Despite efforts to improve accessibility to the pillars of daily life — public transit, offices, and government buildings — for those who live with partial or total paralysis, navigating these experiences is often a struggle. Scientists in France are hoping to make that process a little easier with a mind-controlled exoskeleton suit.
A paper on the advancement was published this week in the journal Lancet Neurology, and describes a two-month study in which researchers used a minimally invasive surgery to implant two computers onto the surface of a brain of a person living with tetraplegia.
These computers allowed the patient, a now 30-year-old man who had lost movement in all four limbs following an accident, to move the exoskeleton by simply thinking about the movement and triggering neural activity which the computers synthesized and relayed to the suit as yes or no movement cues.
“I felt like the first man on the moon,” the patient told New Scientist. “I hadn’t walked for two years. I had forgotten that I used to be taller than a lot of people in the room. It was very impressive.”
How they developed the suit
But, before he could walk, the patient first tested the exoskeleton on less-complicated tasks, like controlling the movements of an avatar in a video game simulation or testing his rotation capabilities in a 2D plane. When comparing the patient’s successes to his total number of attempts, the study found that he had a success rate of 82.5 percent when walking in the video game.
When moving to the exoskeleton, that success rate dropped to 71 percent. The suit itself was also not totally self-reliant, as it was tied to the ceiling.
Despite being attached to the ceiling, throughout 39 different sessions and by taking 480 steps, the patient was able to walk a total of 145 meters (roughly 476 feet) using the suit.
Researchers say that in future iterations of this study they hope to improve the independent balance of the suit itself.
Now, this kind of exoskeleton is certainly not the first of its kind, but the researchers say their research is the less invasive than previous efforts by others.
The surface-level implementation strategy not only helped prevent infection in the patient, but also kept the computers functioning longer because they weren’t hindered by other cell growth. Additionally, the wireless nature of these implants also allowed the researchers to focus on more than a single limb at a time, opening the study up for tetraplegics for the first time.
While the results of the study were promising, the authors stress that this approach is still far from entering clinical or home settings. In addition to working with more patients, future research will also need to focus on improving the balance and mobility of the suit itself.
Before fully-functioning exoskeletons become a reality, study author Stephan Chabardes, neurosurgeon from the CHU of Grenoble-Alpes, says he hopes this approach could be adapted for wheelchair mobility control in the shorter-term.
“Our findings could move us a step closer to helping tetraplegic patients to drive computers using brain signals alone, perhaps starting with driving wheelchairs using brain activity instead of joysticks, and progressing to developing an exoskeleton for increased mobility,” said Chabardes.
Approximately 20% of traumatic cervical spinal cord injuries result in tetraplegia. Neuroprosthetics are being developed to manage this condition and thus improve the lives of patients. We aimed to test the feasibility of a semi-invasive technique that uses brain signals to drive an exoskeleton.