Changes before plaques appear
Structural changes in the brain can be seen on MRI scans at least seven years before the amyloid plaques linked to Alzheimer's disease become detectable, according to a study published in Nature Neuroscience. Researchers used longitudinal MRI data from cognitively healthy older adults and compared the scans with amyloid-PET results. They found that a thickening of the cortex preceded high amyloid levels by seven years or more.
The paper was led by James M. Roe and colleagues, and the finding was reported in the 1 October issue of Science News. The pattern appeared across repeated scans of the same people, which makes it harder to explain away as a one-off variation between individuals.
What it means for diagnosis
Amyloid plaques have long been treated as a central marker of Alzheimer's disease, and most recent drug approvals target them. The new finding suggests other processes are already under way before plaques build up. Study authors say the result supports continued work on treatments that act on mechanisms other than amyloid, while stressing that more research is needed to confirm the pattern.
If the changes hold up in larger groups, doctors could one day use routine scans to flag people at higher risk earlier, when interventions may have more room to work. MRI is widely available and far cheaper than amyloid-PET, which matters for any screening programme. Researchers caution that the study does not show the changes cause the disease, only that they appear first.
A broader shift in testing
The work fits a wider move toward earlier detection in Alzheimer's research. Blood tests for amyloid and tau are being assessed for use in clinics, and imaging studies continue to map changes that appear years before symptoms. Earlier detection also raises practical questions about what patients and health systems should do with a positive result when treatment options remain limited and expensive.