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USF experts develop a way to measure part of the brain that shrinks years before the disease is evident.
By LEONORA LaPETER
© St. Petersburg Times, published May 28, 2002
Alzheimer's disease can lurk in the brain for decades before revealing the tell-tale loss of memory, reason, personality and eventually, life.
Now researchers believe MRI scans of the brain can be used to predict if someone will get Alzheimer's decades before the first symptoms show up and damage already has been done. The scans work by measuring the size of the hippocampus, an area of the brain associated with memory that is believed to shrink over time as Alzheimer's progresses.
The findings by researchers at the University of South Florida and the University of Kentucky were published today in the journal Neurology.
"The reason it's important is that if the disease is going on behind the scenes, every year or two that passes, more damage is being done," said Dr. James Mortimer, director of the USF Institute on Aging and one of the study's co-authors. "If we want to actually stop the disease, we have to get to it early. Everyone in the field agrees that's the case."
Researchers have known for some time that Alzheimer's shrinks the hippocampus, which is roughly the size and shape of a sea horse. The study, which is the doctoral dissertation of former USF student Karen Gosche, found there is a window of time, sometimes decades, between when the hippocampus begins to shrink and the first visible symptoms of Alzheimer's emerge.
Gosche developed a computer program that measures the volume of the hippocampus on MRI scans within a few minutes. These measurements would normally take a half hour or more, essentially restricting their use to research, Mortimer said.
"It's important to know there's a window of opportunity to stop the onset of this disease," said Steve DeKosky, vice chairman of the board of the National Alzheimer's Association and chairman of the department of neurology at the University of Pittsburgh. "If in fact there is shrinkage earlier, there is more normal brain tissue and you can hold on to what you've got a lot easier instead of fighting at the tail end."
The MRI scan and other potential Alzheimer's predictors -- a loss of the sense of smell, possession of a particular gene and the larger dilation of the pupil when drops are placed in it -- could combine to help doctors determine earlier who will get the disease.
Mortimer said drugs are being studied that could be used to combat Alzheimer's, making the scans even more valuable once those drugs reach the market.
But he cautioned that the scans to detect Alzheimer's require further study. The scans probably would not be available for three or four years.
"We don't want to get expert at finding people who have the disease until we can do something about it," he said. "But eventually one possibility is that you might have people screened for the disease using MRI scans. It may sound expensive, but when you compare the cost to people who have the disease, if we find and prevent it, it would be a lot cheaper."
He said the MRI scans could cost as little as $400. But researchers acknowledge that the scans could affect a person's ability to get health and life insurance if the scans indicate the person is likely to get Alzheimer's one day.
"A major issue which will have to be faced is confidentiality," Mortimer said.
The research is based on the study of 56 brains donated by Catholic nuns, who agreed more than a decade ago to donate their brains after they died. Some 678 nuns, ranging in age from 75 to 102, agreed to participate in the study.
Since the nun study began, more than half the women have died and their brains have been shipped to the University of Kentucky for autopsies.
Previous findings from the nun study revealed that women with more education had larger brains.
The researchers also studied autobiographies written in the 1920s by 25 nuns who later got Alzheimer's. They found that 90 percent of those women had poor linguistic skills even as they entered the convent when they were in their 20s.
The average person enters the first stage of Alzheimer's -- when there are no symptoms -- in their mid 40s or early 50s.
Alzheimer's is one of the most common terminal illnesses among the elderly in the industrial world, right behind heart disease and cancer. Nearly 400,000 new cases of Alzheimer's are reported every year. In the United States, some 4-million people suffer from the disease, and some 8.5-million are expected to have it by 2030 if no cure is found.
-- Times researcher Kitty Bennett contributed to this report.