A man mostly paralyzed from the shoulders down has spent the last two years working with researchers to control an exoskeleton with his mind.

On Thursday, researchers at the University of Grenoble released results of the trial (funded by Clinatec), saying the work indicates that operating a four-limb robotic system could be feasible for patients with tetraplegia (loss of control of all four limbs). In the most complex use of the system, the patient, a 28-year-old french man identified as Thibault, walked.

The system is far from a patient-ready solution. Instead, the researchers' and patient's work training the algorithm that interprets brain signals and turns them into physical movement, indicates that technology like this is possible.

"Ours' is the first semi-invasive wireless brain-computer system designed for long term use to activate all four limbs," Professor Alim-Louis Benabid, president of the Clinatec Executive Board, a CEA laboratory, and Professor Emeritus from the University of Grenoble, France, said in a press release.

Thibault suffered a cervical spine injury that left him without control of his legs. He retained some movement in his biceps and left wrist, so he's been operating a wheelchair with his left arm.

To let him control something external through brain signals, researchers implanted two sensors between the patient's skin and brain (not in the brain itself). The sensors were able to record brain activity in the sensorimotor cortex, the part of the brain that controls movement and sensation.

Researchers noted that other studies have implanted chips and sensors directly into the brain, and kept them connected to computers with wires. By contrast, this study's sensors were less invasive, and connected wirelessly.

The next step was to train an algorithm to interpret the signals, and translate them into movement. The patient did this by playing a game similar to Pong, where he moved a platform left or right to catch a digital ball. He also practiced more complex movements, like reaching out a hand, and turning a wrist, through a virtual simulation.

That work in the digital realm enabled training on a mechanical exoskeleton with 14 moveable joints. He began by moving the arms of the machine to touch various levers.

Finally, Thibault was able to walk with the exoskeleton. The machine was still attached to the ceiling for stability, and cannot give the balance (or "equilibrium") required for walking on one's own. But the complex movement demonstrated the ability to control the skeleton with one's mind.

Researchers say the technology could hold promise for patients to perhaps operate their wheelchairs through their brains.

"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," Professor Stephan Chabardes, neurosurgeon from the CHU of Grenoble-Alpes, said.

This futuristic treatment doesn't mean that paralyzed people will be able to walk on their own in the near future. But Thibault's walk is a step in that direction.