the neuroscientist Gregoire Courtinefrom the Federal Polytechnic School of Lausanne (EPFL), together with the neurosurgeon Jocelyne Bloch, from the EPFL University Hospital Center in Vaud (both in Switzerland), have been researching for years how people with spinal cord injuries can walk again. In 2018, they managed to get three men paralyzed for several years to achieve this goal, after inserting implants into their spinal cord.
Now, a team led by both researchers has developed a wireless technology that has allowed Gert-Jan, a 40-year-old Dutchman, to walk again who, a decade ago, suffered paralysis of the legs due to damage to the spinal cord after a motorcycle accident.
The ‘digital bridge’ between the brain and spinal cord allowed the patient to regain natural control of leg movement, standing up, walking and even climbing stairs
“We created a ‘digital bridge’ between the brain and the spinal cord, through a brain-computer interface (BCI), which transforms thought into action with artificial intelligence algorithms”, says Courtine, leader of the study published in Nature.
The patient takes control
The authors explain that this technology allowed the patient to regain natural control of the movement of his paralyzed legs. Furthermore, after several rehabilitation sessions with the BCI, the team quantified remarkable improvements in their sensory perceptions and motor skills that were maintained even when the device was turned off.
In this sense, Andrea Galvez Solano, EPFL researcher and first signatory of the work, comments to SINC that “the novelty of the BCI is that the patient can control the stimulation —and therefore the movements— directly through his thoughts” .
According to Galvez, “this means that he is able to take longer or shorter steps, walk on different surfaces and even climb stairs, adapting to everyday environments. The simultaneous activation of neurons above and below the lesion, which the interface allows, together with targeted rehabilitation sessions, is likely to promote neurological recovery and improve the patient’s clinical condition, he stresses.
To establish the digital bridge, two types of electronic implants were needed. Bloch explains: “We have implanted electrodes, developed by the research center CEA, in the region of the brain that controls leg movement. These devices allow us to decode the electrical signals generated by the brain when we think about walking. We also “placed a neurostimulator connected to a set of electrodes over the region of the spinal cord responsible for the lower extremities.”
The man received two implants in his brain, in the area that controls leg movement, and another in his spinal cord.
For his part, Guillaume Charvet, head of the BCI program at CEA, comments that “thanks to the use of adaptive artificial intelligence algorithms, the patient’s movement intentions are decoded in real time from brain records”.
“These intentions are then converted into electrical stimulation sequences of the spinal cord, which in turn activate the leg muscles to achieve the desired movement. This digital bridge works without wires, which allows the patient to move autonomously”, underlines the specialist.
Other possible applications
Gert-Jan says that, ten years later, she has recovered the pleasant feeling of being able to share a beer standing up in a bar with friends: “This simple pleasure represents a significant change in my life”, she says with satisfaction.
So far, the BCI system has only been tested with it. However, according to Galvez, “In the future, a similar strategy could be used to restore arm and hand function. And it can also apply to other neurological problems, such as paralysis due to a stroke.”
The company AVANT Medicaltogether with CEA and EPFL, it received support from the European Commission through its European Innovation Council to develop a commercial version of the digital bridge, with the aim of making the technology available worldwide.
Reference:
G. Courtine et al. “Walking naturally after spinal cord injury using a brain-spine interface”. Nature (May 2023)