July 20--In the long run, diagnosing Alzheimer's before symptoms appear could improve treatment.
"The earlier we can make it, the more effective our treatments can potentially be," said Dr. Kaycee Sink, an associate professor at Wake Forest University Baptist Medical Center and the director of the center's memory assessment clinic.
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The idea is to catch it before irreversible damage is done.
In recent years, researchers have been finding ways to identify signs that the disease is developing in people who show no symptoms by measuring the levels of certain proteins in spinal fluid and by using brain-imaging technology to detect the presence of a protein called amyloid that creates plaque in the brains of people with Alzheimer's.
The more markers that are present, the higher the likelihood that Alzheimer's is developing, said Dr. Geoffrey Dunbar, the senior vice president for clinical development and regulatory affairs and the chief medical officer for Targacept, a local drug-development company.
Dunbar was among those in Hawaii last week for the Alzheimer's Association International Conference on Alzheimer's Disease, where new guidelines were proposed that would put people who tested positive for those spinal-fluid or brain-imaging markers into a new category called pre-clinical. That's in addition to the two already recognized stages -- mild cognitive impairment and Alzheimer's.
The news that serious cognitive deterioration may be on the way years before symptoms appear may be disturbing to, say, a 55-year-old man who is apparently in good health.
It's information that could be wrong. As it is, none of the markers are definitive.
"Parts of this are hypothetical," Dunbar said. And there is always the possibility of a false positive.
An early diagnosis could also open the door to such problems as insurance companies refusing coverage based on tests, Sink said.
At the moment, though, people need not worry about going in for a regular physical and learning that they can expect to have Alzheimer's in 10 years.
"Most of these tools aren't readily available to physicians practicing in the community," Sink said.
Early warning could have benefits, too, Sink said. "You have time to plan. You might make different choices with your life."
The psychological and social issues aside, identifying the disease earlier opens up possibilities for developing drugs that, if used early on, could halt the progress of the disease. As it is, none of the drugs currently available can do that.
"They don't change the fact that brain cells are dying," Sink said.
"We are undertaking trials in patients who are too late in the disease process," Dunbar said.
Targacept is doing research on two drugs related to Alzheimer's but, at the moment, it is not doing research on any drugs that would be targeted at people in the pre-clinical stage, Dunbar said.
There wasn't talk at the conference about such medicines in development by other companies, he said. "What was a little depressing was the lack of new medicines."
Even if drugs are developed that, say, prevent the build-up of amyloid plaques in the brain, that doesn't mean that a single drug could be found to prevent the disease.
"There are other pathologies involved," Sink said. "We will need to come at this from several different approaches."
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