By Marilynn Marchione, AP Medical Writer
The first new guidelines for diagnosing Alzheimer's disease in nearly 30 years establish earlier stages of the mind-robbing disease, paving the way for spotting and possibly treating these conditions much sooner than they are now.
The change reflects a modern view that Alzheimer's is a spectrum of mental decline, with damage that can start many years before symptoms appear. The new guidance describes three phases: early brain changes, mild cognitive impairment and full-blown Alzheimer's.
Yet the guidelines do not advise doctors to change how they evaluate and treat patients now. Despite the hoopla about new brain scans and blood and spinal fluid tests that claim to show early signs of Alzheimer's, they are not ready for prime time and should remain just tools for research, the guidelines say.
"It's too soon right now" to say these experimental biomarker tests will prove valid enough to be used in ordinary patient care, said Creighton Phelps, Alzheimer's program chief at the National Institute on Aging.
His institute and the Alzheimer's Association convened several expert panels to write the guidelines, the first since 1984. They are being published Tuesday in Alzheimer's & Dementia: The Journal of the Alzheimer's Association.About 5.4 million Americans and more than 26 million people worldwide have Alzheimer's, the most common form of dementia.
"It's likely there are at least as many people with mild cognitive impairment as with Alzheimer's disease and maybe more," said William Thies, the Alzheimer's Association scientific director.
Even before this mild cognitive impairment shows up, brain changes such as a buildup of sticky plaque or protein tangles inside nerves can suggest trouble ahead.
Marilyn Albert, a Johns Hopkins University researcher who led the mild cognitive impairment panel, described this category as "people who have mild, progressive symptoms, changes in mental abilities, usually memory but not always memory" that stop short of full-blown dementia.