When the implant is switched on, he can walk for about half a mile say the researchers.
In two studies published today in the journals Nature and Nature Neuroscience, scientists have shown that targeted electrical stimulation of the spinal cord, combined with intense physical rehabilitation, enabled these paraplegic patients to recover their leg movement and eventually start walking again.
There were three of the total paralyzed men who were told that they wouldn't be able to walk again in their lives and they would spend the rest of their lives by simply being in wheelchairs.
"Selected configurations of electrodes are activating specific regions of the spinal cord, mimicking the signals that the brain would deliver to produce walking", she said. And so the researchers set about understanding how the nervous system responded to movements in every joint in healthy individuals, building up a "map" of what these activation patterns looked like.
By the end of the study, the paralysed study participants could walk, with the help of bodyweight support, for over a kilometre on a treadmill thanks to the electrical spinal cord stimulation.
The University of Technology Sydney will have a research centre capable of administering this treatment in trials within the next year, according to Professor Vissel. Because it disrupts the connection between the brain and the spinal cord, injuries can lead to motor and sensory deficits or, sometimes, paralysis. Walking actually came in fourth, behind sexual function, bladder and bowel movement, and the ability to control body posture. After a few months, participants regained voluntary control over previously paralysed muscles without stimulation and could walk or cycle in ecological settings during spatiotemporal stimulation. "It doesn't need the brain to walk", Oxley said.
Gert-Jan Oskam, who lost the use of both his legs in a cycling accident, had also made very limited progress in rehabilitation before the study.
For Courtine, Bloch, and their colleagues, the next step is to explore results in people with recent injuries, where "the potential for plasticity is elevated and the neuromuscular system has not yet undergone the atrophy that follows chronic paralysis", they write. "In our method, we implant an array of electrodes over the spinal cord which allows us to target individual muscle groups in the legs", said study author and CHUV neurosurgeon Jocelyne Bloch, who surgically placed the implants in the patients. 'Two of them can walk long distances with crutches, ' he adds.
The stimulation begins with a pulse directed at a muscle to prompt the patient to begin movement, for example a step.
The advance offered by this study is a "real breakthrough" in terms of restoring mobility to some paralyzed patients, even though they likely won't achieve fully independent walking, Oxley said.