Parkinson’s disease was first identified in 1817 by British doctor James Parkinson, who described various symptoms of what was then called the “shaking palsy.”
More than 200 years later, there’s still no cure, but researchers are making progress in a number of areas, looking at the causes of the disease, improving patients’ quality of life, and hoping for an eventual cure.
Here’s a look at Parkinson’s disease and what research is currently being done on it.
What is Parkinson’s disease?
Parkinson’s is a chronic, degenerative brain disorder. It’s characterized by a loss of dopamine in the brain, which leads to the appearance of symptoms like a loss of motor control. When the dopamine disappears, the cells can’t function on their own, so they die, according to Marina Joseph of Parkinson Canada.
Parkinson’s disease affects around 100,000 Canadians and roughly 25 people in Canada are diagnosed every day.
What causes it?
The link between dopamine and Parkinson’s has been known since the 1960s, but what causes that underlying dopamine deficiency is still a mystery.
“For a long time, we thought that Parkinson’s was caused by some environmental toxin,” said Dr. David Grimes, an associate professor at the University of Ottawa and director of the Parkinson’s Disease and Movement Disorders Clinic at the Ottawa Hospital.
As such, a lot of research focused on environmental factors. “One of those is pesticides and that’s been fairly clearly shown now,” he said.
A “big breakthrough” came when researchers first identified a gene that caused Parkinson’s, he said. Since then, about eight different genes have been associated with the disease – though genetic factors only account for about one in 10 cases of Parkinson’s.
“For most people that we see, we think the cause of Parkinson’s is a combination of genetic risk factors and some sort of environmental exposure.”
Researchers are still working on identifying the causes, but it’s tough, said Joseph. “Without one single cause, it becomes even more challenging to find one single solution.”
Improving quality of life
Doctors are also making progress on helping patients deal with the symptoms of Parkinson’s, and so, improving their quality of life.
The discovery that people with Parkinson’s had a deficiency of dopamine quickly led to a drug, Levodopa, which has become the “gold standard” of treatment, said Grimes.
“This was really an amazing medical breakthrough,” he said. “Levodopa is the mainstay of treatment for Parkinson’s patients, because your brain takes up the Levodopa and converts it to the dopamine that your brain is missing.”
Although the effect was like a “miracle,” he said, “It’s disappointing that it happened maybe 50 years ago (…) and we’re still using the same treatment as our gold standard.”
Levodopa helps lessen people’s symptoms, but it doesn’t slow the disease’s progress, and it can have side effects. Its effectiveness can also decrease after years of use. There are other medications, but it still remains the primary drug treatment.
One important advancement is the discovery of non-motor Parkinson’s symptoms like depression, REM sleep behaviour disorder, and cognitive impairment – all of which can appear well before the more familiar motor symptoms of Parkinson’s, said Joseph.
Because these symptoms appear sooner, they can help identify someone who might be developing Parkinson’s and can help treat them before things get worse. Even exercise can make a major difference, she said.
Stopping or reversing the disease
Neither Joseph nor Grimes wants to estimate how far away researchers are from a cure, though they’re both hopeful.
“I think people can have a lot of excitement and realistic hope that we are coming up with better therapies. We are understanding the disease better. And I think that there is a real excitement about being able to come up with treatments that truly have an effect on the disease,” said Grimes.
Right now, he says researchers are focusing on a few different areas. Some are looking at the role of a protein that’s present in high levels in the brains of people with Parkinson’s and is thought to contribute to some symptoms. “The hope is that by getting rid of this toxic protein that we then have an effect on the Parkinson’s progression itself,” he said.
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Other people are trying to identify “biomarkers” – ways to diagnose the disease or measure its progression. The hope is that this could help improve treatment options.
Other researchers are investigating the role that genes play in Parkinson’s disease. They’re figuring out the “pathways” through which the genes cause the disease and ways to disrupt them. “People are starting to put together the pieces of the puzzle,” said Grimes.
EDITOR’S NOTE: An earlier version of this story incorrectly identified Marina Joseph. We regret the error.