TAMPA, Fla., May 28 (UPI) -- A magnetic resonance imaging or MRI scan of the brain may predict who will develop Alzheimer's disease -- years or even decades before dementia or any other symptoms of the disease appear -- researchers reported Tuesday.
Identifying people at risk of developing Alzheimer's would enable those patients to begin medication that could slow or reverse the disease before it damages the brain, James Mortimer, director of the University of South Florida's Institute on Aging and one of the co-authors of the study, told United Press International.
Currently, there is no blood test or brain scan that can detect Alzheimer's disease, and the diagnosis is made by observing the patient for signs of dementia and memory loss. Whether a person actually has the plaques in the brain characteristic of Alzheimer's is not known until after death and an autopsy is performed.
Mortimer's team scanned the brains of 56 nuns involved in an ongoing study of more than 600 Catholic sisters who have agreed to donate their brains after death.
It was previously known that a region of the brain known as the hippocampus shrinks in people with Alzheimer's but this was thought to occur in the later stages of the disease. Mortimer's research found the hippocampus "appears to shrink very early in the disease before the development of memory loss or dementia," he said.
"Some of the nuns had fully developed Alzheimer's (according to pathological criteria and analysis of the brains) and had no symptoms of the disease when they died," Mortimer said. This means using MRI scans to monitor changes in the hippocampus could be a way to determine who will develop Alzheimer's and who should receive drugs that could prevent the disease.
Drugs halting the progression of the disease currently are not available but pharmaceutical companies are working to find such drugs and there is growing evidence that ibuprofen and other common painkillers may be effective in this regard, Mortimer told UPI.
Some Alzheimer's experts are convinced that a class of drugs known as cholinesterase inhibitors delays the progression of the disease, but others think that the drugs merely mask the symptoms while the disease gets worse, Mortimer said.
Neil Buckholtz, chief of the Dementias of Aging Branch at the National Institute of Aging in Bethesda Md., told UPI three studies are underway to investigate substances that may prevent Alzheimer's in healthy people.
One trial will examine the effects of the drugs Alleve (naproxen) and Celebrex (celecoxib). A second is looking at hormone replacement therapy in women. A third is using the herb gingko biloba.
Although the cause of the hippocampus shrinkage is not known, it appears to be related to the severity of the disease. "The more severe the disease is the more the hippocampus shrinks," Mortimer said.
Another brain investigation technique called a PET scan is also showing promise for predicting who will develop Alzheimer's, Mortimer said, although "the advantage of MRI is that it is relatively cheap compared to ... PET scans, so (MRI) becomes a procedure that can be applied to the general population."
The two imaging techniques might prove even more accurate diagnoses of Alzheimer's if they are combined, Buckholtz said.
He added his agency is putting together a program involving cooperation between the National Institutes of Health, the Food and Drug Administration, pharmaceutical companies and imaging device manufacturers to determine which brain scanning strategies "give the earliest possible indication of changes in the brain so that when there are drugs available we're able to treat those people at risk."
(Reported by UPI Medical & Health Correspondent Steve Mitchell in Washington)