A new study suggests that brain imaging may detect changes linked to Alzheimer’s disease more than seven years before amyloid plaques become visible on standard scans. Led by researchers in the Department of Psychology at the University of Oslo, the study was published in Nature Neuroscience.
The findings indicate that amyloid positron emission tomography (amyloid PET), currently considered the gold standard for Alzheimer’s disease imaging, may not detect all of the earliest changes occurring in the brain. Researchers identified structural brain changes at least seven years before amyloid plaques could be seen on PET scans.
“We discovered that structural changes in the brain occur years before high levels of plaque are seen on PET scans, the brain scans currently used to identify early signs of Alzheimer’s disease,” says James-Michael Roe.
At the time of the study, Roe was a postdoctoral researcher at the Center for Lifespan Changes in Brain and Cognition (LCBC) at the University of Oslo’s Department of Psychology. He now serves as International Scientific Director at Cercare Medical. Roe led the study while working at LCBC.
Early brain changes may improve Alzheimer’s detection
The results suggest that Alzheimer’s-related processes may begin in the brain long before they can be detected using today’s most advanced imaging techniques.
“We have discovered the earliest signal ever detected in a brain scan. This could help us track the disease before symptoms appear and aid in early detection,” Roe says.
To identify these early changes, researchers followed healthy adults who received regular magnetic resonance imaging (MRI) scans over nearly 20 years. This long-term data allowed the team to determine when amyloid plaques first became detectable and which participants eventually developed them.
The researchers then analyzed MRI scans collected during the previous 10 years. They compared changes in brain structure among people who later developed amyloid plaques with changes in participants who did not.
“The most groundbreaking aspect of this study is that we discovered structural changes in the brain years before the first signs of plaque buildup, which are considered early signs of Alzheimer’s disease, appear,” says Anders Martin Fell, professor of psychology and director of the LCBC.
“These are older adults with good cognitive function. What is unique here is that we examined changes in brain structure over the years before plaques were revealed on the first scan,” Fell says.
Rethinking the earliest stages of Alzheimer’s disease
Fell notes that Alzheimer’s disease remains difficult to treat because it is closely linked to aging and is likely influenced by multiple biological processes.
“These findings suggest that changes in the brain precede the first detectable signs of amyloid plaque accumulation. This is considered an early stage of the disease and occurs years before cognitive symptoms begin to appear,” he says.
Fell says there are two possible explanations for the findings:
1. Although amyloid plaques cannot yet be detected on brain scans, harmful processes that contribute to or result from plaque buildup may already be active in the brain.
or
2. Other biological processes may cause structural brain changes before amyloid plaques begin to accumulate.
Potential impact on Alzheimer’s disease treatment
The second possibility could have important implications for the development of future Alzheimer’s treatments. If early brain changes begin through mechanisms other than amyloid plaque accumulation, researchers may need to continue developing therapies that target additional biological processes.
“If the latter is true, it suggests that it is important to continue developing drugs that target processes other than amyloid plaque accumulation. However, this requires further research,” Fell says.
Source: www.sciencedaily.com