Gert-Jan Oskam, who suffered a spinal cord injury in a bicycle accident eleven years ago, has become the first paraplegic to regain the ability to stand up and walk by controlling his legs naturally. His recovery has been possible by reconnecting the brain and spinal cord with a wireless technology developed by the team of Grégoire Courtine and Jocelyne Bloch in Lausanne (Switzerland), world pioneers in this field of research.
"Our goal is to make this technology available around the world for all patients who need it," declared Grégoire Courtine, from the Ecole Polytechnique Federal de Lausanne (EPFL) and the hospital, at a press conference on Tuesday. University of Lausanne. The researchers have founded the company Onward Medical with funding from the European Commission to develop a commercial version of the technology, which is now experimental.
Courtine cautioned that Gert-Jan Oskam is the only person to have received the treatment and that studies with more participants will be needed in the coming years before the technology can be applied on a large scale.
"The sensation is very similar to the normal sensation of walking. I feel like I'm applying force to the ground, which allows me to take a good step. I'm practicing the quality of my steps," Oskam, who has been collaborating as a volunteer in Courtine and Bloch's research since 2017, declared at the press conference.
He regained the ability to start walking in an earlier trial, in which electrodes were implanted in his spinal cord to control his leg muscles. Although it was a significant improvement, “the stimulation was not natural,” explained Oskam. "Before the stimulation controlled me; now I control the stimulation".
His ability to walk is far from what it was before he suffered the spinal cord injury. He walks a hundred or two hundred meters a day, stands without supporting himself with his hands for two or three minutes, and can climb stairs. But he perceives movement as fluid and natural. "Before the stimulation was activated by a computer; every step was a bit stressful because I had to pace it with the rhythm [of the neurostimulator]; now I can do what I want", he explained.
The treatment that Oskam has received consists of two electrode implants, the researchers report in the journal Nature, where they presented the advance yesterday. One of the implants is placed on the head to record the brain signals that encode the will to walk. The other is placed in the spinal cord, below the point of spinal cord injury, to transmit signals to the legs.
"We capture the brain's natural control signal and reconnect two regions of the nervous system that had been disconnected", explained Grégoire Courtine, who has devoted twenty years to this line of research.
The signals recorded in the brain are processed with algorithms based on artificial intelligence to interpret in real time the intention to walk. The signal is transmitted to a neurostimulator that activates electrodes in the spinal cord. These electrodes, in turn, activate neurons that reach the appropriate muscle groups to make the desired movement. This establishes what Courtine calls "a digital bridge without cables" between the brain and the spinal cord.
"When I met Grégoire eleven years ago and he explained this idea to me, it seemed like science fiction," admitted neurosurgeon Jocelyne Bloch, who is now co-director of the project, at the press conference.
Once the electrodes are implanted, rehabilitation treatment under medical supervision is necessary so that the patient learns to master the implants and regain voluntary control of walking. In the case of Oskam, his evolution was so good that the medical team proposed that he use this experimental technology in his daily life, outside the hospital.
To the surprise of the medical team following him, his abilities improved not only when he had the electrodes on, but also when he had them off. He can now lift one leg or walk with crutches without the need for neurostimulation.
According to the researchers, the neurostimulation led to a reorganization of their neural circuits. Therefore, the neurological improvement that can be expected in other patients in the future will depend on the severity of their spinal cord injury. In Oskam's case, the injury was severe but not complete.
"We have understood how to dialogue with the spinal cord," declared Courtine. "Paralysis is the tip of the iceberg of spinal cord function. Now we can start working on controlling the bladder or blood pressure."
The Lausanne team also plans to test the technique on people with quadriplegia to regain control of their arms and hands, as well as on people who have been disabled after suffering a stroke.
"Although these developments will require time and resources, we do not anticipate that there will be technical obstacles", the researchers conclude in Nature. "The concept of a digital bridge between the brain and the spinal cord heralds a new era in the treatment of motor deficits due to neurological disorders".