Alzheimer’s may leave a mark on the brain long before plaques appear

Brain changes associated with Alzheimer’s may begin at least seven years before amyloid plaques become detectable with current PET scans. Researchers uncovered the signal by tracking healthy older adults with repeated brain imaging over nearly 20 years. The discovery could help scientists identify Alzheimer’s earlier and suggests that important disease processes may start before visible plaque buildup.

Alzheimer’s may leave a mark on the brain long before plaques appear. The work was led by scientists in the Department of Psychology at the University of Oslo and was published in Nature Neuroscience. The study suggests that the current gold standard for Alzheimer’s imaging (amyloid-PET) may not be sensitive enough to capture some of the earliest brain changes associated with the disease.

These include processes related to the buildup of amyloid plaques. The researchers identified structural changes in the brain at least seven years before plaques became visible on scans. "We found that structural changes in the brain occur many years before high levels of plaque are seen on PET scans, which is the brain scan currently used to identify the earliest signs of Alzheimer’s disease," says James Michael Roe.