Using electrical activity in the brain to overcome freezing

Assistant Professor Caroline Paquette
Assistant Professor Caroline Paquette

Although most of us take it for granted, turning while we walk is a complicated job. Our brains must calculate where to place our feet, and how to adjust and maintain our balance when we shift direction – all in a split second.

For some people with Parkinson’s disease, turning often results in freezing. Without warning, they find themselves rooted in place. They cannot simply will themselves to move forward.

At McGill University, Caroline Paquette, an assistant professor in the Department of Kinesiology and Physical Education, is trying to determine what regions of the brain are affected in people with Parkinson’s disease who experience freezing. She’s using Positron Emission Tomography (PET) to scan the brains of people with Parkinson’s after they have walked through a series of obstacles that require turns. Her research is being funded by a two-year, $90,000 New Investigator Award from the Parkinson Canada Research Program.

“We know that turning is complex walking, and it’s a huge trigger for freezing,” Paquette says. “It’s quite a big problem in people with Parkinson’s disease, because if your mobility is affected, it affects your quality of life and independence.”

To discover how to overcome freezing, Paquette must first understand what mechanisms in the brain are involved. Before the people in her study begin walking, Paquette and her team inject them with a small radioactive tracer. After they have completed their walking and turning task, technicians scan their brains to see what areas the tracer has lit up, indicating increased activity.

By studying those brain scans of people with Parkinson’s who freeze while walking, as well as the scans of people with Parkinson’s who are not affected by freezing, and comparing those images to scans from people without Parkinson’s disease, Paquette hopes to identify the specific areas of the brain that turning activates.

Paquette will then use another non-invasive technology, called Transcranial Magnetic Stimulation, to stimulate those areas of the brain that seem under-utilized in people who are experiencing freezing.

Coupling TMS, which involves using magnets to create electrical activity in the brain, with current rehabilitation regimes might reduce or eliminate freezing, Paquette believes.

Rehabilitation is already somewhat effective in reducing incidents of freezing, Paquette noted.

“With training, we know that you can get people to have fewer debilitating freezing events, to use other cues on their own and to rely less on the environment. If you are able to use Transcranial Magnetic Stimulation on top of that you could get results faster and maybe have longer-lasting effects,” Paquette says.

If Paquette can prove her theory, her research would open up new areas of treatment and reduce the isolation, anxiety and fear of falling that plague those people with Parkinson’s disease who never know when they will find themselves stuck and unable to move.

For Paquette, this Parkinson Canada grant comes at a critical time because the study will help launch her reputation and her research.

“This is the key for me to build the basis for my lab and my research program so we can get funding to make better treatment interventions available for people with Parkinson’s disease, to improve their mobility.” Paquette says.

Read about other researchers recently funded by the Parkinson Canada Research Program by visiting the research section of www.parkinson.ca.

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