Brain-machine interface allows paralysed person to walk

Neuroscientists and neurosurgeons from EPFL, CHUV, and UNIL in Switzerland, and CEA, CHUGA and UGA in France published their achievements in Nature, explaining how they were able to restore communication between the brain and spinal cord with a wireless ‘digital bridge’.

The study details how Gert-Jan, a 40-year-old man suffering from a spinal cord injury at the level of the cervical vertebrae following a bicycle accident which left him a paraplegic, was able to regain natural control of the movement of his legs through the new technology.

He was able to stand, walk and climb stairs, adding that the breakthrough allowed for rediscovery of simple pleasures that represent important change in his life.

To establish the digital bridge, two types of electronic implants were necessary. Neurosurgeon Jocelyne Bloch, professor at CHUV, UNIL and EPFL said that WIMAGINE devices, developed by French lab CEA, were implanted above the region of the brain responsible for leg movements.

The device makes it possible to decode the electrical signals generated by the brain when we think of walking, the team explained. At the same time, a neurostimulator connected to a field of electrodes was positioned over the region of the spinal cord that controls leg movement.

Guillaume Charvet, head of the BCI program at the CEA, added: “Thanks to algorithms based on adaptive artificial intelligence methods, movement intentions are thus decoded in real time from brain recordings.”

These intentions are then converted into electrical spinal cord stimulation sequences, which in turn activate the leg muscles to achieve the desired movement. This digital bridge operates in wireless mode, allowing the patient to move around independently.

According to researchers, by training diligently to walk using his digital bridge, Gert-Jan gradually recovered neurological functions that he had lost since his accident. The researchers were able to quantify ‘remarkable improvements’ in his sensory and motor abilities, even when the digital bridge was deactivated. This digital repair of the spinal cord suggests that new nerve connections have been formed.

At this stage, the digital bridge has only been used to improve walking in a paraplegic person. Bloch and Grégoire Courtine, professor of neurosciences at EPFL, CHUV and UNIL said that, in the future, an identical strategy could be used to restore the function of the arms and hands. They added that the digital bridge could also apply to other clinical indications, such as paralysis caused by stroke.

The ONWARD Medical company in collaboration with EPFL and CEA has received support from the European Commission through its European Innovation Council to develop a commercial version of the digital bridge with the objective of making this technology available worldwide.