Inside STAT: They have 'Alzheimer's brains' but no symptoms. Why?

PET SCAN RESULTS THAT ARE PART OF A STUDY ON ALZHEIMER'S DISEASE AT GEORGETOWN UNIVERSITY HOSPITAL. (EVAN VUCCI/AP)

For years, the prevailing theory among aging experts was that clumps of protein in the brain — either amyloid plaques or tau tangles — meant that memory and other cognitive function were on the decline. But a select group of elderly individuals had these so-called biological hallmarks of Alzheimer's disease, but showed none of its cognitive symptoms. These people were considered an anomaly, but the public-private partnership known as the Alzheimer’s Disease Neuroimaging Initiative and other large studies have found that individuals with Alzheimer's-like brains but regular cognitive function are far from rare. Researchers are still trying to understand how 30% of older adults seem to have the protein structures, but are somehow protected from their detrimental effects. STAT Plus subscribers can read more from Sharon Begley here.