Brain-spinal cord digital bridge, paralyzed for 11 years walks again

Brain-spinal cord digital bridge, paralyzed for 11 years walks again

Eleven years without moving legs and arms. The state in which Gert-Jan, 40, had to live after a terrible traffic accident, it seemed irreversible. Nothing to do, most thought, a marked life. That wasn't the case, because Gert-Jan, who had been paralyzed for all that time, was able to walk again thanks to a digital bridge that allows his brain to communicate directly with the areas of the spinal cord that control his movements. In essence, it is enough for him to think to move. This was possible thanks to the research group of the Polytechnic University of Lausanne led by Gregoire Courtinethe same one who in February 2022 had experimented with a system of electrodes that can be controlled with a tablet, which sent electrical stimuli to the muscles in a programmed way.

A digital bridge

For now, Gert-Jan is the only person on whom the new technique has been tested, a study published in the scientific journal natures. Which, given the results, is promising and "could be replicated - the researchers explain - in patients with motor deficits due to neurological disorders.
A premise: the goal is to allow paralyzed people to move again in the most natural way possible, for example by adapting their pace even on uneven terrain, without losing their balance.
It is the authors of the research who clarify what we are talking about: "It is a completely different approach from what we have adopted in the past - said Courtine in a press conference organized by natures -. It's a digital bridge, the one we've established between the brain and the spinal cord. It is not a simple stimulation, but an interface that makes possible a direct conversation between the brain and the spinal cord". That is to say that "there is a synchrony between the intention to walk and the action of walking ". In practice, it is the brain that calibrates the commands, adapting them in real time to the situation that the patient is facing.

The new technique

But what does the new technique consist of? In the event of a spinal cord injury, the researchers explain, there can be an interruption in the communication routes between the brain and the region of the spinal cord that controls walking. Previous approaches to restoring movement to people with paralysis relied on electrical stimulation of regions of the spinal cord to enable standing and walking. However, this method requires the use of motion sensors and has often been limited and limiting in adapting motion to different situations and environments.

64 electrodes in action

In this work, the researchers re-established the connection between the spinal cord and the brain, improving the timing and amplitude of muscle activity potential. The brain-spine interface (BSI) was able to calibrate itself within minutes and remained stable for over a year, even without supervision from the scientists. We are talking about 64 electrodes that record the signals of the sensorimotor cortex using frequencies that artificial intelligence has allowed us to identify. Then the signals are translated into electrical signals and transmitted to the spinal cord, where they are received by 16 electrodes and decoded in real time, without the need for a computer for this function. All of this requires a wearable control system, contained in a backpack.

Walk naturally

After the treatments, the authors report, the patient, Gert-Jan, was able to move his arms and legs normally, stand and walk naturally. The device, the scientists add, also improved neurological recovery and allowed the patient to move on crutches even when the implant was turned off. These findings, the experts comment, "provide a new approach to restore natural motor control following paralysis."

The concept of a digital bridge between the brain and spinal cord, they point out, "could help improve the treatment of motor deficits due to neurological disorders." And Courtine concludes: "Our next goal is to have very small systems and we expect that the technique will have incredible developments thanks to miniaturization". Meanwhile, the researchers are working to continue the experimentation: the next stage involves three paralyzed people.

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