Breakthrough nerve-stimulation device helps paralysed patients walk, swim

Three patients whose lower bodies were left completely paralysed after spinal cord injuries have been able to walk, cycle and swim using a nerve-stimulation device controlled by a touchscreen tablet.

According to reports released on Monday, the patients were able to take their first steps within an hour after neurosurgeons first implanted prototypes of a nerve-stimulation device remotely controlled by artificial-intelligence (AI) software.

The injuries were to a region called the thoracic spine, below the neck and above the lowest part of the back, and were sustained one to nine years before receiving the treatment.

Following the first implantation over the next six months, the patients regained the ability to engage in the more advanced activities - walking, cycling and swimming in community settings outside of the clinic - by controlling the nerve-stimulation devices themselves using a touchscreen tablet, the researchers said.

Grégoire Courtine and Jocelyne Bloch of the Swiss Federal Institute of Technology in Lausanne led the study published in the journal Nature Medicine. They helped establish a Netherlands-based technology company called Onward Medical that is working to commercialise the system.

The company expects to launch a trial in about a year involving 70 to 100 patients, primarily in the United States, Courtine said.

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Tailored to each patient’s anatomy

Normally to initiate movement the brain sends a message to the spinal cord, telling it to stimulate a pool of nerve cells that in turn activate the necessary muscles, Bloch said.

"It's something we don't even think about," Bloch said. "It comes automatically."

After complete spinal cord injury, messages from the brain cannot reach the nerves. Other researchers have tried to help paralysed patients walk by stimulating nerves through the back of the spine, using broad electrical fields emitted by implanted devices originally designed to control chronic pain, Courtine said.

Courtine and Bloch and their team redesigned the devices so that electrical signals would enter the spine from the sides instead of from the back. This approach allows very specific targeting and activation of spinal cord regions, Courtine said.

They then devised artificial intelligence algorithms that instruct electrodes on the device to emit signals to stimulate, in the proper sequence, the individual nerves that control the trunk and leg muscles needed for various activities such as getting up from a chair, sitting down and walking.

The software is tailored to each patient's anatomy, Courtine said.

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