A quadriplegic manages to walk and control his gait with his thoughts thanks to a 'digital bridge' between the brain and the spinal cord
In 2011, the Dutchman Gert-Jan Oskam had a serious cycling accident in China. His spinal cord was badly damaged, with an incomplete injury that after much rehabilitation barely allowed him to move his arms.
From the beginning, his goal was to try to recover as much mobility as possible, so when he was told about a group of leading researchers from Lausanne (Switzerland) trying to find ways to help patients with spinal cord injuries, he did not hesitate to call his door.
He was one of five participants who took part in the STIMO trial, a neurorehabilitation program that, through epidural electrical stimulation of the spinal cord, demonstrated that it was possible to recover some motor capacity.. Thanks to the program Oskam, who is now 40 years old, was able to walk again with the help of a walker.
After three years, the Dutchman had reached the limit of possible recovery, so he had no doubts when the multidisciplinary team led by Grégoire Courtine, from the Federal Polytechnic School of Lausanne (EPFL), and the neurosurgeon Jocelyne Bloch, from the University Hospital of Lausanne, he was asked to participate in a new trial, called STIMO-BSI, which wanted to go a step further in the approach.
The results of this strategy, which makes it possible to establish a direct link between the brain and the spinal cord and provides voluntary and more natural control of motor capacity, have meant a qualitative leap in Oskam's quality of life, as he pointed out in a conference press. Can perform tasks such as standing up, walking, climbing stairs, and adapting to different terrains. The implantation of the device has also allowed him to improve neural recovery, so that he is now able to walk with crutches even when the implants are turned off.. “These improvements are very useful in my day to day. They help me a lot,” he stressed.. Details of the case are published this week in the journal Nature.
What is the digital bridge that allows motor function to be recovered?
What the researchers have developed is a kind of 'digital bridge' that, to a certain extent, makes it possible to restore the line of communication that exists between the brain and the area of the spinal cord that allows walking and that, in the case of Oskam, was damaged by the accident.
Through implants in the brain, the system is capable of capturing cortical signals, the 'orders' that the brain sends when we want to stand up or take a step. These signals, duly decoded using artificial intelligence methods, are sent to a stimulation system implanted in the epidural region, where the gait pattern generating center is located, allowing the muscles involved to start up according to the instructions received.
“It allows me much more control. Now I control the stimulation with my thoughts,” Oskam told reporters, a point Courtine also underlined.
Oskam walking in the park. CHUV
Although it has given very good results, by itself the epidural electrical stimulation of the spinal cord that the team had previously used has some drawbacks, such as the fact that the patient must use a knob or button to initiate the stimulation or that it is complicated adapt movements to changes in the terrain or to the needs of each task.
It allows me much more control.. Now I control the stimulation with my thoughts
This new direct connection between the brain and the spinal cord, on the other hand, allows for more natural movements, adapted to each moment, since they occur in real time.. In addition, it also allows a greater range of movement, for example, in hip flexion or knee extension, said the researchers, who want to extend the trial to more patients and explore the usefulness of the device in other cases, such as paralysis of the upper extremities.
“It is very interesting work that follows the line that this team began more than 10 years ago,” says Joan Vidal, rehabilitation physician, teaching director of the Institut Guttmann in Barcelona and principal investigator of the 'Neuroreparation and advanced therapies' line of research at the said center.
Both the use of cortical receptors and epidural stimulation are techniques that have been used previously. The novelty lies in the fact that this system combines them, providing voluntary control, “which is very interesting”, emphasizes the specialist.
For Vidal, one aspect of the work that should be highlighted is that it shows that after the implantation of the device and through rehabilitation, there is some functional recovery, the patient is able to walk again with crutches even when the implants are not connected.
“The central nervous system has a plastic capacity, to generate new connections. And this once again shows that neuromodulation combined with neurorehabilitation can favor these new neural networks that allow a certain recovery,” he points out.
After turning off the systems it seems that the patient is a little better, there is some functional recovery
Antonio Oliviero, head of the Laboratory for Functional Exploration and Neuromodulation of the Nervous System at the National Hospital for Paraplegics in Toledo, pronounced himself along the same lines: “One of the facts that most strikes me is that not only does this possibility of walking exist when the stimulator and the interface are working but after turning off these systems it seems that the system is a little better, there is a certain functional recovery and this allows us to think of these devices not only as substitutes for anatomical and functional injury but also as important tools rehabilitation,” he says.
In the future, the use of this type of device could also be considered in other types of motor disorders, such as those that occur after a stroke, both specialists agree.
“In the last 10 years, much progress has been made.. We are closer to understanding which are the lines of research where it is necessary to deepen, where it is necessary to invest, but there is still a long way to go”, remarks Vidal, who calls for caution so as not to generate false expectations in patients. “This research has been carried out on a single patient,” he stresses.. The progress made is still limited and this type of device still needs more research before it can be approved by regulatory agencies, he recalls.