Simon Fraser University researchers are using a new approach to brain imaging that could improve how drugs are prescribed to treat Parkinson’s disease.
The new study, published in the journal Movement Disorders, looks at why levodopa – the main drug used in dopamine replacement therapy – is sometimes less effective in patients.
The drug is typically prescribed to help reduce the movement symptoms associated with the neurodegenerative disorder.
While it is effective in improving symptoms for the vast majority of patients, not everyone experiences the same level of benefit.
In order to find out why this is the case, an SFU collaboration with researchers in Sweden has used magnetoencephalography (MEG) technology to determine how the drug affects signals in the brain.
“Parkinson’s is the second most prevalent neurodegenerative disease worldwide and it is the most rapidly increasing, in terms of incidence,” says Alex Wiesman, assistant professor in biomedical physiology and kinesiology at SFU.
“Treating this disease, both in terms of helping people with their symptoms, but also trying to find ways to reverse the effects, is becoming more and more important.
“If clinicians can see how levodopa activates certain parts of the brain in a patient, it can help to inform a more personalised approach to treatment.”
The study was a collaboration with researchers at Karolinska Institute in Sweden, who used MEG to collect data from 17 patients with Parkinson’s disease – a relatively small sample size.
Researchers mapped participants’ brain signals before and after taking the drug, in order to see how and where the drug impacted brain activity.
MEG is an advanced non-invasive technology that measures the magnetic fields produced by the brain’s electrical signals.
It can help clinicians and researchers to study brain disorders and diseases, including brain injuries, tumors, epilepsy, autism, mental illness and more.
Using this rare brain imaging technology, Wiesman and team developed a new analysis that lets them “search” the brain for off-target drug effects.
“With this new way of analyzing brain imaging data, we can track in real time whether or not the drug is affecting the right brain regions and helping patients to manage their symptoms,” says Wiesman.
“What we found was that there’s sometimes ‘off target’ effects of the drug. In other words, we could see the drug activating brain regions we don’t want to be activating and that’s getting in the way of the helpful effects.
“We found that those people who showed ‘off target’ effects are still being helped by the drug, but not to the same extent as others.”
Parkinson’s disease is a neurodegenerative disorder, meaning parts of the brain become progressively damaged over time. It affects predominately the dopamine-producing neurons in a specific area of the brain called the substantia nigra.
People with Parkinson’s disease may experience a range of movement-related symptoms, such as tremors, slow movement, stiffness and balance problems.
Wiesman hopes that a better understanding of how levodopa affects an individual’s brain signals could improve how drugs are prescribed to treat Parkinson’s.
“This might be really helpful for tracking individualized responses to these types of drugs and helping with prescribing and therapeutics,” he says.
“So maybe we try different medications, maybe we adjust dosages differently. And this helps clinicians get at that question of how we prescribe personalized medicine in a way that really helps the patient.
“The more we can personalize that approach, make it more expedient, make it a bit more specific to that person, the better.”
This new type of brain imaging analysis is not only for studying Parkinson’s disease; any medications that affect brain signaling can be studied using the method developed by Wiesman and colleagues.
SFU’s ImageTech Lab, at the Surrey Memorial Hospital, is home to the only MEG in western Canada.
“We have this really fantastic technology right here at SFU, and combined with the new analysis approaches that we’re developing, it gives us a really unprecedented look into what’s happening in the brain,” says Wiesman.
“We can use this technology moving forward to study Parkinson’s disease in ways that no one has ever done before worldwide.
“Our next step is to take our new approach and apply it to a larger patient group. We also need to translate this research to more accessible brain imaging methods, like electroencephalogram (EEG).
“Ultimately, we want to make sure this technology is useful for a diverse population and more widely accessible to patients with Parkinson’s disease.”