Alzheimer's disease has made headlines this week. In the past, only memory tests were available to detect moderate and advanced stage Alzheimer's disease. There are now methods able to detect the disease up to nine years before it becomes apparent. While Alzheimer's is still uncurable, this early detection may allow potential sufferers to postpone its onset. Researchers are working on developing treatments that may combat newly-detected mild cases of the disease.
Two new brain scan techniques have been used to detect Alzheimer's in advance. One, developed at the New York University Medical center, is a PET scan hooked up to an MRI-linked computer program. This technique tracks glucose metabolism in the hippocampus, the area of the brain associated most closely with memory formation and the first to be affected by Alzheimer's. Reduced metabolic activity signals cognitive problems and an increased risk for Alzheimer's disease. Test subjects in one study of the disease were followed for ten to twenty-four years to track their neurological decline. A second test, piloted at University College London, uses an MRI-type scan that focuses on brain biochemical activity instead of structure. In individuals who carry a gene that predisposes them to Alzheimer's in old age, the scans picked up abnormal levels of two neurochemicals -- N-acetyl aspartate and myo-inositol -- compared to noncarriers, even before they showed any signs of cognitive malfunctioning.
A simple blood test may also be useful for detecting Alzheimer's risk. This test measures levels of harmful amyloid proteins, specifically beta-amyloid 42, which can clump, coat, and kill brain cells if there are not enough antibodies to fight it. High levels of amyloid can double or triple Alzheimer's risk, while the antibodies can decline by some two thirds. The blood tests have been used to track subjects for two to twelve years, and while they are less predictive than the PET and MRI techniques, they are also cheaper, require less machinery, and are easier for physicians to fit into routine examinations.
While 4.5 million Americans currently have Alzheimer's, that number could rise to 14 million by 2050 as the Baby Boomer generation ages. Studies have found that regular exercise, mentally challenging jobs and activities, and higher levels of social interaction correlate to lower risk of the disease. It has not yet been determined, though, whether lower social activity is caused by the presence of Alzheimer's or if less interaction contributes to the disease, but in either case this type of activity is agreed to be mentally stimulating.
A few experimental therapies have been developed that could prevent amyloid buildup. One medication, called Flurizan, is in late stages of testing and has shown some promise in slowing Alzheimer's, though it seems most effective on milder cases. The second therapy is an intravenous immunoglobulin antibody cocktail that may act as a sponge and suck up extra beta-amyloids. These positive results are still preliminary, based on only a small sample. Another study revealed that insulin delivered intranasally helped early cases of Alzheimer's, since the disease causes insulin to be removed from the brain, drawn into the bloodstream. Delivering insulin through the nose transports it straight to the brain, where it can be used for necessary regulatory processes and improving memory. Therapists in Japan have even developed an exercise program of low-intensity calisthenics and singing, which they say has improved memory in elderly persons with mild cognitive impairment.
If at least one of these treatments proves successful on a larger scale, it would help combat a disease that too often is caught in advanced stages and left to run its inevitably crippling course.
Sara Cuccio is a research intern at the American Council on Science and Health. For added information on Alzheimer's, please see ACSH's 2002 report, written by Dr. Agnes Heinz.
