A paralysed man has been restored the use of his legs courtesy of a computer interface that translates brain signals into leg movements.
In the first successful implementation of its type, the technology is able to translate thoughts into leg movements without the use of robotics.
Former 28-year-old graduate student Adam Fritz (pictured above) injured his back in a motorcycle accident, resulting in paralysis from the waist down.
The computer system allows Fritz's brain to bypass the injured spinal cord and instead send messages through a computer algorithm to electrodes placed around the patient's knees to trigger controlled leg muscle movements.
Although Fritz is currently only able to walk a short distance with a mechanical aid, researchers at the University of California have said the technology represents a promising yet incremental achievement in the development of brain-computer interfaces.
With further development the researchers hope that stroke and spinal injury victims could regain some mobility.
Dr. An Do, co-author on the study, said clinical applications were many years away and the results of the research still need to be refined and replicated in other patients.
The study was published in the British-based Journal of NeuroEngineering and Rehabilitation along with a Youtube video (below) showing Fritz’s progress.
The video shows Fritz propelling himself over a distance of 3.6 meters across the floor of the research lab with his weight being partially supported by an overhead suspension harness and a walker he grasped to keep his body upright.
The weight support was necessary because the patient lacked any sensation in his legs or feet, Do explained.
The study took place five years after Fritz’s accident and involved months of mental training in which he practiced thinking about walking to produce the necessary leg-moving brain waves.
The signals were then picked up by an electroencephalogram (EEG) he wore as a cap and were transmitted to a computer for processing by a special algorithm that could isolate the messages related only to leg motion and convert them to signals that would stimulate the patient's muscles to walk.
The patient initially practised with a virtual-reality video game in which he was trained to control a walking avatar and also underwent extensive physical rehab to strengthen his muscles.
Researchers hope to refine the technology by miniaturizing the EEG component enough to be implanted inside the patient's skull or brain, allowing for clearer reception of the neural messages and perhaps the delivery of pressure sensation from sensors in the foot back to the brain.
The research follows previous studies by other scientists on brain-computer interfaces. In the past, paralyzed patients have been able to grasp a cup of coffee with a robotic arm and raise it to their mouths.