only way this fatal illness is diagnosed -- it may be too late. Such symptoms
now appear to be the result of irreversible brain damage .
"Even if we knew you had preclinical Alzheimer's disease in your brain and
ergo high risk of symptoms in a few years, we can't do anything about it now,"
Morris says. "So I really think we have to follow a dual course. We have to
clarify, refine, and define our clinical detection of Alzheimer's disease --
but at the same time we have to develop treatments for prevention. Because we
would like to couple knowing your risk with reducing your risk."
While the brain scans were able to detect the buildup of amyloid plaque in
the brain, a different test -- one that checks for Alzheimer's biomarkers in
cerebrospinal fluid -- may detect Alzheimer's risk even earlier.
Morris and colleagues studied one patient who eventually died with
Alzheimer's disease. He was positive for the biomarker but his brain scan did
not detect signs of Alzheimer's.
Kennedy says that's a hopeful finding. To him, it suggests that Alzheimer's
disease is not one single entity, but may be a family of diseases that may
respond to different treatments.
Morris notes that it's still too soon to be able to tell from brain scans or
biomarkers exactly how long it will take for a healthy person with
pre-Alzheimer's to develop dementia. But he expects this will eventually be
"As experience accumulates, we will be able to determine in these people who
carry lesions when they will get symptoms of Alzheimer's disease," he says. "It
will not be straightforward. It will vary with a host of individual factors.
But we can expect a day when we can tell people where they are in the course of
preclinical Alzheimer's disease, and their risk of dementia in one or 10 or 20
The Morris studies were funded with grants from the National Institute on
Aging, an anonymous foundation, and by the Knight Alzheimer's Research
Initiative of Washington University. The studies appear in the December issue
of Archives of Neurology.
By Daniel DeNoon
Reviewed by Louise Chang
©2005-2008 WebMD, LLC. All rights reserved