Scientists have successfully tested a brain-controlled exoskeleton on a man with four paralyzed limbs—though they caution the breakthrough is in very early stages. A French team published the results of a two-year trial in The Lancet and unveiled a video that showed the tetraplegic patient walking with the help of a ceiling-mounted harness and the robotic apparatus. Electrodes implanted in his head collected brain signals, sent them to a decoding algorithm, which transmitted instructions to the whole-body exoskeleton, and to a video-game avatar. Between the avatar and the exoskeleton, he was able to take 480 steps over the course of 39 sessions. The researchers said their next challenge is figuring out how to give a patient enough equilibrium so the exoskeleton will work without a harness. They also noted that they are far from clinical application, cautioning against a “danger of hype.”