Using only his brain signals, a paralyzed French man was able to operate, maneuver, and walk in a whole-body robotic exoskeleton. While the four-limb system isn’t ready for clinical applications yet, and will require improvements before that point, researchers call the early results “promising” in a press release.
Some might call them astonishing.
The man, who suffers from tetraplegia, also known as quadriplegia, moved all four of his paralyzed limbs using his brain. Researchers emphasize the experimental nature of their work.
“Ours’ is the first semi-invasive wireless brain-computer system designed for long term use to activate all four limbs,” says Alim-Louis Benabid, President of the Clinatec Executive Board, a CEA laboratory, and Professor Emeritus from the University of Grenoble, France, in the press statement. “Previous brain-computer studies have used more invasive recording devices implanted beneath the outermost membrane of the brain, where they eventually stop working. They have also been connected to wires, limited to creating movement in just one limb, or have focused on restoring movement to patients’ own muscles.”
After an accident in a night club, the French man, identified only as Thibault, 28, from Lyon, suffered a cervical spinal cord injury. One out of every five cervical spinal cord injuries results in having all four of the body’s limbs partially or totally paralyzed. After Thibault’s accident, he only maintained some movement in his biceps and left wrist. Using his left arm, he was able to operate a wheelchair.
Preparing for his exoskeleton, Thibault had two recording devices implanted, one on either side of his head between the brain and skin. This allowed for the devices to tap into the sensorimotor cortex, which controls sensation and motor function.
The prep work for the exoskeleton took 24 months. During that time, Thibault had to undergo a number of tests. These started with simple mental tasks, training the team’s algorithm to understand his thoughts. The tasks included controlling a virtual avatar within a video game similar to the classic Pong. He would then reach for targets within the game, and the exoskeleton would reach with him.
Progress was measured by how many degrees of freedom Thibault was able to achieve during tasks. These started out with small movements, like flipping a brain-powered switch. Gradually, they moved on to more complex tasks, like walking and picking up objects.
The exoskeleton’s 14 joints and 14 degrees of freedom allowed Thibault to move his body in 14 different ways. During testing, he spent 45 days operating the exoskeleton and 95 training at home with the Pong-like game and a researcher by his side.
When training to turn on the brain-powered switch, work began rapidly. Just two months after surgery, Thibault was successful 73 percent of the time in turning on the switch during six sessions using the exoskeleton.