The hi-tech implant helps the paralyzed person to walk more naturally
By Dennis Thompson
Health Day reporter
WEDNESDAY, May 24, 2023 (HealthDay News) — A Dutch man with a paralyzed leg can now stand and walk thanks to a wireless brain-spinal interface that responds to his thoughts by moving his legs.
Gert-Jan Oskam (40) suffered a spinal cord injury in a cycling accident in China 11 years ago, which left him unable to walk.
Oskam now has a brain implant that picks up movement signals that would travel through the spinal cord in a healthy person and cause the legs to move. Instead, this implant wirelessly transmits these signals to a second implant located in the lower spinal column, which then stimulates the muscles in the leg, the researchers reported.
This experimental, high-tech “digital bridge” between the brain and the spine allowed Oskam to pick up a paintbrush the other day and do a simple low-tech chore in his home in the Netherlands.
“I had to paint something and there was no one to help me, so I had to walk around and paint,” Oskam said at a news conference Tuesday. “I did it myself while I was standing.”
For years, researchers have been trying to restore the ability to walk with the help of nerve stimulators implanted in the spinal cord of patients.
However, these experimental subjects often walked robotically and could not adapt their leg movements to different terrains.
Oskam benefited from the next step in research that allows the brain to control spinal cord stimulation and create a more natural gait for patients.
“What we’ve been able to do here is restore communication between the brain and the part of the spinal cord that controls leg movement with a digital bridge that captures Gert-Jan’s thoughts and converts those thoughts into stimulation of the spinal cord. to restore voluntary leg movement,” said the lead researcher Gregoire Courtinneuroscientist and professor at the École Polytechnique Fédérale de Lausanne in France.
Oskam says he can now walk 100 to 200 meters (about 660 feet) at a time and stand for two to three minutes without using his hands.
The device also improved Oskam’s neurological recovery. He was able to walk with crutches even when the implant was off.
A more natural movement
Oskam has already had a spinal stimulator implanted in his back due to his participation in previous studies. This allowed him to move, but his movements were robotic and stiff.
“It wasn’t quite natural. The stimulation used to control me, now I control the stimulation through my thoughts,” explained Oskam.
Researchers have developed a passive implant that sits above the brain’s motor center and can pick up signals that control normal movement.
By using a special headset and walker, Oskam can take more natural steps, as the brain implant picks up movement signals and transmits them to the spinal stimulator.
“Within a few minutes, we were able to calibrate the first models, which allowed Gert-Jan to control the bending of his hips. And after a few minutes of training, he was able to walk naturally with the help of the system,” said researcher Henri Lorach, professor at the École Polytechnique Fédérale de Lausanne.
“We were able to decode not only simple movements, but also the movements of the hip, knee and ankle joints,” added Lorach. “And with this strategy, we really gave the participant voluntary control over the spinal cord stimulation.”
Because Oskam can control many parameters of leg movement – and receive feedback as it moves – it can walk on all kinds of terrain, Courtine said. You can go up stairs, go over ramps, and stop and go as you please.
The brain-spinal interface seems to speed up Oskam’s recovery. After 40 neurorehabilitation sessions, his ability to walk improved significantly – he can move around his house independently, get in and out of a car, or have a drink with his friends at a bar, the researchers reported.
“Now I can walk without stimulation,” Oskam said. “I think that says a lot. I have regained enough strength and movement to take steps.”
It has previously been shown that stimulation of the spinal cord can trigger the growth of new nerve connections, Courtine noted.
“When the brain controls the stimulation, the recovery is even greater because it’s a convergence of the digital connection and the natural connection of neurons of the same type,” explained Courtine.
More research is 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 works in others.
Marco Baptista, scientific director of the Reeve Foundation, agreed that the technology needs to be tested on more people.
“It needs to be expanded and tested in other individuals with different types of injuries,” Baptista said.
However, Baptista noted that this effort represents the “next generation” in research into restoring movement through spinal cord stimulation.
“They’re moving more and more toward making the whole process more natural, where thought and will control the stimulation,” Baptista said.
Researchers are also launching another clinical trial to help people with upper body paralysis.
“We’re actually looking at how we can use the same principle to restore upper limb function by targeting the cervical spinal cord with a similar technology,” Lorach said. “We can decode what the intention is to move the arm and hand and stimulate the motor impulse that triggers that activity.”
They want to further miniaturize the technology, making it easier for people to participate in everyday activities without having to wear a hat or lug the equipment around, Courtine said.
“We can also apply it to other pathologies, such as stroke, in which you can record cortical activity and connect it to spinal cord stimulation to move a limb,” said Dr. Jocelyne Bloch, a neurosurgeon at Lausanne University Hospital. “You’d think there would be many different applications for this novel, ground-breaking therapy.”
The University of California, San Diego is more concerned with spinal cord injuries and paralysis.
SOURCES: Gert-Jan Oskam, 40, Netherlands; Gregoire Courtine, PhD, neuroscientist and professor, École Polytechnique Fédérale de Lausanne, France; Henri Lorach, PhD, Professor, École Polytechnique Fédérale de Lausanne, France; Marco Baptista, PhD, Chief Scientific Officer, Reeve Foundation, Short Hills, NJ; Jocelyne Bloch, MD, neurosurgeon, Lausanne University Hospital, France; NatureMay 24, 2023