University of Houston

What if people who are paralyzed could use their brainwaves to get up out of wheelchairs and walk away? That's exactly what researchers from the University of Houston are hoping to accomplish with the latest evolution of robotic exoskeletons. They're turning to mind control to move these high-tech mobility machines to the next level -- and take patients with them.

The idea for for a mind-controlled robotic exoskeleton came to engineering professor Jose Contreras-Vidal, the project's lead, after Duke University's Miguel Nicolelis demonstrated that electrode arrays implanted in monkey brains could pick up on the neuron-firing patterns that occur when the monkey thinks about walking.

"Contreras-Vidal's group found out they could get the same effects using EEG (electroencephalography) to control an exoskeleton. EEG doesn't have the spatial resolution of an implanted electrode array, but it is noninvasive and has the added benefit of being able to measure electrical activity across the entire brain," Popular Mechanics reported.

The team created NeuroRex by modifying a Rex Bionics exoskeleton with an EEG cap that reads the brain's electrical activity.

To operate the Rex, users must have adequate body strength and functionality to transfer themselves from their wheelchair into the exoskeleton by holding on to Rex's legs. They then strap themselves in and use a hand-controlled joystick and control pad to maneuver the battery-powered mobility-assist device on solid, stable surfaces. NeuroRex aims to eliminate the need for hand controls, simply letting users, including those paralyzed from the neck down, maneuver using mental directions.

To use the NeuroRex, "the patient thinks an instruction, such as 'turn left.' The EEG electrodes pick up on the specific pattern of brain activity associated with that command and wirelessly sends the information to a computer, which interprets the data and relays a corresponding instruction to the patient's robotic legs," Popular Mechanics explained.

Clinical trials of the NeuroRex are set to begin in January, and "if all goes well, it will be on its way to becoming the first thought-controlled exoskeleton," according to the publication.

Rex Bionics

While the NeuroRex exoskeleton has promising mind-controlled applications for those paralyzed from spinal cord injuries, patients will still need to undergo rigorous training before they will be able to abandon their wheelchairs.

"NeuroRex has been tested in two people with spinal cord injury, and the upcoming study will broaden that number to about 25," Popular Mechanics reported.

"Training begins with a 5-minute session wherein the user thinks about a set of instructions, such as 'move forward' or 'turn right.' The EEG reads those patterns and learns to recognize them. Although the user can operate the robot for just a few minutes, the human-machine interface is refined over several months of training."

While NeuroRex is testing the boundaries of mind over matter, other exoskeletons already rely on motors and sensors to get patients walking again.

These mobility machines include the ReWalk from Israel's Argo Medical Technologies; suits from Rex Bionics out of New Zealand; eLegs from Berkeley Bionics; the Indego Exoskeleton, created by researchers at Vanderbilt University and engineers at Parker Hannifin; and the Ekso, from Ekso Bionics.