Tracking brain wave activity in individuals at high risk for Alzheimer’s disease may be a promising new method for early detection, according to a new Canadian study by researchers at Baycrest Centre for Geriatric Care in Toronto, Ontario.
This is possible because brain waves tend to slow down in certain regions likely to be affected by the disease next, even before neurons have been lost.
The findings, published online in the journal Human Brain Mapping, show that individuals potentially in the early stages of Alzheimer’s disease (mild cognitive impairment) and those with a rare form of language dementia (primary progressive aphasia) exhibited sluggish brainwaves and subtle signs of damage in the brain regions responsible for memory and planning.
Although these individuals only displayed minor memory and thinking problems at the time, the slower brainwaves predicted the severity of their condition, such as the degree of memory loss.
“By using brain imaging, we were able to pinpoint that this slowing of electrical activity occurs in specific regions that have not yet lost brain cells, but are negatively affected by the disease,” said Dr. Jed Meltzer, senior author and Canada Research Chair in Interventional Cognitive Neuroscience at Baycrest’s Rotman Research Institute.
“This means that these areas could be more responsive to treatments since the brain cells have not died yet and are only starting to undergo damage.”
These brainwaves may also change in response to interventions, added Meltzer.
“Our work identifies a potential biomarker that indicates when the brain cells start to malfunction and opens the door to implementing targeted brain treatments during earlier stages of neurodegenerative disorders,” said Meltzer, also an assistant professor in psychology and speech-language pathology at the University of Toronto.
Surprisingly, the researchers also discovered that healthy older adults displayed “sped up” brain waves compared to young adults, which is distinctly opposite to the trajectory of older adults with dementia.
“One of the challenges in diagnosing Alzheimer’s disease is differentiating whether changes to the brain’s structure are a part of normal aging or actually early signs of the disorder,” said Meltzer.
“Based on these findings, researchers could potentially use measurements of brainwave activity before and after an intervention to test its effectiveness in a faster and clearer manner.”
For the study, researchers analyzed the brain’s electrical activity and brain structures of 64 adults as they were in a resting-state, not focusing on a task.
Magnetoencephalography (MEG) was used to measure brain waves and pinpoint their specific location, and magnetic resonance imaging (MRI) was used to detect brain cell loss. The participants also completed evaluations designed to test their cognitive abilities.
As a next step, the researchers are exploring the use of brain stimulation as a way to slow the progression of neurodegenerative disorders, including Alzheimer’s disease.