New Tests Could Predict Alzheimer's
Before Symptoms Appear, Tests Promise to Detect Alzheimer's Disease
WebMD News Archive
July 29, 2008 -- New tests promise to detect Alzheimer's disease before a person shows signs of dementia, giving treatments their best chance to prevent loss of mental function.
The tests aren't yet ready for prime time. But they mark progress in the quest to find ways to identify Alzheimer's disease in its earliest stages, says Samuel Gandy, MD, PhD, chairman of the medical and scientific advisory council to the Alzheimer's Association.
"Our eventual goal is to identify people with Alzheimer's disease before they ever have their first symptom," Gandy tells WebMD. "Even now [with no cure for Alzheimer's], such a test would be very useful for Alzheimer's-prevention trials. It is very hard to design prevention studies without a test to reliably identify those most at risk."
Promising reports on the tests came at this week's 2008 International Conference on Alzheimer's Disease, held July 26-31 in Chicago.
BACE1 in Spinal Fluid
Researchers have previously found that an enzyme called BACE1 is more active in the brains of people with Alzheimer's disease than in healthy people.
Might BACE1 in the spinal fluid predict Alzheimer's disease in people who, so far, only have mild cognitive impairment? Yes, find Harald Hampel of Trinity College in Dublin, Ireland, and colleagues in Germany and in the U.S.
In a two-part study, Hampel and colleagues first showed that the higher the BACE1 activity in spinal fluid, the higher the level beta-amyloid -- the main ingredient of the brain-clogging plaque that is the hallmark of Alzheimer's disease.
They then measured BACE1 levels in 47 people with mild cognitive impairment. Within two and a third years, 15 of these people developed Alzheimer's disease. A combined measure of high BACE1 level and presence of the ApoE gene linked to Alzheimer's was about 80% accurate in predicting Alzheimer's disease.
"We believe that BACE1 will be an excellent outcome biomarker to look at in ongoing clinical trials of anti-amyloid, disease modifying therapies," Hampel says in a news release. "Furthermore, we are working on a blood-based diagnostic test for BACE1 as well."
Alzheimer's Blood Test?
Obviously, an Alzheimer's screening test that requires a spinal tap will be of only limited use. While Hampel and colleagues work on developing a BACE1 blood test, a very different approach is making surprising progress.