Alzheimer's disease is being redefined for the first time in 27 years, with new medical guidelines reflecting the fact that the disease is a "continuum." Growing evidence shows that Alzheimer's starts affecting the brain years before dementia symptoms present themselves, and the new guidelines reflect that by dividing the disease into three stages: end-stage dementia, a middle phase involving mild problems, and a symptomless beginning stage where the brain has already begun to change.
"I think we’re going to start to identify it earlier and earlier," says one expert. The new guidelines are concerned with measuring biomarkers, or indicators that a person will likely develop dementia, in clinical trial patients, the New York Times reports. The Wall Street Journal notes that earlier diagnosis of the disease will also allow earlier intervention, and could someday allow patients to take Alzheimer's-slowing drugs earlier. (Read more Alzheimer's diagnosis stories.)