Dr. Jacques Montplaisir

Every 90 minutes, during periods of sleep marked by rapid eye movements (REM), most people lie paralyzed, breathing and dreaming. As we age, though, some of us lose that paralysis during REM sleep and begin to act out our dreams – sometimes violently.

At the Université de Montréal, Dr. Jacques Montplaisir, a psychiatrist and neurobiologist, is investigating the association between REM sleep behaviour disorders and Parkinson’s disease. The vast majority of people with the sleep disorder (about one per cent of the general population) go on to develop either Parkinson’s disease or dementia with Lewy bodies, another progressive neurological disease closely associated with Parkinson’s. This work is being funded by a one-year, $44,850 Pilot Project Grant from the Parkinson Canada Research Program, supported by the Quebec Research Fund* on Parkinson of Parkinson Quebec.

“Up to 80 per cent of these sleep behaviour disorder patients will develop Parkinson’s disease or dementia with Lewy bodies within the timeframe of about 10 years,” says Montplaisir. “It’s a very important risk factor for Parkinson’s disease.”

Using Positron Emission Tomography (PET), Montplaisir and his team will scan the brains and guts of people with the sleep disorder to look for the abnormal transmission of a chemical called acetylcholine. They believe that people with the sleep disorder have a defect that is preventing them from transmitting enough of the chemical.

By comparing their scans with scans of people who don’t have Parkinson’s disease, Montplaisir and his colleagues hope to find PET scan markers in the brain that will indicate a population of people most likely to develop Parkinson’s.

Identifying a population of people 10 or 20 years before they develop the motor control symptoms most commonly associated with Parkinson’s would give researchers a chance to administer new drugs that could slow or stop the degeneration of brain cells that occur before most of the damage to the brain has been done, Montplaisir says.

“There are (new) drugs that are coming. We would like to have access to these medications to treat patients with REM behaviour disorder,” he says.

Montplaisir has been conducting research into sleep disorders for decades, not knowing his work would lead to a connection with Parkinson’s disease. Now, he feels on the cusp of “a major breakthrough” that will lead to a better understanding of the disease.

Read about other researchers recently funded by the Parkinson Canada Research Program.

*Quebec Research Fund on Parkinson is funded notably, by the Saucier-van Berkom Parkinson Quebec Research Fund.