Study finds Alzheimer’s brain changes 7 years before plaques appear

Alzheimer's disease may leave detectable traces in the brain more than seven years before amyloid plaques — long considered the earliest measurable sign of the condition — become visible on PET scans, according to a study published this week in Nature Neuroscience.partner.sciencenorway+1

Researchers at the University of Oslo's Center for Lifespan Changes in Brain and Cognition tracked cognitively healthy older adults with regular MRI scans over nearly two decades. They found that cortical thinning — a measurable reduction in the brain's outer layer — preceded the point at which amyloid plaques became detectable by at least seven years.

"We found the earliest signal detected on brain scans to date, which could be useful for tracking the disease before symptoms emerge and may help with earlier detection," said James Michael Roe, the study's lead author and now International Scientific Lead at Cercare Medical.partner.sciencenorway

What the Finding Means

The discovery challenges the prevailing assumption that amyloid-PET imaging captures the very beginning of Alzheimer's pathology. Anders Martin Fjell, a professor at the University of Oslo and head of the research center, said the results suggest that either harmful processes linked to plaque accumulation are already underway before plaques become scannable, or that entirely separate processes are driving early brain changes.partner.sciencenorway+1

"If the latter is true, it suggests it is important to continue developing drugs that target processes other than amyloid plaque accumulation," Fjell said.news-medical

GLP-1 Drugs: A Parallel Search for Treatments

The study arrives as researchers continue exploring alternative approaches to Alzheimer's treatment, including GLP-1 receptor agonists better known for diabetes and weight management. A clinical trial led by Imperial College London found liraglutide could reduce cognitive decline by as much as 18 percent over one year in patients with Alzheimer's.iflscience

However, Novo Nordisk's ↗ 1.85% larger evoke and evoke+ trials — enrolling 3,800 participants on oral semaglutide — concluded the drug "was not efficacious in slowing clinical progression in participants with early Alzheimer's disease". Researchers have suggested the oral formulation may simply fail to reach the brain in sufficient quantities, rather than invalidating GLP-1 drugs as a class.iflscience

The Road Ahead

Together, the Oslo findings and ongoing drug research underscore a central tension in Alzheimer's science: the disease begins quietly, years before current tools detect it or treatments can intervene. Whether earlier structural imaging or novel drug classes can narrow that gap remains an open question — one Fjell acknowledged requires further study.partner.sciencenorway+1