Victory Over ParalysisUniversity of Louisville

Four paralysed individuals have voluntarily and independently moved their legs for the first time since injury, thanks to a spinal implant that delivers electrical stimulus.

"The belief that no recovery is possible and complete paralysis is permanent has been challenged," Susan Harkema, one of the University of Louisville professors behind the breakthrough, declared.

The incredible results have been published in the journal Brain, and tell the story of four men -- Kent Stephenson, Andrew Meas, Dustin Shillcox and Rob Summers -- all of whom received their life changing injuries in vehicle accidents in their 20s. Now, you can fast forward in the embedded video to about 03.45 to watch Stephenson lift his legs in a series of remarkable clips. The entire revelation of the technique, and its results, is probably best articulated by his smile, delivered whilst telling the camera: "Once you're not able to stand on your legs and go so long not being able to stand up by yourself, then you have the stimulator and you turn it on and you just stand up on your own, and it's just like... I'm standing."

"I feel like we've conquered a lot of things people thought were impossible."

Each of the four men received an epidural implant that delivers currents that mimic signals from the brain. They work in a similar way to myoelectric prostheses, which are grafted on to remaining nerves in the muscles and stimulate these to control movement. In these cases, those wearing the prosthetic can actually move the artificial limb voluntarily, just by thinking about it, because those salvaged nerves are still receiving information from the brain.

In this latest study, the candidates could voluntarily move their limbs immediately. This has led to knock-on improvements in their health, from an increase in muscle mass to a reduction in fatigue and stabilising of blood pressure levels.

"I've got a lot of function back, including my hands, I've gotten back my ability to stand, move my toes, ankles, knees, hips, all on command," says Summers. "I've gotten back a very good sensation of feeling as well as the other things people don't think about -- bladder function, bowel function, sexual function, the ability to sweat."

Each recovered and managed to make use of the system so rapidly, it's speculated that more parts of the nervous system remained intact than previously thought. Not only this, but as the four candidates continued through their training, they needed lower and lower electrical frequencies to instigate movement -- the neural pathways were improving and building off of that stimulus to create better routes. They are retraining the spinal cord to think differently.

"This is a wake-up call for how we see motor complete spinal cord injury," said V. Reggie Edgerton of UCLA's neuromuscular research laboratory. "We don't have to necessarily rely on regrowth of nerves in order to regain function. The fact that we've observed this in four out of four people suggests that this is actually a common phenomenon in those diagnosed with complete paralysis.

He adds: "The circuitry in the spinal cord is remarkably resilient. Once you get them up and active, many physiological systems that are intricately connected and that were dormant come back into play." This is something Mark Pollock, who was left paralysed after a fall in 2010, has spoken to about in the past. He has been training using Ekso Bionics exoskeletons, in the hope that the physical act of moving actually stimulates the neural pathways to recover and rebuild.

"Two of the four subjects were diagnosed as motor and sensory complete injured with no chance of recovery at all," commented Claudia Angeli, an assistant professor at University of Louisville's Kentucky Spinal Cord Injury Research Centre (KSCIRC) and author on the paper. (The other two have some sensation, but cannot move their legs.)

"Because of epidural stimulation, they can now voluntarily move their hips, ankles and toes. This is groundbreaking for the entire field and offers a new outlook that the spinal cord, even after a severe injury, has great potential for functional recovery."

The aforementioned movements were made possible because the implant targets the concentration of nerves located at the lumbosacral spinal, which are connected to the hip, knee, ankle and toes. The electrical impulses target specific regions related to specific movements, using different frequencies.

Summers was 20 years old when he was hit by a car in his own driveway, leaving him paralysed from the C6 vertebrae (in the neck) down. The former college baseball player was the first to receive the experimental implant in 2009. He achieved voluntary movement seven months after implantation.

From the successes seen during that trial, the team from the University of Louisville, UCLA and the Pavlov Institute of Physiology decided to trial it with the three other young men.

The fact that all four men, despite their varying degrees of paralysis, were able to start moving their limbs with "relatively fine voluntary control" (they were able to control the force of the movement), demonstrates that Summers' response in 2009 was not an "anomaly", say the researchers. It provides hope that this is a replicable technique for improving quality of life without damaging those nerves left viable.

The team is cautiously optimistic, but the results are truly groundbreaking. As Susan Howley, executive vice president for research at the Christopher and Dana Reeve Foundation, which partially funded the study, points out: "At the present time, other than standard medical care, there are no effective evidence-based treatments for chronic spinal cord injury. However, the implications of this study for the entire field are quite profound, and we can now envision a day when epidural stimulation might be part of a cocktail of therapies used to treat paralysis."

The results are profound not just for their obvious benefits, but for the overall improvements they can bring to a subject's life. For instance, the immobility that goes hand in hand with these types of injuries affects all manner of other health issues, including cardiac health. The fact the four subjects have already seen improvements in muscle mass and blood pressure hints at what incredible therapeutic and rehabilitation properties the implant can have. And if the promises made by the team in the embedded video are anything to go by, they don't want to keep this to a corner in California -- they want to take this global, and train scientists and doctors worldwide how to replicate the results. 

The Mark Pollock Trust is specifically designed to find and connect people working in the field worldwide, to fastback the path to a cure, and Pollock, a director at the Christopher and Dana Reeve Foundation, told the work is "a genuinely exciting breakthrough".

"Last year I was starting to learn of this work and met the scientists involved. And, at that time we stressed there were no cures or therapies for paralysis. But now there is tangible evidence that victories over paralysis will be possible for a large group of people with spinal injuries in a relatively short timeframe. This is a genuinely exciting break-through."

UK Spinal Charity Aspire commented that whilst it is "excited by the developments", we're still a long way off being able to repair the original damage done to the spinal cord in these instances. "This research, and indeed the many other studies currently taking place, is unlikely to soon lead to treatments that will make a genuine difference to the day to day lives of the 40,000 spinal cord injured people living in the UK. Until that happens, Aspire will be there to provide the practical support and advice that gives those with spinal cord injuries the independence most of us take for granted."


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