Plaques in the brains diagnosed after someone -- who may have been cognitively unimpaired right up until death -- has been the definitive way to diagnose Alzheimers.
"According to the proposed guidelines, patients who have memory problems caused by the disease will be diagnosed with Alzheimer's dementia, or in milder cases, mild cognitive impairment (MCI) due to Alzheimer's dementia.
The term Alzheimer's disease will be used to refer to the underlying changes in the pathology, Phelps said."
"The proposed guidelines offer much more detail about how to test people's brains at autopsy, specifying tests that should be done and asking pathologists to quantify the amount of plaque in the brain."
It looks like maybe they'll be mapping the location of plaques as well? The article is not completely clear. If the guidelines are adopted and implemented, perhaps we'll get a little clarity.