Restoring Ability: Project NEUWalk

neuwalkIn the past few years, medical science has produced some pretty impressive breakthroughs for those suffering from partial paralysis, but comparatively little for those who are fully paralyzed. However, in recent years, nerve-stimulation that bypasses damaged or severed nerves has been proposed as a potential solution. This is the concept behind the NEUWalk, a project pioneered by the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland.

Here, researchers have figured out a way to reactivate the severed spinal cords of fully paralyzed rats, allowing them to walk again via remote control. And, the researchers say, their system is just about ready for human trials. The project operates on the notion that the human body requires electricity to function. The brain moves the body by sending electrical signals down the spinal cord and into the nervous system.

spinal-cord 2When the spinal cord is severed, the signals can no longer reach that part of the spine, paralysing that part of the body. The higher the cut, the greater the paralysis. But an electrical signal sent directly through the spinal cord below a cut via electrodes can take the place of the brain signal, as the team at EPFL, led by neuroscientist Grégoire Courtine, has discovered.

Previous studies have had some success in using epidural electrical stimulation (EES) to improve motor control where spinal cord injuries are concerned. However, electrically stimulating neurons to allow for natural walking is no easy task, and it requires extremely quick and precise stimulation. And until recently, the process of controlling the pulse width, amplitude and frequency in EES treatment was done manually.

brainwavesThis simply isn’t practical, and for two reasons: For starters, it is very difficult for a person to manually adjust the level of electrostimulation they require to move their legs as they are trying to walk. Second, the brain does not send electrical signals in an indiscriminate stream to the nerves. Rather, the frequency of the electrical stimulation varies based on the desired movement and neurological command.

To get around this, the team carefully studied all aspects of how electrical stimulation affects a rat’s leg movements – such as its gait – and was therefore able to figure out how to stimulate the rat’s spine for a smooth, even movement, and even take into account obstacles such as stairs. To do this, the researchers put paralyzed rats onto a treadmill and supported them with a robotic harness.

NEUWalk_ratsAfter several weeks of testing, the researchers had mapped out how to stimulate the rats’ nervous systems precisely enough to get them to put one paw in front of the other. They then developed a robust algorithm that could monitor a host of factors like muscle action and ground reaction force in real-time. By feeding this information into the algorithm, EES impulses could be precisely controlled, extremely quickly.

The next step involved severing the spinal cords of several rats in the middle-back, completely paralyzing the rats’ lower limbs, and implanted flexible electrodes into the spinal cord at the point where the spine was severed to allow them to send electrical signals down to the severed portion of the spine. Combined with the precise stimulation governed by their algorithm, the researcher team created a closed-loop system that can make paralyzed subjects mobile.

walkingrat.gifAs Grégoire Courtine said of the experiment:

We have complete control of the rat’s hind legs. The rat has no voluntary control of its limbs, but the severed spinal cord can be reactivated and stimulated to perform natural walking. We can control in real-time how the rat moves forward and how high it lifts its legs.

Clinical trials on humans may start as early as June 2015. The team plans to start testing on patients with incomplete spinal cord injuries using a research laboratory called the Gait Platform, housed in the EPFL. It consists of a custom treadmill and overground support system, as well as 14 infrared cameras that read reflective markers on the patient’s body and two video cameras for recording the patient’s movement.

WorldCup_610x343Silvestro Micera, a neuroengineer and co-author of the study, expressed hope that this study will help lead the way towards a day when paralysis is no longer permanent. As he put it:

Simple scientific discoveries about how the nervous system works can be exploited to develop more effective neuroprosthetic technologies. We believe that this technology could one day significantly improve the quality of life of people confronted with neurological disorders.

Without a doubt, restoring ambulatory ability to people who have lost limbs or suffered from spinal cord injuries is one of the many amazing possibilities being offered by cutting-edge medical research. Combined with bionic prosthetics, gene therapies, stem cell research and life-extension therapies, we could be looking at an age where no injury is permanent, and life expectancy is far greater.

And in the meantime, be sure to watch this video from the EPFL showing the NEUWalk technology in action:


Sources:
cnet.com, motherboard.com
, actu.epfl.ch

The Future of Medicine: AR Treats Phantom Limb Pain

AR_plpStudies have shown that a good deal of amputees feel pain in their lost limbs, a condition known as Phantom Limb Pain (PLP). The condition is caused when the part of brain responsible for a limb’s movement becomes idle, and thus far has very difficult to treat. But a new study suggests therapy involving augmented reality and gaming could stimulate these unused areas of the brain, resulting in a significant reduction in discomfort.

Previous attempts to ease PLP by replicating sensory feedback from an artificial hand have included prosthetics and a treatment known as mirror therapy, where a reflection of the patient’s remaining limb is used to replace the phantom limb. Virtual reality systems have resulted in more sophisticated mirror therapy, but the approach is only useful for the treatment of one-sided amputees.

Mirror TherapyA research team from Sweden’s Chalmers University of Technology sought to overcome this and achieve greater levels of relief by testing a treatment where the virtual limb would be controlled through myoelectric activity. This is a process where the muscle signals which would control the phantom limb at the stump are detected and then used to create a pattern that will predict the limb’s movements and provide the requisite stimulation.

To test the treatment, the researchers connected amputee Ture Johanson – a man who have lived with PLP for 48 years – to a computer. Electrodes running from his stump to the machine provided the input signals, and on the computer screen, he was able to see and move a superimposed virtual arm. The electronic signals from his arm communicated to the computer and his movements were simulated before his very eyes, and then used to control a car in a racing game.

plp-augmented-realityWithin weeks of starting this augmented reality treatment in Max Ortiz Catalan’s clinic at Chalmers, his found his pain easing and even disappearing entirely. Mr Johanson says he has noticed other benefits, like how perceives his phantom hand to be in a resting, relaxed position rather than constantly a clenched fist:

The pain is much less now. I still have it often but it is shorter, for only a few seconds where before it was for minutes. And I now feel it only in my little finger and the top of my ring finger. Before it was from my wrist to my little finger… Can you imagine? For 48 years my hand was in a fist but after some weeks with this training I found that it was different. It was relaxed. It had opened.

Mr Johanson has also learned to control the movements of his phantom hand even when he is not wired up to the computer or watching the virtual limb.

AR_plp1Max Ortiz Catalan, the brains behind the new treatment, says giving the muscles a work-out while being able to watch the actions carried out may be key to the therapy. Catalan says it could also be used as a rehabilitation aid for people who have had a stroke or those with spinal cord injuries. As he put it:

The motor areas in the brain needed for movement of the amputated arm are reactivated, and the patient obtains visual feedback that tricks the brain into believing there is an arm executing such motor commands. He experiences himself as a whole, with the amputated arm back in place.

While he and his team points out that its research is based on the study of only one patient, the success in achieving pain relief following a series of unsuccessful treatments is a clear sign of efficacy and should lead to equally successful results in other test cases. Their research appeared in a recent issue of Frontiers in Neuroscience titled “Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient”.

Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient – See more at: http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00024/full#sthash.BRadRPRS.dpuf
Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient – See more at: http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00024/full#sthash.BRadRPRS.dpuf
Treatment of phantom limb pain (PLP) based on augmented reality and gaming controlled by myoelectric pattern recognition: a case study of a chronic PLP patient – See more at: http://journal.frontiersin.org/Journal/10.3389/fnins.2014.00024/full#sthash.BRadRPRS.dpuf

And in the meantime, be sure to check out this video of the therapy being demonstrated:


Source: gizmag.com, bbc.com, journal.frontiersin.org