The present

After his success with primates, Nicolelis was eager to apply the advances in BMI to people. But there were some big challenges in the transition from lab animals to human patients, namely that many people weren’t willing to undergo invasive brain surgery for the purposes of clinical research. "There is an open question of whether you need to have implants to get really fine grained control," says Henriquez. The Walk Again Project hopes to answer that question, at least partially. While it is based on research in animals that required surgery, it will be using only external EEG headsets to gather brain activity.

The fact that these patients were paralyzed presented another challenge. Unlike the lab monkeys, who could move their own arms and observe how the robot arm moved in response, these participants can’t move their legs, or for many, really remember the subconscious thought process that takes place when you want to travel by putting one foot in front of the other. The first step was building up the pathways in the brain that would send mental commands to the BMI to restore locomotion.

To train the patients in this new way of thinking about movement, researchers turned to virtual reality. Each subject was given an EEG headset and an Oculus Rift. Inside the head-mounted display, the subjects saw a virtual avatar of themselves from the waist down. When they thought about walking, the avatar legs walked, and this helped the brain to build new connections geared towards controlling the exoskeleton. "We also simulate the stadium, and the roar of the crowd," says Regis Kopper, who runs Duke’s VR lab. "To help them prepare for the stress of the big day."

"The brain is a remarkable instrument. It has the ability to rewire itself."

Once the VR training had established a baseline for sending commands to the legs, there was a second hurdle. Much of walking happens at the level of reflex, and without the peripheral nervous system that helps people balance, coordinate, and adjust to the terrain, walking can be a very challenging task. That’s why even the most advanced robots have trouble navigating stairs or narrow hallways that would seem simple to humans. If the patients were going to successfully walk or kick a ball, it wasn’t enough that they be able to move the exoskeleton’s legs — they had to feel them as well.

The breakthrough was a special shirt with vibrating pads on its forearm. As the robot walked, the contact of its heel and toe on the ground made corresponding sensations occur along parts of the right and left arms. "The brain essentially remapped one part of the body onto another," says Henriquez. "This restored what we call proprioception, the spacial awareness humans need for walking."

In recent weeks all eight of the test subjects have successfully walked using the exoskeleton, with one completing an astonishing 132 steps. The plan is to have the volunteer who works best with the exoskeleton perform the opening kick. But the success of the very public demonstration is still up in the air. The suit hasn’t been completely finished and it has yet to be tested in an outdoor environment. The group won't confirm who exactly will be wearing the suit. Nicolelis, for his part, isn’t worried. Asked when he thought the entire apparatus would be ready, he replied: "Thirty minutes before."