For many years people have imagined that paralysis after spinal cord injury was irreversible. But recent research shows that neurotechnology delivering electrical stimulation directly to the spinal cord may enable people with paraplegia to walk again. Research undertaken at EPFL in Switzerland has given the most encouraging results so far, applying the results of animal experiments to three patients.
After several months of training with electrical stimulation our three participants were able to activate their previously paralysed muscles without electrical stimulation. They could even take a few steps over ground, hands free, without any support. For me, seeing this recovery was amazing.
Instead of applying continuous electrical stimulation as similar projects in the US have done, the Swiss team developed targeted electrical stimulation that activated the spinal cord more precisely. This means that trains of electrical pulses are delivered at specific locations in order to mimic how the brain normally activates the spinal cord. Within a few weeks, this precision allowed hands-free walking in people who had sustained spinal injury more than four years ago. An electrode array connected to a pulse generator is surgically implanted over the region of the spinal cord that controls leg muscles.
So this surgery needed to be very precise in order to target all the muscles of the legs.
The timing of the stimulation is controlled in real time to coincide with the intended movement of the legs. Voluntary leg movements stop as soon as the electrical stimulation is turned off but resume immediately when the stimulation is turned on again.
One of the key moments, I would say, was when I started walking hands free on the treadmill. A lot of body weight support, but really letting the bars go. And one, two, three steps without using my hand was really crazy, because I just couldn't do it before.
Yeah, yeah, three steps!
All of our participants regained control over their paralysed muscle, but they still walked a lot better with the electrical stimulation which compelled us to develop a very practical technology that they could use in their everyday life.
A watch that responds uniquely to their own voice allows each participant to switch the stimulation on and off. Wireless technologies control the timing of the electrical stimulation, enabling the individuals to walk freely in settings outside the research lab. Three participants were involved in the study, and they are all regaining some autonomy.
The next step is to start earlier, just after the injury, when the potential of recovery is much larger.
A total of eight paraplegic patients will take part in the current EPFL study. Then a follow up is planned with 20 people who will receive more sensitive spinal implants plus a new implant in the motor cortex. We are poised to take a giant leap forward in the treatment of what was until very recently considered incurable paralysis.