Thanks to a team of UC Irvine researchers and biomedical engineers, a paralyzed man has now regained the ability to walk without the use of robotic limbs.
Led by UC Irvine biomedical engineer Zoran Nenadic and neurologist An Do, researchers managed to design an innovative brain-computer interface that allows brain waves to bypass the spinal cord in order to travel to specific areas of the body.
This new interface has allowed 26 year-old Adam Fritz, with complete paralysis in both legs due to a spinal chord injury, to walk along a 12-foot course last Thursday.
“Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking,” explained Nenadic, associate professor of biomedical engineering in a press release. “We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury.”
The new interface functions using an electroencephalogram-based system that takes electrical signals from the brain, processes them through a computer algorithm and then sends them to flat metal discs. These discs, known as electrodes, are placed around the knees to receive and relay the trigger for movement in the muscles.
However, in order to reach the stage where he could take his first steps, Fritz underwent months of mental and physical training to reactivate the brain’s walking capability.
Throughout the early stages of his therapy process, Fritz was asked to think about moving his legs while wearing an electroencephalogram cap. The brain waves were then sent to the algorithm in order to identify those specifically related to leg and muscle movement. During the final stages, Fritz controlled an avatar in a virtual reality environment in order to confirm the brain waves determined by the computer algorithm.
This process generated a custom design so that when Fritz wanted to move the algorithm could process the brain waves, specific to the participant, into signals that could stimulate his legs.
The participant’s mental therapy was highly dependent on his physical condition and strength in his leg muscles, however.
Wearing the electroencephalogram cap, Fritz practiced walking suspended 5 centimeters above the floor in order to move his legs without having to support himself. After successfully honing his movement, the participant then practiced on the ground, wearing a support system and frequently pausing to prevent falls.
“Once we’ve confirmed the usability of this noninvasive system, we can look into invasive means such as brain implants,” said Do, an assistant clinical professor of neurology in a press release. “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 his legs.”
The team of researchers and engineers at UCI believe this new interface is the first step of many to come in assisting those affected by paralysis caused by spinal cord injury, stroke and amyotrophic lateral sclerosis (ALS).
