Twenty-fifteen has been a big year for prosthetics. We’ve seen a paralyzed man use his brain to communicate with metal arms, children build articulated limbs out of LEGO, and 3D printing lower prosthetic costs 100-fold .

There’s no denying that these robotic avatars will play a major role in the future of medicine, but what if we could override paralysis without them? For the first time in medical history, a team of scientists has successfully rerouted the neural signals from a paraplegic’s brain, allowing him to walk using his own legs.

This groundbreaking procedure marks the first time 28-year-old Adam Fritz has walked since an accident damaged his spinal cord five years ago. Developed by researchers at University of California at Irvine, the Brain-Control-Interface (BCI) uses a computer to link Frtiz’s brain and knees (over a Bluetooth connection, no less) in order to bypass the severed region of his spinal cord.

“Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking,” Dr. An Do, who co-authored the proof-of-concept study, told The Guardian.

The system isn’t exactly designed for plug-and-play – it took Fritz nearly 19 weeks to master the use of the BCI, a process that included intense physical therapy to rebuild the atrophied muscles in his legs – but his success has the team excited for the future. “He was able to maintain good control,” they say.

In order to train his brain to produce clear, readable signals, Fritz first practiced walking in a virtual world using a special electroencephalogram (EEG) cap, which monitors brain waves. You can think of this like a motion-capture suit used in filmmaking, only here, the sensors are recording the movements Fritz is thinking about, rather than actually doing.

NPCs from Half-Life 2 included? Nice.

On his 20th go, Fritz finally was given the clear to use the system for an overground walk, aided only by a suspension belt to alleviate pressure and a support frame to keep him from toppling over. Amazingly, he was able to walk the entire 3.5-meter course. While it might look like Fritz has complete control over his legs, it’s important to note that he is governing only “the general concept of walking” using two commands: start and stop.

“When the computer detects that a person is walking, based on these brain waves, it turns on the electrical stimulator, which starts creating muscle contractions in the right leg first, and then the left leg; right leg, left leg. And then it keeps on doing this automatically until he stops thinking about walking, then it shuts it off and keeps him in a standing position,” explains Do.

The next step is to test the device in a larger sample of patients, and to dream up ways of making it more precise, user-friendly, and natural. We’re more than a stone’s throw away, but Do and his team hope to see a fully-implantable BCI come to fruition over the coming years.

“Such a fully implantable system would eliminate the need to mount and unmount the equipment, such as an EEG cap, bioamplifier and a computer, thereby making it more practical and aesthetically appealing. Nevertheless, the noninvasive system presented here may become a safe test bed to determine which individuals are good candidates to receive these neuroprostheses, once they become available.”

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IMAGES: King et al., Journal of NeuroEngineering and Rehabilitation