What's the problem?
There is no objective test for Parkinson’s disease, which makes it difficult to prove that new treatments are working.
Chris Hudson was approaching mid-life when he noticed a tremor in his hands.
At the time, he had all the trappings of success: he was a respected scholar, married with an eight-year-old son and a daughter, six.
But the newly appointed professor in Waterloo’s Faculty of Science was noticing changes in his body. His muscles were becoming rigid. He was having a hard time sleeping. He could no longer throw a ball well in games with his children. It sounded like Parkinson’s disease but he was only 40 years old. He had a brilliant career ahead of him and a family to support.
It couldn’t be.
Fifteen years later, Hudson, a professor in the School of Optometry and Vision Science, has boxing gloves on and he is calling out punches against a heavy bag, putting all his energy into the fourth punch: “One, two, three, HUH!.”
From the laboratory to the boxing ring
Although most of his life has been devoted to the rigours of the mind, these days he’s being put through the training paces of a boxer because right now, he’s in a fight, both professionally and personally, against Parkinson’s disease — a foe much bigger than a heavyweight champion.
Hudson was eventually diagnosed with young-onset Parkinson’s disease, the same neurodegenerative condition that afflicts actor Michael J. Fox.
The Rock Steady Boxing program for people with Parkinson’s disease that he’s attending at the A.R. Kaufman Family YMCA in Kitchener is part and parcel of Hudson’s personal effort to push back against the devastating condition.
Hudson’s research is also part of that fight. Parkinson’s is a disease for which there is currently no objective test, making it hard for drug companies to evaluate any new discoveries. Hudson hopes to change that. As a co-leader of the ocular research platform, one of several investigational aspects of the much larger Ontario Neurodegenerative Disease Research Initiative (ONDRI), Hudson is researching how to use the eyes as windows into the early detection of Parkinson’s and other neurodegenerative diseases.
Hudson clearly remembers the day he got his diagnosis. It was a shock even though, from his symptoms, he had begun to suspect it. “I have lots of medical friends and they were all telling me, ‘No, you’re too young for Parkinson’s.’”
“You go through all the stages, like denial and anger, and then you finally have to accept it,” he says.
Early-onset Parkinson’s disease can show up before 50
Although the disease is commonly associated with adults over the age of 60, there is a subsection — the young-onset form — that will show up when people are in their 20s, 30s and 40s.
Parkinson’s is a degenerative disorder of the central nervous system. The symptoms come about as a result of cell death in the neurons that secrete dopamine, a neurotransmitter that is a central drive-train for the brain. The basal ganglia structure in the brain controls movement and relies on dopamine to transmit signals. When there is not enough dopamine, movement is delayed or unco-ordinated. Also, the non-motor symptoms of Parkinson’s, such as sleep disturbance and depression, can be just as daunting as the loss of movement and co-ordination.
The condition is more common than people think, and it is on the rise. An estimated 100,000 Canadians have Parkinson’s and more than 25 people a day are being newly diagnosed, according to Parkinson’s Canada. About 20 per cent of the people diagnosed are younger than 50. Parkinson Canada estimates that by 2031, nearly 164,000 Canadians will be living with this disease.
“As time went on, I became more motivated to get involved in the Parkinson’s research, and of course, I also have a self-motivation in that area.”
Chris Hudson, professor in the School of Optometry and Vision Science
After spending some time at home recovering from a serious shoulder injury as well as coming to terms with Parkinson’s, Hudson joined the ONDRI team to lead the ocular aspects of wide-ranging research into neurodegenerative diseases, including Parkinson’s, Alzheimer’s, mild cognitive impairment, dementia and impairment from strokes.
“As time went on, I became more motivated to get involved in the Parkinson’s research, and of course, I also have a self-motivation in that area,” Hudson says. Being able to make a contribution to developing an objective test for a disease that he personally is grappling with is “quite therapeutic for me,” he adds.
The lack of an objective test is a huge problem in terms of the development of new drugs because Parkinson’s can proceed in markedly different ways for people. Without a way of measuring it, it’s hard for pharmaceutical companies to prove that a new treatment is really working. “It’s hard to evaluate any new treatment, and that is limiting for the development,” Hudson says.
The eye can be a measure of brain health
Hudson is hoping the eyes can provide that objective test. He’s looking at changes in the thickness of the retina at the back of the eye, which can be an indicator of the changes happening in the brain.
“The idea is that the death of cells in the brain has a retrograde effect on the visual pathways and the nerve cells that carry visual information, and that causes neurodegeneration in the retina," Hudson says. What’s happening in the retina can be a “surrogate measure of brain health.”
Hudson’s research is collected with an instrument that uses a technique called spectral domain optical coherence tomography. It is basically a laser camera that provides excellent resolution and can map the changes going on in the retina at an extremely detailed level.
This isn’t the only research that uses eyes as windows into the brain. There has also been Alzheimer’s disease research on detecting the amyloid beta protein in the retina – the same protein that forms the plaques implicated in Alzheimer’s.
Melanie Campbell, professor in the Department of Physics and Astronomy
Melanie Campbell, a professor in the Department of Physics and Astronomy and the School of Optometry and Vision Science at the University of Waterloo, leads a team that is developing an instrument that will use polarized light to detect those amyloid deposits in the retina at the rear of the eye.
“We can see these amyloid deposits by looking at their interaction with polarized light. We can do clever things with the polarized light to make them show up so that they look like bright spots against a darker background. We can do that without using a dye or any other invasive procedure,” Campbell says.
Eyes may also show early evidence of Alzheimer’s disease
The amyloid deposits detected in these images can be an early biomarker of Alzheimer’s disease. There is no cure for Alzheimer’s but if there were a way of detecting it early, it’s possible to start on a regime that might delay some of the symptoms and give the individual a better quality of life for more years. “The earlier diagnosis also allows the patient to be involved in the decisions around their care while they still have that decision-making ability,” Campbell adds.
Currently, the only way of definitively seeing Alzheimer’s amyloid plaques is by examining the brain in an autopsy after death. An expensive PET amyloid brain scan is used in studies of the disease but not for routine diagnosis. While the person is living, doctors can only say that the person has probable Alzheimer’s, based on the symptoms of cognitive decline and the results of cognitive testing.
But amyloid deposits are known to build up in the brain for 10 to 15 years before the first symptoms of Alzheimer’s show up. Studies done by examining the brains and retinas of people after death show a correlation between amyloid deposits in the retina and the severity of Alzheimer’s disease in the brain.
The exciting part is that this would be a low-cost, non-invasive test, meaning more people can get early detection and treatment for Alzheimer’s. And it will assist in the development and tracking of new treatments. Campbell’s team has spun off a new startup company called LumeNeuro, to assist in the commercialization of an instrument under development to measure amyloid in the living eye.
Early detection could happen in optometrists’ offices
“We would hope that the instrument could be in optometrists’ and ophthalmologists’ offices, in hospitals and community memory clinics,” Campbell says. Dependent on the test results, patients would be referred to a neurologist.
Bill McIlroy, a professor in the Faculty of Applied Health Sciences, is also part of the Ontario Neurodegenerative Disease Research Initiative (ONDRI.) He’s studying how the brain and other parts of the central nervous system control movements of the body so that his research team can help people recover after a stroke.
With all the neurodegenerative disease research that is happening, Hudson has reason to feel optimistic about future treatments for Parkinson’s. For now, he just stays in the fight. He is aggressively confronting every aspect of his Parkinson’s, emotionally as well as physically. He stays positive. “There are worse diseases than Parkinson’s,” he says.
Professor Chris Hudson works out in the boxing fitness class at the YMCA
After he was diagnosed, he went through an emotional rough patch. “It had a massive impact on my life and it was not easy to deal with,” he says. This year, a new chapter opened in his personal life when he and his fiancée Kristina Domysheva married in Cyprus.
On the health side, he tries to be as consistent as possible with his medication. He’s careful about what he eats, especially avoiding red meat. In addition to boxing, he maintains an exercise routine that alternates between light weight training one day and cardio workouts on his home treadmill the next.
Hudson finishes the intense workout that includes aerobic exercises, shadowboxing, punching the speed bags and heavy bags, and hitting against the trainer’s focus mitt as he practises his boxing moves.
The exercise helps, he says. But so does his work and his social engagement with others. “I confront the Parkinson’s at every opportunity,” Hudson says.
“I imagine it as a game that never ends. For every punch it gives me, I give it 10 back.”
Chris Hudson, professor in the School of Optometry and Vision Science
Photos: Memory Tree
Illustration: Kellen Hatanaka
