A 26-year old paralyzed man was able to walk for the first time in 5 years, using a computer which acted as an intermediary between his brain and his limbs.
Experts from the University of California, Irvine, devised a process which allows brain waves to be transmitted via an electroencephalogram (EEG) electrode cap placed on the patient’s head. The signals are received by a computer, where a program runs a set of algorithms which establish if the wearer wants to walk or remain standing.
The commands are then conveyed to micro-controllers, which carry signals to nerves, that activate leg muscles, causing contractions. Basically, messages from the brain are rerouted to the knees, by employing a computer interface.
The experiment was published today in the Journal of NeuroEngineering and Rehabilitation. In the initial stage, the patient, who had sustained a spinal cord injury that left wheelchair-bound, completed a 20-week training course, allowing him to gain more muscle tone in his legs, and to control his brain functions more accurately.
Throughout his practice, he learned how to send the appropriate neural signals that would cause an avatar to advance through a virtual environment. At first, he had up to 70% control of the device, but by the end of the training he achieved 99% accuracy.
The trial was proven successful: the man, despite being paralyzed from the waist down, was able to walk for 3.5 meters. He was aided just by a walking frame and a harness, just in case he fell, but that never happened. Overall, his thoughts allowed him to control his limbs 99% of the time, causing them to stop or move whenever he wished.
This is the first time that a paraplegic person was given the chance to move without the assistance of manually-operated robotic exoskeleton.
According to researchers, the proof-of-concept study is extremely promising, because it is a marked improvement on current brain-controlled systems, which require the presence of bionic limbs or a virtual reality interface.
“Even after years of paralysis, the brain can still generate robust brain waves that can be harnessed to enable basic walking”, declared neurologist An Do, co-leader of the study.
Although the experiment proves that electronic devices can be used to bypass problem areas and allow the brain to execute movements, scientists insist that more research has to be conducted.
So far, the limitation of the experiment was that balance and stabilization weren’t completely accurate, and a greater number of patients have to be analyzed before it can be established that the technique is ready to be implemented on a wider scale.
In addition, experts are trying to devise a way to incorporate the system in the patient’s brain, and remove the necessity of an external computer.
Worldwide, between 250,000 and 500,000 people suffer spinal cord damage every year, which leaves them partially or complete paralyzed.
“A fully implantable brain-computer interface system” placed beneath the skull may be invented, which would give such patients not just the chance to walk again, but also complete freedom of movement.
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