WEDNESDAY, Aug. 24 (HealthDay News) -- Using an advanced MRI
scan, researchers believe they have found changes in the chemistry
of the brains of people with no cognitive problems that signal who
is at future risk for Alzheimer's disease and other dementias.
And although there is no good treatment or cure for the disease,
experts say finding ways to identify those at risk is essential
when treatments and possibly a cure become available.
"We found biochemical changes that correlated with cognitive performance," said lead researcher Dr. Kejal Kantarci, a radiologist at Mayo Clinic in Rochester, Minn. "The better people did on tests that measure cognitive abilities, the fewer changes there were."
These biochemical changes were also associated with other
changes in the brain that are markers for Alzheimer's disease,
Kantarci said that people should not be looking at getting scans
to detect these changes. "We are just at the early stages of
identifying markers," she stressed.
However, finding these biomarkers is important, Kantarci added.
"When possibilities for preventive intervention come about, then we
will have a marker which will help us identify those individuals
who would benefit from these preventive interventions," she
The report was published in the Aug. 24 online edition of
For the study, Kantarci's group used a technique called proton
magnetic resonance spectroscopy to see if they could identify
changes in brain chemistry in 311 men and women in their 70s and
80s who had no apparent cognitive problems.
The participants also underwent PET scans to see if there were
any amyloid-beta deposits, or plaques, in the brain. These plaques
are the first signs of Alzheimer's disease, the researchers
In addition, participants took tests that evaluated memory,
language and other skills.
Kantarci's team found that 33 percent of the people had
significantly high levels of amyloid-beta deposits in their brains.
These people also had high levels of two chemicals:
myoinositol/creatine and choline/creatine.
Those with high levels of these so-called brain metabolites also
were more likely to have lower scores on several of the cognitive
tests, regardless of the amount of amyloid-beta deposits in their
brains, the researchers added.
Kantarci said these biochemical changes start years before
people show signs of cognitive problems. Whether these markers are
a cause of dementia or only a signal for other changes isn't known,
she said. "What we are seeing is a marker of a pathological process
rather than a cause," she explained.
Heather M. Snyder, senior associate director of medical &
scientific relations at the Alzheimer's Association, said "there is
a growing body of evidence that biological changes associated with
Alzheimer's disease are occurring maybe even 20 years prior to any
individual having any cognitive issues."
"The goal is that we would like people to live a healthy life as long as possible, so if we can diagnose people with these changes as early as possible, when a treatment is available we can intervene -- that's really our ultimate goal," she said.
That's why finding ways to identify people at risk early is
important while the search for treatments and cures continues,
Identifying people at risk for dementia is also important for
research, said Dr. Marc L. Gordon, a neurologist and Alzheimer's
researcher at The Feinstein Institute for Medical Research in
"It is important to identify people at risk of dementia, particularly if we want to test therapies that have the potential to alter the process to try to prevent people from converting to dementia," he said.
Greg M. Cole, a neuroscientist at the Greater Los Angeles VA
Healthcare System and associate director of the Alzheimer's Disease
Research Center at the University of California Los Angeles David
Geffen School of Medicine, said that "these results show that more
and more specific biochemical changes that presage Alzheimer's
disease can be detected in our normal aging population using
sophisticated imaging technology."
But, Cole added, "The question now is whether we can find a way
to intervene in people where these very early steps in the disease
process are measurable by suppressing the pathological process
until we normalize the disease indices and show that they don't go
on to develop dementia."
For more on Alzheimer's disease, visit the
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