stunning 47% have the disease, according to the National Institute on Aging. By detecting Alzheimer's at the earliest point during those critical years, she says people like Les Dennis benefit from a "window of warning" -- time they can use to plan the care they'll need, to settle financial matters, or simply do the things they love the most.

Many of the tests are not new. Rather, in recent years researchers have grown more skilled at using them. One of the most reliable is the California Verbal Learning Test, which assesses skills such as verbal memory and problem solving.

"I'd tell you a story and ask you to tell it back to me immediately, then wait half an hour and ask you to tell it to me again," Weintraub says. Each of several such tasks taps a different brain system, and the combined results home in on the diagnosis of Alzheimer's with ever-increasing accuracy.

These cognitive tests are about 90% accurate in identifying people who have very mild dementia," says David Salmon, PhD, a professor in residence in the department of neurosciences at the University of California, San Diego.

New advances in MRI testing also help detect early onset of Alzheimer's and may someday be able to predict the disease before a person ever experiences that first subtle confusion. In people with early Alzheimer's, scientists have found that the hippocampus and the entorhinal cortex -- both essential parts of our brains' memory system -- show marked reductions in size and volume. In a study published in the April issue of the journal Annals of Neurology, researchers in Boston compared MRI scans of elderly people and found those that developed Alzheimer's disease showed significant changes in their brain scans over three years.

"This approach is not ready to be used clinically, but it is very encouraging and theoretically does provide a way to predict who will develop Alzheimer's," says Marilyn S. Albert, PhD, one of the study authors.