May 23--Drugs developed to treat Alzheimer's disease have failed to stop its
progression in people experiencing mental decline. The challenge for scientists
is to find out if the disease can be identified and treated before people show
Researchers at Washington University have been part of the effort to identify
biological markers in spinal fluid and brain scans that can indicate a person's
risk of Alzheimer's. New research from the medical school offers evidence that
the different markers are equally accurate in predicting who will become
The scientists looked at 200 participants in a study funded partly by the
National Institute on Aging and published this month in the journal Neurology.
Participants were 45 to 88 years old and tracked for an average of four years.
Researchers looked at their brain scans, which can show plaques that are
indicators of Alzheimer's. They measured the amount of proteins in the spinal
fluid that can also signal the presence of the disease. Both methods were
equally effective at predicting the disease. After adding personal
characteristics such as age, sex, race and education to the equation, the
researchers further improved their ability to predict who would develop symptoms
The markers that can predict Alzheimer's have been discovered in the last
decade, so researchers needed time to compare their accuracy.
"It just got to that point where we had accumulated enough data," said Catherine
Roe, assistant professor of neurology and lead author on the study. "The reason
that is important is if we're going to be using these biomarkers and one works
better than the other, it helps in deciding which one to use."
The people in the study were cognitively normal when they first enrolled, but
nearly one-third of the participants had signs of Alzheimer's disease on their
brain scans or in their spinal fluid. It's still unknown when they will develop
symptoms, if ever, and when initiating treatment might be most effective.
"If you can administer these treatments when people have abnormal biomarkers,
maybe you can stop Alzheimer's before the person has brain damage," Roe said.
"They are at very high risk for developing dementia symptoms ... it could be the
next time we see (them) or it could be 10 years down the road."
The Food and Drug Administration recently approved measuring biological markers
in people who are already experiencing symptoms of dementia. The measurements
are intended to help doctors determine whether the dementia is from Alzheimer's
or another cause. The university already hosts clinical drug trials as part of
the research into early treatment for people who are genetically predisposed to
But the tests to predict Alzheimer's are not a routine part of health care.
Brain scans are expensive -- patients get liquid placed in their arm that
travels to the brain, clings to any plaques and lights up on a scan. Collecting
spinal fluid through an epidural is less expensive but still carries risk. More
research is needed on the value of the tests.
"Your chances are higher if you have these abnormal biomarkers, but we haven't
done research long enough to know if everybody with biomarkers is going to get
Alzheimer's disease," Roe said.
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