Susan Fullerton
Susan Fullerton shares her impressions and personal outcomes as a participant of a Phase 1 clinical trial for an experimental new treatment for Parkinson's disease.

The Heart of Research: One Volunteer’s Experience as Part of a Clinical Trial


At the heart of the clinical studies carried out by researchers seeking better treatments or a cure for Parkinson’s, are the volunteers, ordinary people just like you, helping to advance the science and potentially improving or even saving lives in the decades to come through their participation.

Susan Fullerton is one of those brave volunteers. She chose to participate in an experimental Phase 1 clinical trial carried out by a team of researchers from Sunnybrook Health Sciences Centre and University Health Network. The team, which received grants funded by the Parkinson Canada Research Program, used focused ultrasound technology to deliver a therapeutic directly to affected brain regions in people with Parkinson’s.

Susan has graciously shared her impressions and personal outcomes of the clinical trial experience with us.

As she describes it, Susan’s situation was “a little bit unique” because she was a dual diagnosis patient, having been diagnosed with Gaucher disease in and Parkinson’s in . Individuals diagnosed with Gaucher’s have a higher likelihood of getting Parkinson’s.

When her neurologist, Dr. Lorraine Kalia, one of the study’s lead investigators and a member of the Parkinson Canada Scientific Advisory Council, asked if she would participate, Susan didn’t hesitate. Despite the potential, albeit low, of risks of stroke and even death, she agreed to take part.

“I recognize that they can get data from me that they can’t get from other people. And I’m in a situation where I don’t have the significant barriers to participation that others might have. I don’t have children, and I have a good job. On the personal side, I’ve always had a strong desire to make a difference in the world somehow, to help others. The question that presents itself in a situation like this is ‘If not me, then who?’ So, I really didn’t give it much pause before I agreed.”

Focused ultrasound harnesses the power of ultrasound waves to reach deep brain regions without the need for scalpels or cutting. In this study, researchers are using low-intensity MRI-guided focused ultrasound to open the blood-brain barrier, which protects the brain from toxins but can also block potentially helpful medications. Susan’s procedures took place over several weeks and involved pre-and post-testing.

“You never know until well into the process if you are going to be eligible. So, I was committed, but at the same time, I had to try not to get my hopes up too much. I underwent CAT scans, EKGs and a spinal tap along with many of the typical Parkinson’s tests such as finger and foot tapping. Then COVID came along, and everything was delayed until January.”

Finally, it was time for the procedure itself. Before it, doctors covered Susan’s head and videotaped all tests, so it would be impossible for any outside reviewers involved in the study to tell whether they were done pre- or post-treatment. According to Susan, doctors used the same type of headframe used to carry out deep brain stimulation (DBS).

“While they were shaving my head and fitting me with the head frame, they were injecting me with the therapeutic. And then I went into the MRI tube. And while you’re on the MRI table, they are injecting the bubbles into your bloodstream, and the ultrasound is directing these microscopic bubbles to the right place so they can bump up against and make microscopic tears in the blood-brain barrier, which closes again within a few hours.”

Promising treatments (such as enzyme replacement therapy) to reduce an abnormal accumulation of a protein in the brain, which leads to neurodegeneration, have been limited by their previous inability to cross the blood-brain barrier. Doctors performed the ultrasound procedure three times on Susan over six weeks. She suffered no treatment-related side effects other than a slight headache from the head frame. Then doctors did all the same tests again, videotaping them for comparison with the first videotaped tests.

Susan came into the trial with limited expectations. “Of course, they make no promises because it’s Phase 1, and they just want to see if they can do this safely.” However, to her surprise, she noticed some immediate changes. The first was the return of her sense of smell. “I walked into the room with the cat box, which my brother hadn’t changed for a day or so while I was in the hospital. And I could clearly smell it. In my excitement, I shared that on social media, and one of my friends then sent flowers because she said you should be celebrating the return of your sense of smell with something beautiful!”

Susan also noticed other physical changes, including an improved ability to tap her hands and an improved gait. “I felt like I was back to the earlier days of my diagnosis.”

Unfortunately, the improvements were relatively short-lived. “I think that was the hardest adjustment. It was that I saw an improvement, and since then, I’ve just been decompensating. But I had several months of feeling better, and it definitely made a difference in my tremors, my walk, and other symptoms.”

Susan would encourage those who can participate in medical research. “The more information the researchers have, the more data in the way of tissue or ambient blood samples or genetic material; that’s the way we advance the cause of finding a cure.”

There are a range of ways you can contribute to furthering Parkinson’s research in Canada. Some are as complex as this trial, but others are much more accessible, like answering a survey, sharing blood samples, or simply donating to support research. Learn more on our new research portal at

Susan’s participation in this Phase 1 clinical trial was an exciting first step in the use of focused ultrasound. Already, her participation has made a substantial contribution to finding new and better personalized treatments for other people living with Parkinson’s.

Given the admitted challenges of participating, would she go through it again?

“I’d do it again in a heartbeat.”

For more on this clinical study, please read our previous ePP article.

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