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: Overcoming Paralysis

neurobridge_ianIan Burkhart, a 23-year-old quadriplegic from Dublin, Ohio, was injured in 2010 in a diving accident, breaking his neck on a sandbar and paralyzing his body from the neck down. He was left with some use of his arms, but lost the use of his legs, hands, and fingers. Thanks to a new device known as the Neurobridge though – a device that allows the brains signals to bypass the severed spinal cord – Burkhart has now moved his right hand and fingers for the first time since the accident.

This device, which was developed in concert by the Ohio State University Wexner Medical Center and the non-profit company Battelle, consists of a pea-sized chip that contains an an array of 96 electrodes, allows researchers to look at detailed signals and neural activity emanating from the patient’s brain. This chip was implanted in Ian’s brain two months ago, when neurosurgeon Dr Ali Rezai of Ohio State University performed the surgery that would implant the sensor chip into the motor cortex of his brain.

neuromorphic_revolutionBattelle has been working on neurosensing technology for almost a decade. As Chad Bouton, the leader of the Neurobridge project at Battelle, explains:

We were having such success in decoding brain activity, we thought, ‘Let’s see if we could remap the signals, go around something like a spinal cord injury and then translate the signals into something that the muscles could understand and help someone paralyzed regain control of their limb’.

During the test, which occurred in June, the implanted chip read and interpreted the electrical activity in Burkhart’s brain and sent it to a computer. The computer then recoded the signal, and sent it to a high-definition electrode stimulation sleeve Burkhart wore on his right arm, a process that took less than a tenth of a second and allowed Burkhart to move his paralysed fingers. Basically, Burkhart is able to move his hand by simply thinking about moving his hand, and the machine does the rest.

neurobridge1A team led by Chad Bouton at Battelle spent nearly a decade developing the algorithms, software and sleeve. Then, just two years ago, Dr Ali Rezai and Dr Jerry Mysiw were brought on board to design the clinical trials. Burkhart became involved with the study after his doctor mentioned it to him and he learned he was an ideal candidate. He had the exact level of injury the researchers were looking for, is young and otherwise healthy, and lives close to the Ohio State University Wexner Medical Center, where the research is being conducted.

Even so, Burkhart had to think hard before agreeing to the surgery. He also knew that the surgery wouldn’t magically give him movement again. He would have to undergo rigorous training to regain even basic hand function. Mainly, his experience would help move along future technological advances. However, he was excited to be taking part in cutting-edge research which would ultimately help people like him who have suffered from spinal injuries and paralysis.

enhancementPost-surgery, Burkhart still had a lot of thinking to do, this time, in order to move his hand. As he explained:

It’s definitely great for me to be as young as I am when I was injured because the advancements in science and technology are growing rapidly and they’re only going to continue to increase… Mainly, it was just the fact that I would have to have brain surgery for something that wasn’t needed… Anyone able bodied doesn’t think about moving their hand, it just happens. I had to do lots of training and coaching.

The hand can make innumerable complex movements with the wrist, the fingers, and the fist. In order for Battelle’s software to read Ian’s mind, it has to look for subtle changes in the signals coming from Ian’s brain. As Bouton explains it, the process is like walking into a crowded room with hundreds of people trying to talk to each other, and you’re trying to isolate one particular conversation in a language that you don’t understand.

neurobridgeAt this point, Burkhart can perform a handful of movement patterns, including moving his hand up and down, opening and closing it, rotating it, and drumming on a table with his fingers. All of this can only be done while he’s in the hospital, hooked up to the researchers’ equipment. But the ultimate goal is to create a device and a software package that he can take with him, giving him the ability to bypass his injury and have full ambulatory ability during everyday activities.

This isn’t the only research looking into bringing movement back to the paralyzed. In the past, paralyzed patients have been given brain-computer interfaces, but they have only been able to control artificial limbs – i.e. Zak Water’s mind-controlled leg or the BrainGate’s device that allow stroke victims to eat and drink using a mind-controlled robotic arm. Participants in an epidural stimulator implant study have also been able to regain some movement in their limbs, but this technology works best on patients with incomplete spinal cord injuries.

braingate_drinkassistBurkhart is confident that he can regain even more movement back from his hand, and the researchers are approved to try the technology out on four more patients. Ultimately, the system will only be workable commercially with a wireless neural implant, or an EEG headset – like the Emotiv, Insight or Neurosky headsets. The technology is also being considered for stroke rehabilitation as well, another area where EEG and mind-control technology are being considered as a mean to recovery.

From restoring ambulatory ability through mind-controlled limbs and neurosensing devices to rehabilitating stroke victims with mind-reading software, the future is fast shaping up to be a place where no injuries are permanent and physical disabilities and neurological impairments are a thing of the past. I think I can safely speak for everyone when I say that watching these technologies emerge makes it an exciting time to be alive!

And be sure to check out this video from the OSUW Medical Center that shows Ian Burkhart and the Batelle team testing the Neurobridge:


Sources: cnet.com, fastcoexist.com

The Future of Medicine: Tiny Bladder and Flashlight Sensors

heart_patchesThere’s seems to be no shortage of medical breakthroughs these days! Whether it’s bionic limbs, 3-D printed prosthetic devices, bioprinting, new vaccines and medicines, nanoparticles, or embedded microsensors, researchers and medical scientists are bringing innovation and technological advancement together to create new possibilities. And in recent months, two breakthrough in particular have bbecome the focus of attention, offering the possibility of smarter surgery and health monitoring.

First up, there’s the tiny bladder sensor that is being developed by the Norwegian research group SINTEF. When it comes to patients suffering from paralysis, the fact that they cannot feel when their bladders are full, para and quadriplegics often suffer from pressure build-up that can cause damage to the bladder and kidneys. This sensor would offer a less invasive means of monitoring their condition, to see if surgery is required or if medication will suffice.

pressuresensorPresently, doctors insert a catheter into the patient’s urethra and fill their bladder with saline solution, a process which is not only uncomfortable but is claimed to provide an inaccurate picture of what’s going on. By contrast, this sensor can be injected directly into the patients directly through the skin, and could conceivably stay in place for months or even years, providing readings without any discomfort, and without requiring the bladder to be filled mechanically.

Patients would also able to move around normally, plus the risk of infection would reportedly be reduced. Currently readings are transmitted from the prototypes via a thin wire that extents from the senor out through the skin, although it is hoped that subsequent versions could transmit wirelessly – most likely to the patient’s smartphone. And given that SINTEF’s resume includes making sensors for the CERN particle collider, you can be confident these sensors will work!

senor_cern_600Next month, a clinical trial involving three spinal injury patients is scheduled to begin at Norway’s Sunnaas Hospital. Down the road, the group plans to conduct trials involving 20 to 30 test subjects. Although they’re currently about to be tested in the bladder, the sensors could conceivably be used to measure pressure almost anywhere in the body. Conceivably, sensors that monitor blood pressure and warn of aneurisms or stroke could be developed.

Equally impressive is the tiny, doughnut-shaped sensor being developed by Prof. F. Levent Degertekin and his research group at the George W. Woodruff School of Mechanical Engineering at Georgia Tech. Designed to assist doctors as they perform surgery on the heart or blood vessels, this device could provide some much needed (ahem) illumination. Currently, doctors and scientists rely on images provided by cross-sectional ultrasounds, which are limited in terms of the information they provide.

tiny_flashlightAs Degertekin explains:

If you’re a doctor, you want to see what is going on inside the arteries and inside the heart, but most of the devices being used for this today provide only cross-sectional images. If you have an artery that is totally blocked, for example, you need a system that tells you what’s in front of you. You need to see the front, back, and sidewalls altogether.

That’s where their new chip comes into play. Described as a “flashlight” for looking inside the human body, it’s basically a tiny doughnut-shaped sensor measuring 1.5 millimeters (less than a tenth of an inch) across, with the hole set up to take a wire that would guide it through cardiac catheterization procedures. In that tiny space, the researchers were able to cram 56 ultrasound transmitting elements and 48 receiving elements.

georgia-tech-flashlight-vessels-arteries-designboom03So that the mini monitor doesn’t boil patients’ blood by generating too much heat, it’s designed to shut its sensors down when they’re not in use. In a statement released from the university, Degertekin explained how the sensor will help doctors to better perform life-saving operations:

Our device will allow doctors to see the whole volume that is in front of them within a blood vessel. This will give cardiologists the equivalent of a flashlight so they can see blockages ahead of them in occluded arteries. It has the potential for reducing the amount of surgery that must be done to clear these vessels.

Next up are the usual animal studies and clinical trials, which Degertekin hopes will be conducted by licensing the technology to a medical diagnostic firm. The researchers are also going to see if they can make their device even smaller- small enough to fit on a 400-micron-diameter guide wire, which is roughly four times the diameter of a human hair. At that size, this sensor will be able to provide detailed, on-the-spot information about any part of the body, and go wherever doctors can guide it.

Such is the nature of the new age of medicine: smaller, smarter, and less invasive, providing better information to both save lives and improve quality of life. Now if we can just find a cure for the common cold, we’d be in business!

Sources: gizmag.com, news.cnet.com

Biomedical Breakthroughs: Bionerves and Restored Sensation

restoring_mobilityThese days, advances in prosthetic devices, bionic limbs and exoskeletons continue to advance and amaze. Not only are doctors and medical researchers able to restore mobility and sensation to patients suffering from missing limbs, they are now crossing a threshold where they are able to restore these abilities and faculties to patients suffering from partial or total paralysis.

This should come as no surprise, seeing as how the latest biomedical advances – which involve controlling robotic limbs with brain-computer interfacing – offer a very obvious solution for paralyzed individuals. In their case, no robotic limbs or bionic attachments are necessary to restore ambulatory motion since these were not lost. Instead, what is needed is to restore motor control to compensate for the severed nerves.

braingate1Thanks to researchers working at Case Western University in Ohio, a way forward is being proposed. Here, a biomedical team is gearing up to combine the Braingate cortical chip, developed at Brown University, with their own Functional Electric Stimulation (FES) platform. Through this combination, they hope to remove robots from the equation entirely and go right to the source.

It has long been known that electrical stimulation can directly control muscles, but attempts to do this in the past artificially has often been inaccurate (and therefore painful and potentially damaging) to the patient. Stimulating the nerves directly using precisely positioned arrays is a much better approach, something that another team at Case Western recently demonstrated thought their “nerve cuff electrode”.

cuff-electrodeThis electrode is a direct stimulation device that is small enough to be placed around small segments of nerve. The Western team used the cuff to provide an interface for sending data from sensors in the hand back to the brain using sensory nerves in the arm. With FES, the same kind of cuff electrode can also be used to stimulate nerves going the other direction, in other words, to the muscles.

The difficulty in such a scheme, is that even if the motor nerves can be physically separated from the sensory nerves and traced to specific muscles, the exact stimulation sequences needed to make a proper movement are hard to find. To achieve this, another group at Case Western has developed a detailed simulation of how different muscles work together to control the arm and hand.

braingate2-img_assist_custom-500x288Their model consists of 138 muscle elements distributed over 29 muscles, which act on 11 joints. The operational procedure is for the patient to watch the image of the virtual arm while they naturally generate neural commands that the BrainGate chip picks up to move the arm. In practice, this means trying to make the virtual arm touch a red spot to make it turn green.

Currently in clinical trials, the Braingate2 chip is being developed with the hope of not only stimulating muscles, but generating the same kinds of feedback and interaction that real muscle movement creates. The eventual plan is that the patient and the control algorithm will learn together in tandem so that a training screen will not be needed at all and a patient will be able to move on their own without calibrating the device.

bionic-handBut at the same time, biotech enhancements that are restoring sensation to amputee victims are also improving apace. Consider the bionic hand developed by Silvestro Micerna of the École Polytechnique Fédérale de Lausanne in Switzerland. Unlike previous bionic hands, which rely on electrodes to receive nerve signals to control the hand’s movement, his device sends electronic signals back to simulate the feeling of touch.

Back in February of 2013, Micerna and his research team began testing their bionic hand, and began clinical trials on a volunteer just last month. Their volunteer, a man named Dennis Aabo Sørensen from Denmark, lost his arm in a car accident nine years ago, and has since become the first amputee to experience artificially-induced sensation in real-time.

prosthetic_originalIn a laboratory setting wearing a blindfold and earplugs, Sørensen was able to detect how strongly he was grasping, as well as the shape and consistency of different objects he picked up with his prosthetic. Afterwards, Sørensen described the experience to reporters, saying:

The sensory feedback was incredible. I could feel things that I hadn’t been able to feel in over nine years. When I held an object, I could feel if it was soft or hard, round or square.

The next step will involve miniaturizing the sensory feedback electronics for a portable prosthetic, as well as fine-tuning the sensory technology for better touch resolution and increased awareness about the movement of fingers. They will also need to assess how long the electrodes can remain implanted and functional in the patient’s nervous system, though Micerna’s team is confident that they would last for many years.

bionic-hand-trialMicerna and his team were also quick to point out that Sørensen’s psychological strength was a major asset in the clinical trial. Not only has he been forced to adapt to the loss of his arm nine years ago, he was also extremely willing to face the challenge of having experienced touch again, but for only a short period of time. But as he himself put it:

I was more than happy to volunteer for the clinical trial, not only for myself, but to help other amputees as well… There are two ways you can view this. You can sit in the corner and feel sorry for yourself. Or, you can get up and feel grateful for what you have.

The study was published in the February 5, 2014 edition of Science Translational Medicine, and represents a collaboration called Lifehand 2 between several European universities and hospitals. And although a commercially-available sensory-enhanced prosthetic may still be years away, the study provides the first step towards a fully-realizable bionic hand.

braingate_drinkassistYes, between implantable electronics that can read out brainwaves and nerve impulses, computers programs that are capable of making sense of it all, and robotic limbs that are integrated to these machines and our bodies, the future is looking very interesting indeed. In addition to restoring ambulatory motion and sensation, we could be looking at an age where there is no such thing as “permanent injury”.

And in the meantime, be sure to check out this video of Sørensen’s clinical trial with the EPFL’s bionic hand:


Sources:
extremetech.com, actu.epfl.ch, neurotechnology.com

The Future is Here: BCI Stroke Rehabilitation

stroketherapybciIn recent years, rehabilitative systems have been developed that can allow stroke victims to move animated images of their paralyzed limbs, or to activate robotic devices that guide their limbs through the desired movements. Slowly, we are entering an age where machines can turn thoughts into ambulatory ability, allowing people who suffer from paralysis to lead more fuller lives.

But scientists at the University of Wisconsin-Madison have taken it a step further with a device that acts as an intermediary between the brain and a non-responsive hand, receiving signals from the one and transmitting them to the other. Known as the Closed-Loop Neural Activity-Triggered Stroke Rehabilitation Device, it consists of two established technologies.

brain-computer-interfaceThe first of those is a brain control interface (BCI), which interprets electrical signals from the brain and uses them to control an external device. In the past, this has been used to control robotic limbs, usually to assist people dealing with paralysis. But in this case, it activates a functional electrical stimulation (FES) system that’s attached to the paralyzed hand.

Basically, when a patient thinks of tapping their fingers, the BCI reads and recognizes those signals. The computer then passes these signals along to the FES, and it causes the hand to move as desired. The idea is that by repeatedly moving their hand in this fashion, patients will rebuild the neural pathways that previously allowed them to do so unaided.

stroketherapybci-1To test the device, Dr. Vivek Prabhakaran and Dr. Justin Williams, brought together eight stroke patients – all of whom had lost at least partial use of one hand. Over the course of 9 to 15 sessions over a period of three to six weeks, each session lasting from two to three hours, they conducted clinical trials with their machine and recorded the results.

This was conducted using a functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) device. By scanning the patient’s brains before, during and after the trials, they were able to determine that the sessions resulted in a reorganization of the parts of the brain involved in motor function, while the DTI showed a strengthening of fibers in the white matter area of the brain.

brain-computer-interface1Although there was some variation depending on the severity of each person’s stroke, the overall effect ws that patients experienced an improvement in motor function, and reported an improvement in their ability to perform daily activities. Looking long-term, Dr. Vivek Prabhakaran said that:

Our hope is that this device not only shortens rehabilitation time for stroke patients, but also that it brings a higher level of recovery than is achievable with the current standard of care.

Up until recently, the idea of using electrostimulus to send signals directly from the brain to the limbs, bypassing spinal injuries or other impediments to ambulatory ability, has been considered the province of science fiction. However, ongoing research and testing has been pushing the limits of what is possible with this technology.

Using our minds to control machinery is certainly an impressive feat, but using our minds to control machinery to restore or expand our abilities to control our own bodies. Not only is that impressive, its potentially revolutionary, and portends of an age where there is no such thing as permanent injuries or loss of ability anymore.

Sources: gizmodo.com, rsna.org