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 is Here: Deka Mind-Controlled Arm Gets FDA Approval!

Deka_armFor years, biomedical researchers have been developing robotic prosthetics of greater and greater sophistication. From analog devices that can be quickly and cheaply manufactured by a 3-D printer, to mind-controlled prosthetics that move, to ones that both move and relay sensory information, the technology is growing by leaps and bounds. And just last week, the FDA officially announced it had approved the first prosthetic arm that’s capable of performing multiple simultaneous powered movements.

The new Deka arm – codenamed Luke, after Luke Skywalker’s artificial hand – was developed by Dean Kamen, inventor of the Segway. The project began in 2006 when DARPA funded multiple research initiatives in an attempt to create a better class of prosthetic device for veterans returning home from the Iraq War. Now, the FDA’s approval is a huge step for the Deka, as it means the devices are now clear for sale — provided the company can find a commercial partner willing to bring them to market.

Deka_arm1Compared to other prosthetics, the Deka Arm System is a battery-powered device that combines multiple approaches. Some of the Deka’s functions are controlled by myoelectricity, which means the device senses movement in various muscle groups via attached electrodes, then converts those muscle movements into motor control. This allows the user a more natural and intuitive method of controlling the arm rather than relying on a cross-body pulley system.

Deka_Arm2The more advanced myoelectric systems can even transmit sensation back to the user, using the same system of electrodes to simulate pressure sensation for the user. This type of control flexibility is essential to creating a device that can address the wide range of needs from various amputees, and the Deka’s degree of fine-grained control is remarkable. Not only are user’s able to perform a wide range of movements and articulations with the hand, they are able to sense what they are doing thanks to the small pads on the fingertips and palm.

Naturally, the issue of price remains, which is consequently the greatest challenge facing the wide-scale adoption of these types of devices. A simple prosthestic arm is likely to cost $3000, while a sophisticated prosthesis can run as much as $50,000. In many cases, limbs have a relatively short lifespan, with wear and tear requiring a replacement device 3 to 4 years. Hence why 3-D printed variations, which do not boast much sophistication, are considered a popular option.

bionic-handVisual presentation is also a major issue, as amputees often own multiple prostheses (including cosmetic ones) simply to avoid the embarrassment of wearing an obviously artificial limb. That’s one reason why the Deka Arm System’s design has evolved towards a much more normal-looking hand. Many amputees don’t want to wear a crude-looking mechanical device.

At present, the prosthetic market is still too broad, and the needs of amputees too specific to declare any single device as a one-size-fits-all success. But the Deka looks as though it could move the science of amputation forward and offer a significant number of veterans and amputees a device that more closely mimics natural human function than anything we’ve seen before. What’s more, combined with mind-controlled legs, bionic eyes and replacement organs, it is a major step forward in the ongoing goal of making disability a thing of the past.

And in the meantime, check out this DARPA video of the Deka Arm being tested:

 


Source: extremetech.com