Scan May Predict Alzheimer's
But it's costly and, without a cure, may not be wanted
THURSDAY, Sept. 13, 2001 (HealthDayNews) -- Looking at sophisticated images of your brain someday may allow doctors to predict whether your future includes Alzheimer's disease. But for now, mass testing would be too expensive, and further, people may not want to know they're in line for a disease that has no cure.
Using a special type of PET scan, researchers from the New York University (NYU) School of Medicine discovered that part of the brain dealing with memory stopped working properly in people who were later diagnosed with either mild cognitive impairment or Alzheimer's disease.
"We conducted a longitudinal study using PET scans to measure glucose metabolism in the brain," says Dr. Mony de Leon, professor of psychiatry and director of the NYU School of Medicine Center for Brain Health. Glucose, or blood sugar, is the body's major source of energy.
The study included 48 healthy men and women, ages 60 to 80. Researchers tested the cognitive abilities and did MRI scans on all participants, then followed up with more tests and scans three years later. The PET scans showed how tissues absorbed glucose; the MRI scans showed physical structures of the body.
At the end of the study, de Leon and his colleagues found that 13 participants had a decline in their mental status. Twelve were diagnosed with mild cognitive impairment, which de Leon says often precedes Alzheimer's disease. One person was diagnosed with Alzheimer's.
The PET scan images showed that one part of the brain was not using as much glucose as other areas. "We observed that among the decliners, there was a reduction in glucose metabolism in the entorhinal cortex, " an area of the brain like a master controller that turns information into memory, says de Leon.
The findings appear in the current issue of the Proceedings of the National Academy of Sciences.
More than 4 million Americans suffer from Alzheimer's disease, and the number is expected to swell to more than 14 million in the next few decades as the population ages, says the Alzheimer's Association. Currently, the only way to definitively diagnose Alzheimer's disease is via an autopsy, says de Leon.
De Leon says the study is just a first step and that people shouldn't rush to their doctor for an Alzheimer's test. A PET scan -- at $1,000 to $3,000 a scan -- is too expensive for mass screening, and researchers say they don't know for sure that people with mild cognitive impairment will go on to develop Alzheimer's. "This is a promising finding, but it still needs further replication," says de Leon.
"This is a very interesting study that suggests you can predict who will have mild cognitive impairment," says Dr. Benjamin Seltzer, professor of neurology and the head of the Alzheimer's Center at Tulane University School of Medicine, New Orleans, La. Even if researchers prove that people with mild cognitive impairment do go on to have Alzheimer's, Seltzer wonders who would want a test to diagnose a disease for which there is no treatment.
What To Do
To read more about mild cognitive impairment, go to Rutgers University.
For more information on Alzheimer's disease, check the National Institute on Aging's Alzheimer's Disease Education and Referral Center.
The Alzheimer's Association describes the warning signs of Alzheimer's.