A brain-to-computer technology that can translate thoughts into leg
movements has enabled a man paralyzed from the waist down by a spinal
cord injury to become the first such patient to walk without the use of
robotics, doctors in Southern California reported on Wednesday.
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 metres (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
paralysed patients to grasp a cup of coffee with a robotic arm and raise
the beverage to their mouths.
The latest study, which began about
five years after Fritz became paralysed, involved months of mental
training in which he practised 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.
© Thomson Reuters 2015