Earlier Brain Changes May Signal Alzheimer’s Disease
A study led by researchers at the University of Oslo suggests that measurable changes in brain structure may emerge more than seven years before amyloid plaques become visible through PET imaging, currently considered a leading method for identifying early signs of Alzheimer’s disease. The findings were published in Nature Neuroscience.
Researchers followed healthy, cognitively functioning older adults who received regular MRI scans for nearly 20 years. This long-term dataset allowed the team to identify participants who eventually developed detectable amyloid plaques and then review brain scans collected during the preceding decade. Comparisons with participants who did not develop plaques revealed earlier structural differences.
James Michael Roe, the study’s main researcher, said the results may represent the earliest brain imaging signal identified so far in relation to Alzheimer’s. The findings indicate that disease-related processes may begin before symptoms arise and before amyloid-PET scans can detect substantial plaque buildup.
The researchers outlined two possible explanations. Harmful biological processes associated with plaques may already be underway while remaining below current detection thresholds. Alternatively, separate biological mechanisms may alter brain structure before amyloid accumulation begins.
This distinction could affect future approaches to diagnosis and treatment. If structural changes are driven partly by non-amyloid processes, therapies focused exclusively on reducing amyloid plaques may not address every factor involved in the disease’s earliest stages. However, the researchers emphasized that further investigation is required before the findings can guide clinical practice or drug development.
The study does not establish that these early structural changes cause Alzheimer’s or confirm that all affected individuals will develop cognitive symptoms. Instead, it raises questions about how the disease begins, how early it might be detected, and whether multiple biological pathways should be considered. Long-term studies will be needed to confirm the results and determine their practical value for patients and researchers.