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Brain Scans May Help Predict Alzheimer's Disease
ST. PAUL, MN (June 22, 1998) -- Brain scans of elderly patients with memory problems helped researchers identify those at risk for developing Alzheimer's disease, according to a study published in the June issue of Neurology, the scientific journal of the American Academy of Neurology.
Brain activity was measured by using a scan technique known as single photon emission computed tomography (SPECT). Researchers injected patients with a material that circulated throughout the brain. In areas of the brain where information is most actively processed, the material lodged briefly and a scan was taken. The scan identified patterns of brain activity.
By identifying abnormalities in brain activity, researchers correctly predicted 83 percent of the time who would develop Alzheimer's disease within two to three years. In these patients, brain scans showed four regions of the brain that processed information slower than in their healthy counterparts. Three of the four affected regions control memory functions. These regions in the brain are damaged within the early stages of Alzheimer's disease according to autopsy studies.
"The information that SPECT provides can be a significant improvement over other prediction methods such as neuropsychological testing," said neurologist Keith A. Johnson, MD, of Brigham and Women's Hospital in Boston, who conducted the study. "This study is exciting and potentially valuable, but the methods must be tested further before they are available for patients."
Initially, researchers examined 152 adults with no memory loss to establish normal patterns of brain activity. Researchers then examined 136 other adults, and evaluated them annually for a minimum of two years. These adults, with an average age of 74, were divided into three groups.
One group consisted of 35 elderly people with no memory loss. Another group had 56 people with Alzheimer's disease at the start of the study. The remaining 45 people had a "questionable" risk of developing Alzheimer's, according an Alzheimer's rating system.
The rating system examined their abilities in areas such as memory, problem solving and performing daily activities. The rating system itself cannot identify those who will later develop Alzheimer's disease, according to Johnson. In the follow-up period, 18 of the 45 questionable people developed Alzheimer's disease. "Finding objective ways to predict Alzheimer's disease becomes more important as treatments for early Alzheimer's continue to advance," said Johnson. "Without objective testing methods it's difficult to differentiate between normal aging signs and early Alzheimer's disease."
Research is supported by grants from the National Institute on Aging and the National Institutes of Health.
Alzheimer's disease is a progressive, degenerative disease that destroys brain cells. Alzheimer's disease affects approximately 25 to 30 percent of elderly adults.
The American Academy of Neurology, an association of more than 15,000 neurologists and neuroscience professionals, is celebrating its 50th year of improving patient care through education and research.
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