Brain scans may reveal signs of Alzheimer's disease more than seven years before the first amyloid plaques become visible, according to a new study from Norway. Researchers at the University of Oslo followed healthy older adults with repeated MRI scans for nearly two decades, and found structural changes in the brain that predate the current earliest detectable marker of the disease.
A 20-year look back at the brain's silent shifts
The team tracked cognitively normal individuals who underwent regular MRI scans over almost 20 years. By the end of that period, some participants had developed amyloid plaques, the sticky protein clumps that are considered a hallmark of Alzheimer's and are typically spotted using PET scans. The researchers then reviewed the earlier MRI images from those same people, comparing them with scans from participants who never developed plaques.
What they found was a consistent pattern: structural changes in the brain appeared years before the first plaque signal showed up on a PET scan. The study, published in Nature Neuroscience, suggests that the current gold standard for Alzheimer's imaging may not be sensitive enough to catch the earliest disease processes.
A possible new window for early detection
James Michael Roe, the study's lead researcher while at the university's Center for Lifespan Changes in Brain and Cognition, said the results point to disease-related changes happening long before today's most sensitive scans can detect them. He noted that this could be useful for tracking the disease before symptoms emerge.
Anders Martin Fjell, a professor and head of the center, called the finding groundbreaking. He emphasized that the participants were well-functioning older individuals, and that the uniqueness of the study lies in examining brain structure changes in the years before the first plaque appeared.
The discovery does not mean Alzheimer's can be diagnosed earlier yet, but it opens the door to understanding the disease's timeline in a new way. If structural changes precede plaque buildup by years, scientists may need to rethink what counts as the earliest stage of Alzheimer's. For now, the finding offers a potential target for future research into earlier detection and monitoring, though no clinical test is ready based on this work alone.
