Can measuring electrical activity in the brain help identify brain changes linked to Alzheimer’s?
Sylvain Baillet, Ph.D.
In Alzheimer’s, the proteins beta-amyloid and tau accumulate to form plaques and tangles respectively, two hallmark brain changes observed in the disease. Recent studies suggest that these brain changes associated with Alzheimer’s appear decades before the clinical symptoms, including changes in memory. Scientists, therefore, are looking for ways to measure tau and amyloid levels in the brain long before clinical symptoms become evident. One tool for measuring tau and amyloid in living brains is a scanning technique called PET (positron emission tomography). However, PET procedures are expensive and invasive.
Dr. Sylvain Baillet and colleagues have developed an alternate method of measuring tau and beta-amyloid in the brain. This technique uses magnetic resonance imaging (MRI) imaging, which visualize the brain’s structure, and magnetoencephalography (MEG) scans, which visualize the brain's electrical activity. They found that when combining data from these two types of pictures, the research team was able to measure amyloid and tau levels in the brain as effectively as they could with the more invasive PET procedures in their study population.
Dr. Baillet and team will now conduct a larger study of this technique. They will recruit and test several hundred older adults who have no cognitive impairment, have a family history of Alzheimer’s, and have agreed to participate in PREVENT-AD (a large study of aging in Canada). All individuals will have received MRI, MEG and PET scans before enrollment. They will measure levels of beta-amyloid and tau in the participants with both the traditional PET scan method and their own combination of MEG and MRI method. They will then compare how accurately the two methods achieve these measurements in this population, and how well they reveal protein-related changes in brain activity. Next, Dr. Baillet and colleagues will compare how well the two methods can track changes in disease-related brain changes over time by analyzing follow-up MEG recordings and PET scans. Lastly, the investigators will use results from cognitive tests administered over time to compare how the protein changes measured by PET or MEG/MRI relate to cognitive decline in the individuals.
Dr. Baillet’s project could identify a safe, non-invasive and cost-effective method for detecting brain changes linked to dementia. This method could also be used to help diagnose dementia at an early stage.
This Project has been made possible by the Canada Brain Research Fund (CBRF), an innovative arrangement between the Government of Canada (through Health Canada) and Brain Canada Foundation, and of the Alzheimer’s Association.
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