Gert-Jan Oskam was living in China in 2011 when he had a motorcycle accident that left him paralyzed from the hips down. Now scientists have given him back control of his lower body with a combination of devices.
“For 12 years I’ve been trying to get back on my feet,” said Mr. Oskam in a press briefing Tuesday. “Now I’ve learned how to walk normally, naturally.”
In a study published Wednesday in the journal Nature, researchers in Switzerland described implants that formed a “digital bridge” between Mr Oskam’s brain and his spinal cord, bypassing injured areas. The discovery allowed Mr Oskam, 40, to stand, walk and climb a steep incline with only the aid of a walker. More than a year after the implant was inserted, he has retained these abilities and has actually shown signs of neurological recovery, walking with crutches even with the implant disabled.
“We captured Gert-Jan’s thoughts and translated those thoughts into spinal cord stimulation to restore voluntary movement,” Grégoire Courtine, a spinal cord specialist at the Swiss Federal Institute of Technology, Lausanne, who helped lead the research, said. during the press conference.
Jocelyne Bloch, a neuroscientist at the University of Lausanne who placed the implant in Mr Oskam added: “It was quite science fiction to me at first, but today it became true.”
There have been a number of advances in the technological treatment of spinal cord injury in recent decades. In 2016, a group of scientists led by Dr. Courtine managed to restore the ability to walk in paralyzed monkeys, and another group helped a man regain control of his crippled hand. In 2018, another group of scientists, also led by Dr. Courtine, a way of stimulating the brain with electrical pulse generators, enabling partially paralyzed people to walk and cycle again. Last year, more advanced brain stimulation procedures enabled paralyzed subjects to swim, walk and cycle within one day of treatment.
Mr. Oskam had undergone stimulation procedures in previous years and was even able to walk somewhat again, but eventually his improvement leveled off. During the press conference, Mr. Oskam said that these stimulation technologies had made him feel like there was something strange about his motor skills, a strange distance between his body and mind.
The new interface changed this, he said, “The stimulation used to control me, and now I control the stimulation.”
In the new study, the brain-spine interface, as the researchers called it, took advantage of an artificial intelligence thought-decoder to read Mr. Oskam’s intentions — detectable as electrical signals in his brain — and link them to muscle movements. The etiology of natural movement, from thought to intention to action, was preserved. The only addition, as Dr. Courtine described it was the digital bridge over the injured parts of the spine.
Andrew Jackson, a neuroscientist at Newcastle University who was not involved in the research, said: “It raises interesting questions about autonomy and the source of commands. You keep blurring the philosophical line between what the brain is and what the technology is .”
Dr. Jackson added that scientists in the field have theorized about connecting the brain to spinal cord stimulators for decades, but that this was the first time they had achieved such success in a human patient. “It’s easy to say, it’s much harder to do,” he said.
To achieve this result, the researchers first implanted electrodes in Mr. Oskam’s skull and spine. The team then used a machine learning program to observe which parts of the brain lit up as he tried to move different parts of his body. This thought decoder was able to match the activity of certain electrodes with certain intentions: one configuration lit up when Mr. Oskam tried to move his ankles, another when he tried to move his hips.
Then the researchers used a different algorithm to connect the brain implant to the spinal cord implant, which was set up to send electrical signals to different parts of his body, causing movement. The algorithm was able to account for small variations in the direction and speed of each muscle contraction and relaxation. And because the signals between the brain and spine were sent every 300 milliseconds, Mr. Oskam was able to quickly adjust his strategy based on what worked and what didn’t. Within the first treatment session, he was able to twist his hip muscles.
Over the next few months, the researchers refined the brain-spine interface to better suit basic actions like walking and standing. Mr. Oskam regained a somewhat healthy-looking gait and was able to negotiate stairs and ramps with relative ease, even after months without treatment. In addition, after a year of treatment, he began to notice marked improvements in his movement without the aid of the brain-spine interface. The researchers documented these improvements in weight-bearing, balance, and gait tests.
Now Mr. Oskam can walk around his house with restrictions, get in and out of a car, and stand at a bar for a drink. For the first time, he said, he feels like he’s in control.
The researchers acknowledged limitations in their work. Subtle intentions in the brain are hard to discern, and while the current brain-spine interface is suitable for walking, the same probably can’t be said for restoring upper body movement. The treatment is also invasive, requiring multiple surgeries and hours of physical therapy. The current system does not resolve all spinal cord paralysis.
But the team was hopeful that further progress would make treatment more accessible and systematically more effective. “This is our real goal,” said Dr. Courtine, “to make this technology available around the world to all patients who need it.”
