High-tech implant helps paralyzed man walk more naturally
By Dennis Thompson
health day reporter
WEDNESDAY, May 24, 2023 (HealthDay News) — A Dutch man with paralyzed legs can now stand and walk, thanks to a wireless brain-spine interface that responds to his thoughts by moving his legs.
Gert-Jan Oskam, 40, suffered a spinal cord injury 11 years ago following a cycling accident in China that left him unable to walk.
Oskam now has a brain implant that picks up motion signals that, in a healthy person, would travel along the spinal cord and move the legs. Instead, this implant transmits those signals wirelessly to a second implant in his lower spine, which then stimulates the leg muscles into action, the researchers report.
This experimental high-tech “digital bridge” between the brain and the spine allowed Oskam to pick up a brush the other day and perform a simple low-tech chore around his house in the Netherlands.
“Something needed to be painted and there was no one to help me, so I had to walk around and paint,” Oskam said during a press briefing on Tuesday. “I did it myself, while I was up.”
Researchers have been trying for years to restore the ability to walk using nerve stimulators implanted in patients’ spinal cords.
However, these test subjects often walked robotically and were unable to adapt their leg movements to different terrains.
Oskam benefited from the next step in this research, a way to allow the brain to control spinal stimulation and create a more natural stride for patients.
“What we’ve been able to do here is restore communication between the brain and the region of the spinal cord that controls leg movement with a digital bridge that picks up Gert-Jan’s thoughts and translates those thoughts into stimulation of the spinal cord to restore voluntary movement of the legs,” said lead researcher Grégoire Courtine, a neuroscientist and professor at the École Polytechnique Fédérale de Lausanne, France.
Oskam says he can now walk 100 to 200 meters (up to about 660 feet) at a time and can stand without using his hands for two or three minutes.
The device also improved Oskam’s neurological recovery. He was able to walk on crutches even with the implant off.
More natural movement
Oskam already had a spinal stimulator implanted in his back, due to his participation in previous studies. It allowed him to move, but his movements were robotic and stiff.
“It wasn’t quite natural. The stimulation used to control me, and now I control the stimulation by my thoughts,” Oskam explained.
The researchers developed a passive implant located above the motor center of his brain that could pick up signals that would normally control movement.
Using a special helmet and walker, Oskam can take more natural steps as the brain implant picks up motion signals and then transmits them to the spinal stimulator.
“We were able to calibrate the first models within minutes, which allowed Gert-Jan to control the flexion of his hips. And after several minutes of training, he was able to walk naturally using the system,” said lead researcher Henri Lorach, a professor at École Polytechnique Fédérale de Lausanne.
“We were able to not only decode single movements, but also hip, knee and ankle movements,” Lorach added. “And with this strategy, we really provided voluntary control of spinal cord stimulation to the participant.”
Because Oskam can control so many parameters of leg movement — and receive feedback as he moves — he can walk on all kinds of different terrain, Courtine said. He can climb stairs, progress on ramps, stop and start again as he pleases.
The brain-spine interface also seemed to speed Oskam’s recovery. After 40 neurorehabilitation sessions, his ability to walk has improved significantly – he can move around his house independently, get in and out of a car, or have a drink with friends standing in a bar, the researchers reported. .
“Without stimulation now, I can also walk,” Oskam said. “I think that says a lot. I regained enough strength and movement to take steps.
Spinal stimulation has already been shown to trigger the growth of new nerve connections, Courtine noted.
“When the brain controls the stimulation, there is even more recovery because it is a convergence of the digital connection with the natural connection on the same type of neurons,” explains Courtine.
More research needed
The new study was published May 24 in the journal Nature.
The research team hopes to recruit a second patient with lower body paralysis to receive the brain implant, to see if the same system will work in others.
Marco Baptista, scientific director of the Reeve Foundation, agreed that the technology needed to be tested on more people.
“It needs to be expanded and studied in other people who have different types of injuries,” Baptista said.
At the same time, Baptista noted that the effort represents the “next generation” of research into restoring movement through spinal stimulation.
“They’re moving more and more towards a more natural process, where you have the mind and the will controlling the stimulation,” Baptista said.
Researchers are also launching another clinical trial that will help people with upper body paralysis.
“We are indeed investigating how we can use the same principle to restore upper extremity function by targeting the cervical spinal cord with similar technology,” Lorach said. “We can decode what the intention is to move the arm and hand and stimulate the motor impulse that will trigger that activity.”
They also want to further miniaturize the technology, so it will be easier for people to participate in daily activities without having to wear caps or lug gear, Courtine said.
“We could even apply it to other pathologies such as stroke, in which we can also record cortical activity and link it to stimulation of the spinal cord to move a limb”, explains co-researcher Dr Jocelyne Bloch, neurosurgeon at the University Hospital of Lausanne. “You would think there are many different applications for this pioneering new therapy.”
More information
The University of California San Diego knows more about spinal cord injury and paralysis.
SOURCES: Gert-Jan Oskam, 40, Netherlands; Gregoire Courtine, PhD, neuroscientist and professor, Ecole Polytechnique Fédérale de Lausanne, France; Henri Lorach, PhD, professor, Ecole Polytechnique Fédérale de Lausanne, France; Marco Baptista, PhD, Scientific Director, Reeve Foundation, Short Hills, NJ; Jocelyne Bloch, MD, neurosurgeon, University Hospitals of Lausanne, France; NatureMay 24, 2023
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