In a world first, electronic implants developed by Swiss and French experts have allowed a paralysed man to walk again simply by thinking about it.
The patient, 40-year-old Gert-Jan Oskam from the Netherlands, lost the use of his legs more than a decade ago after suffering a spinal cord injury in a bike accident in China.
"When he woke up he had no control over any of his movements," says Dr Henri Lorach, head of the Brain Spine Interface Unit in Lausanne Hospital, who played a key role in the remarkable medical trial.
"Over time Gert-Jan regained some mobility, notably in his hands, but it was impossible for him to walk. He contacted us in 2017 and took part in our trial in Switzerland," Lorach told RFI.
Lorach worked with other experts in Switzerland, as well as researchers from France's Atomic Energy Commission (CEA), to develop new technology to link the brain and the spinal cord.
Gert-Jan can now walk "naturally" over difficult terrain and even climb stairs, according to a case study published this week in the journal Nature.
The breakthrough has given the Dutchman "a freedom" he did not have before, he told a press conference in Lausanne on Wednesday.
'Digital bridge'
The latest research is based on electronic implants – one in the brain and the other around the spinal cord.
Gert-Jan had them fitted in an operation carried out by Professor Jocelyne Bloch of Lausanne University in July 2021.
The two implants build what the researchers call a "digital bridge" – re-establishing the connection lost during his accident.
Sensors on his head wirelessly transmit his brain signals, intentions to move, from the implant to a portable computer that is small enough to be worn in a small backpack.
The interface, designed by researchers at the CEA, uses algorithms based on artificial intelligence methods to decode those brain signals in real time.
The data is then transmitted to the spinal cord implant in the form of electrical signals that in turn instruct the leg muscles to move as desired.
While spinal implants have already allowed some patients to walk again, they require them to activate each motion by pressing a button – unlike the new system.
"Now I can just do what I want – when I decide to make a step the stimulation will kick in as soon as I think about it," Gert-Jan said.
He told journalists it had been "a long journey to get here".
But among the "simple pleasures that represent a significant change," he highlighted being able to stand at a bar again with friends and have a beer.
'Real step forward'
The device took three years to develop, but is the culmination of decades of previous technological research, says Lorach.
"It's a real step forward and shows we can make the control [of the muscles] voluntary."
Gert-Jan wears the device around an hour a day to walk unattended. Another positive sign, Lorach says, is that "through this training, the patient has recovered some of the capacities he had lost in the accident".
The device has its limits though – it's bulky, expensive and many more years of research are needed for it to be widely available.
The team learned a lot from the six months Gert-Jan stayed in the Lausanne hospital.
"We now have a much better idea of how to calibrate the system, how to optimise it. Thanks to this trial we'll be able to reduce the cost and offer it to more people," Lorach says.
The aim is now "to reduce the size, and increase the usability for patients so it can be used 24/7 by everyone".
