Three people who were once paralysed by complete spinal-cord injuries have been able to walk, swim and even work the pedals of a bike, thanks to a new implant that stimulates the neurons in their spinal cords. In new research published by Nature, a team at the Swiss Federal Institute of Technology in Lausanne (EPFL) have described the implant, which mimics the signals the lower body usually receives from the brain, tackling a form of paralysis that is usually irreversible. The implications of this research are significant – if it can be refined and employed more widely, it’s possible it may be one of the first steps towards solving spinal cord injury.
Spinal-cord paralysis occurs after the spinal cord is severed, disrupting the flow of electrical signals from the brain that tell the body below the injury how to balance and move. This leads to a form of paralysis that is usually irreversible. The chain of motor neurons below the break often remains intact, and so if it is theoretically possible to use electrical impulses to boost or mimic these signals from the brain, they could make the lower half of the body move. This has been the focus of research in this field, with the EPFL team building on their own work from 2018.
If it can be refined and employed more widely, it’s possible it may be one of the first steps towards solving spinal cord injury
Three patients, all of whom were unable to move their lower bodies after accidents, underwent surgery to have a six-centimetre implant fitted. MRI technology and computed tomography were used to map the neurons, and create a predictive model of the average spinal cord, while the electrical current was fine-tuned for each person. The electrodes were longer and larger than in previous studies, meaning they could access more muscles than before.
Professor Jocelyne Boch, a neurosurgeon at Lausanne university hospital, explained that all three patients were able to stand within hours of the operation (using support bars), and their performance improved with three to four months of practice and training: “It was not perfect at the beginning, but they could train very early to have a more fluid gait”. They follow a training programme that lets them rebuild lost muscle and move around more independently – to perform a certain action, the person selects an option from a tablet. It connects to a device in their abdomen which sends signals to the implanted electrode, stimulating different sets of muscles for the right time and duration to complete whichever task they choose. It has now been reported that two of the patients can activate their muscles slightly without electrical pulses, but minimally.
A cure would require regeneration of the spinal cord, possibly using stem cell therapies, which are at an early stage of research
Professor Grégoire Courtine, who led the EPFL team, said this was a small step forward, and that there is a long way to go before the technology can routinely help paralysed people. He said: “This is not a cure for spinal cord injury. But it is a critical step to improve people’s quality of life. We are going to empower people. We are going to give them the ability to stand, to take some steps. It is not enough, but it is a significant improvement.” Such a cure would require regeneration of the spinal cord, possibly using stem cell therapies, which are at an early stage of research. However, Prof Courtine believes the implant could be used in conjunction with these treatments when they are ready.
Even still, the advent of this technology is reshaping the lives of the patients who are benefitting from it. One, Michel Roccati, who was paralysed after a motorbike accident five years ago, described it as “a gift to me” – the quality-of-life improvements are clearly immeasurable. It may be a small step towards curing paralysis, but that shouldn’t lessen the impact now. There are already plans for large-scale trials and refining the computer-pulse programme, so this technology could be with us a lot sooner than expected.