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 The slow, halting first steps of the 28-year-old paraplegic were
documented in a preliminary study published in the British-based
Journal of NeuroEngineering and Rehabilitation, along with a YouTube
video.
The feat was accomplished using a system allowing the 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.
Researchers at the University of California, Irvine, say the outcome
marks a promising but incremental achievement in the development of
brain-computer interfaces that may one day help stroke and spinal
injury victims regain some mobility.
Dr. An Do, a study co-author, said clinical applications were many
years away. Results of the UC Irvine research still need to be
replicated in other patients and greatly refined.
 Nevertheless, the study proved it possible "to restore intuitive,
brain-controlled walking after a complete spinal cord injury," said
biomedical engineer Zoran Nenadic, who led the research.
The steps taken a year ago by the experiment's subject, former
graduate student Adam Fritz, who injured his back in a motorcycle
accident, appear modest as seen in the video.
Fritz propelled himself over a distance of 3.6 meters (11.8 feet)
across the floor of UC Irvine's iMove Lab, though his weight was
partially supported by an overhead suspension harness and a walker
he grasped to keep his body upright, researchers said.
The weight support was necessary because the patient lacked any
sensation in his legs or feet, Do explained.
Still, the experiment built on earlier UC Irvine studies in which
brain signals were transmitted to a robotic prosthesis attached to
the patient's legs to produce movement, Do said. In previous
research by other scientists, a brain-computer interface has been
used to allow paralyzed patients to grasp a cup of coffee with a
robotic arm and raise the beverage to their mouths.
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The latest study, which began about five years after Fritz became
paralyzed, involved months of mental training in which he practiced
thinking about walking to produce necessary leg-moving brain waves.
Those 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 scientists and patient first practiced with a
virtual-reality-like video game in which Fritz was trained to
control a walking avatar. He also underwent extensive physical rehab
to strengthen his muscles.
Fritz next practiced walking in the actual lab while suspended
slightly above the floor. On his 20th outing, he finally took his
first real steps on the ground.
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.
(Reporting by Steve Gorman; Editing by Eric Beech)
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Brain-computer
link enables paralyzed California man to walk
