Doctors say he is the first patient with paraplegia caused by spinal cord injury to walk without the aid of robotic limbs that are controlled manually.
“Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking,” Zoran Nenadic, one of the researchers from the University of California, explained. “We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury."
The system works via non-invasive electroencephalography (EEG), where the participant wears a cap that captures electrical signals generated by the brain. These are then processed by a computer algorithm and transmitted to electrodes attached to the subject’s knees, triggering movement in the leg muscles.
The volunteer had to undergo months of mental training to reactivate his brain’s conceptual walking ability, in addition to extensive physical therapy that enabled him to begin moving his legs again.
The mental training consisted of the man wearing the EEG cap that read his brain waves as he was being instructed to think about walking. Software processed his thoughts and isolated the brain waves associated with leg movement.
This progressed to the man using his thoughts to control the walking of a virtual reality avatar, before physical training commenced. The man first practised walking while suspended in the air, before finally standing on his own two feet, culminating in him walking nearly 4m across the ground.
As the interface was custom-designed to suit the volunteer’s particular brain waves, the team behind the research says further research will be needed if they want to achieve similar results for others.
“Once we’ve confirmed the usability of this non-invasive system, we can look into invasive means, such as brain implants,” Nenadic said. “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.”
