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.
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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.
“Walking is a very fundamental behavior for us”, he said, pointing out that sitting can affect a person’s cardiovascular health or their bladder control.
A paralysed man has made medical history by walking again, using thought power – after doctors reconnected brain signals to his legs.
Once the patient has mastered this virtual walking, the next stage was to train him to use his own leg muscles for simulated walking while he was supported with his feet 5cm above the training course.
Although the patient needed 20 weeks to properly develop both the muscles and the right brain signals for the computer to interpret properly, the overall experiment worked.
Dr Do added: “This non-invasive system for leg muscle stimulation is a promising method and is an advance of our current brain-controlled systems that use virtual reality or a robotic exoskeleton”. In each session, he gained more control and completed more tests. The nerves do not grow back and often scar tissue forms at the site of the damage.
The system was not exactly plug-and-play, and the patient needed extensive training to use it, the researchers reported in the Journal of Neuroengineering and Rehabilitation.
Now that the technique has been shown to work with one patient, the researchers are looking forward to further studies involving whole groups of people suffering from paraplegia.
Researchers fitted the man first with a cap that monitors electrical signals around the rain and collects them as a computer-controlled electroencephalogram, and then applied electrodes to his knees to receive these signals.
In future, the electrode cap used in the study to record brain signals is likely to be replaced by hidden implants.
Dr Nenadic said such an implant “could deliver sensation back to the brain, enabling the user to feel their legs”. Sixty-percent of them say they would be willing to use a BCI implant if it would help them to walk. “However, independent over-ground walking is still some way off, not least because the issue of maintaining balance hasn’t yet been addressed”.
Another problem is the bulk of the system, which will need to be solved with smaller, implantable devices. The Feasibility of a Brain-Computer Interface Functional Electrical Stimulation System for the Restoration of Overground Walking after Paraplegia.
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Brian Carlin, of spinal injury charity Aspire, said it was “fantastic”, pointing out that every eight hours someone in the United Kingdom is paralysed by spinal injury.
