PORTLAND, Ore. -- For years scientists have been trying to stop Alzheimer's disease in those who already have been diagnosed. Now the first major study to investigate the possibility of preventing the disease in the oldest old is under way at Oregon Health Sciences University. Researchers in OHSU's Oregon Aging and Alzheimer's Disease Center, or OAADC, and the OHSU's Oregon Center for Complementary and Alternative Medicine in Neurological Disorders, or ORCCAMIND, are investigating the suggested benefits of the herbal remedy ginkgo biloba. Specifically, scientists would like to determine whether the herb could delay or prevent the early stages of Alzheimer's disease in older people. The research is funded by the National Center for Complementary and Alternative Medicine.
Currently ginkgo biloba is used around the world by alternative and complementary health providers who believe it improves cognitive function. In the United States alone, Americans spent $240 million on ginkgo biloba in 1997. While numerous clinical trials have investigated the possible cognitive benefits of the plant extract, only a small percentage of these studies were properly randomized, blinded, and used modern standards for diagnosis and assessment.
During OHSU's four-year study, researchers will focus on people 85 years and older. This group was chosen because they have the highest risk for developing mild cognitive impairment, a precursor to Alzheimer's disease. The scientists are looking for a total of 200 subjects who do not display signs of mental impairment. Each volunteer will receive regular checkups. Written and verbal tests will be used to determine whether there has been any significant cognitive degeneration during the span of the clinical trial. In addition, MRI testing will help detect changes in brain structure.
"People across the country and around the world believe that taking ginkgo biloba can aid in mental function and slow or prevent the onset of Alzheimer's," said Jeffrey Kaye, M.D., director of OAADC at OHSU and principal investigator of the study. "Right now we're trying to determine whether it works. We also want to know if this popular supplement could benefit the oldest portion of our population, the segment most likely to develop cognitive impairment."
"To many people, taking a natural substance such as ginkgo biloba to treat or prevent memory loss seems to be a safe thing to do. But the fact is, we need to recruit a group of older people who will participate in this clinical trial in order to understand the benefits and risks of ginkgo for persons who may develop mild cognitive impairment," said Neil Buckholtz, Ph.D., chief of the Dementias Branch at the National Institute on Aging.
This study begins as the country observes National Alzheimer's Awareness Month. Approximately 4 million Americans have Alzheimer’s disease. One in 10 people 65 and older, and nearly half of those age 85 and older have Alzheimer’s.
OHSU’s clinical trial is one of the initial research projects of ORCCAMIND, a research center at OHSU focusing on alternative therapies for neurological disorders. The center was founded in 1999 through a $7.8 million dollar grant awarded by the National Center for Complementary and Alternative Medicine, a component of the National Institutes of Health.