IRVINE, Calif., Sept. 24 (UPI) -- A man's ability to walk using direct brain control of his legs was restored after years of being paralyzed, researchers reported in a proof-of-concept study.
The system uses electrical signals from the man's brain, sending them to electrodes placed on his knees, allowing him to voluntarily move his legs.
Previous research has shown paralysis patients can be made to move their legs with noninvasive treatments, however this study used virtual reality training and a harness system, rather than an exoskeleton to help the man support his weight.
"Even after years of paralysis the brain can still generate robust brain waves that can be harnessed to enable basic walking," said Dr. An Do, a researcher at the University of California Irvine, in a press release. "We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury. This noninvasive system for leg muscle stimulation is a promising method and is an advance of our current brain-controlled systems that use virtual reality or a robotic exoskeleton."
Previous research at the University of California Los Angeles showed a method of placing electrodes along five patients' legs allowed them to make walking motions using their brains.
The same UCLA researchers combined the electrode method with an exoskeleton and physical training to help a man take thousands of steps while wearing an exoskeleton that assisted his movements.
The 26-year-old man in the UC Irvine study was trained to use a brain-computer interface, or BCI, for several weeks first by visualizing the act of walking in his mind, and then by using a virtual reality environment which allowed him to control an on-screen avatar with the help of an electroencephalogram, or EEG.
The BCI is accomplished using an EEG that translates brain waves which are sent to a functional electrical stimulation, or FES, system of electrodes on the man's legs. The man also was given physical rehabilitation to recondition and strengthen his leg muscles.
Researchers started the man off connected to a suspension device about 5 centimeters off the ground, so he could practice moving his legs without having to support himself.
Over the course of 19 weeks, they kept the man attached to the suspension device and gave him a walker to prevent falls as he gained more ability to operate the FES system while following verbal instructions.
Researchers said the goal of testing a BCI system is to develop a brain implant that can communicate with electrodes in the legs, however researchers said a noninvasive version allows for better testing of the method.
"Once we've confirmed the usability of this noninvasive system, we can look into invasive means, such as brain implants," said Dr. Zoran Nenadic, a researcher at UC Irvine. "We hope that an implant could achieve an even greater level of prosthesis control because brain waves are recorded with higher quality. In addition, such an implant could deliver sensation back to the brain, enabling the user to feel their legs."