Experimental spinal cord implant helps Parkinson’s patient walk in new study

By Jacqueline Howard, CNN

(CNN) — Marc Gauthier can now step into an elevator without his body stiffening and freezing in place. He can take a 3-mile lakeside stroll without stopping. He can stand up out of a chair with ease. For Gauthier, 63, who has been living with Parkinson’s disease for almost three decades, these everyday activities were a challenge — until now.

“Walking in a store would be really difficult, impossible before, because of the freezing of gait that would often happen in those environments. And now, it just doesn’t happen anymore. I don’t have freezing anymore,” Gauthier, who lives near Bordeaux, France, said in a news briefing, speaking in French that was translated to English.

In a new study, Gauthier was surgically implanted with an experimental spinal cord neuroprosthesis to correct walking disorders in people with Parkinson’s disease. Step by step, he said, it has helped him get his stride back.

The study, published Monday in the journal Nature Medicine, details how the neuroprosthesis works by targeting specific areas of the spinal cord with electrical stimulation that are associated with walking.

“Addressing deficits of gait and balance in Parkinson’s disease is extremely challenging. These deficits can be very heterogenous. They can be variable across patients. They can affect walking but also symmetry, balance, posture,” Dr. Eduardo Moraud, an author of the study and researcher at Lausanne University Hospital in Switzerland said during the news briefing.

“The neuroprosthetic approach that we have developed here allows for the first time to target and address these problems individually in a highly specific manner for each patient,” Moraud said. “It operates in real time, and importantly, it is complementary to other existing therapies.”

Parkinson’s disease, a degenerative brain disorder, causes parts of the brain to deteriorate. Symptoms related to walking occur when the nerve cells in the brain’s basal ganglia area, which controls movement, become impaired or die. These nerve cells normally produce dopamine but, when they die or become impaired, the lack of dopamine often impacts a person’s ability to move, walk or balance. About 90% of people with the disease experience locomotor deficits. While there is currently no cure for Parkinson’s disease, some therapies — such as deep brain stimulation or medications to increase dopamine levels — may relieve symptoms.

Gauthier, a father of two, was diagnosed with Parkinson’s when he was 36 years old and was previously treated with dopamine replacement therapy and then deep brain stimulation in 2004 to help with tremors and stiffness. But more recently, as the disease progressed, he developed severe walking disorders that did not respond to either therapy. His body would often stiffen, he said, and he had falls about four times a day on average, forcing him to stop his work as an architect.

Then, Gauthier was invited to participate in the new study to test the experimental spinal cord neuroprosthesis. At first he declined because of the time commitment, he said, but then changed his mind, took a “chance” and said yes.

Stimulating the spinal cord

To develop the implant, researchers from France, Switzerland and other institutions around the world visualized and mapped which hotspots in the lower spinal cord the neuroprosthesis must target with electrical stimulation to alleviate gait impairments and balance problems in a patient with Parkinson’s disease.

“The stimulation here is focused on the spinal cord,” Moraud said. “We target the region of the spinal cord that will control all the leg movements.”

The researchers identified six hotspots to facilitate walking. Next, they implanted an array of electrodes against the lower region of Gauthier’s spinal cord to target those zones. The electrodes were linked to a neural stimulator placed under the skin in the region of the abdomen. That stimulator was programmed to apply electrical stimulation to the spinal cord.

“The connection between the electrode and the stimulator is under the skin, everything is hidden, and you control the device with a remote control,” neurosurgeon Dr. Jocelyn Bloch, an author of the study and professor at Lausanne University Hospital, said during the briefing.

The surgery was performed at Lausanne University Hospital about two years ago. And after a few months of rehabilitation with the neuroprosthetic stimulation, Gauthier has regained the ability to walk independently using the implant.

He also has the option to wear sensors on his legs to receive more of a stimulation. Signals from the wearable sensors can help synchronize epidural electrical stimulation to movements and reinforce movements.

Overall, the neuroprosthesis, based on epidural electrical stimulation, helped to “promote longer steps, improve balance and reduce freezing of gait,” the researchers wrote in their study.

Gauthier now uses his neuroprosthetic for about eight hours a day, turning on the stimulator in the morning and then turning it off when he is sitting down for long periods of time or sleeping. Gauthier said during the news briefing that he feels a little tingling on the legs with the stimulation, but it doesn’t bother him, and he joked that his wife is “very happy” that he now can get outdoors on his own while she can enjoy some quiet time at home.

But this is not a cure. The researchers expect his Parkinson’s disease to still progress.

“With this spinal cord stimulation, we still have an effect, but we have to fight against worse and more severe symptoms,” Bloch said. “But we can still give him, with the therapy, a bit of quality of life.”

‘An exciting development’

This proof-of-concept study is “exciting” and “impressive,” Dr. Svjetlana Miocinovic, a neurologist specializing in Parkinson’s disease and associate professor at Emory University School of Medicine, said in an email.

“This is an exciting development as better treatments for gait and balance impairment in PD are desperately needed,” said Miocinovic, who was not involved in the new research.

“It will be important to demonstrate that gait benefit observed in this study is specifically due to spinal stimulation (so comparisons with sham stimulation are important), that it can be achieved in other patients with PD,” she added. “And that it can be deployed in clinical practice (technology needs to be streamlined sufficiently for clinicians to implement and for patients to use).”

This technology not only needs to be tested in more people with Parkinson’s disease, but also those who had not previously received deep brain stimulation as a therapy, David Dexter, director of research at Parkinson’s UK, said in a written statement distributed by the UK-based Science Media Centre.

“This has so far only been tried in one individual with Parkinson’s who already had Deep Brain Stimulation. We now need to see this be tested in many more people with the condition, including those without DBS, in clinical trials to further explore the potential benefits and side effects/risks of this experimental new therapy,” said Dexter, who was not involved in the new study.

“This is quite an invasive procedure but could be a game changing technology to help restore movement in people with advanced Parkinson’s where the drugs are no longer working well,” he said. “This research is still at a very early stage and requires much more development and testing before it can be made available to people with Parkinson’s, however this is a significant and exciting step forward and we hope to see this research progress quickly.”

A second patient already has started the process of this therapy, Moraud said in the news briefing, and the researchers plan to conduct clinical tests next year in six other patients with Parkinson’s disease. This work is being supported by a $1 million donation from the Michael J. Fox Foundation. And in partnership with the Netherlands-based medical technology company ONWARD Medical, Bloch and Grégoire Courtine, an author of the study and professor of neuroscience at the Lausanne University Hospital, are working on developing a commercial version of the neuroprosthesis.

“The idea is, really after this first phase, to launch a larger scale clinical trial to really validate the therapy,” Courtine said during the news briefing, adding that this ongoing research will take some time, “at least five years of development and tests.”

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