Tag: disability

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

The Future is Here: “Terminator-style” Liquid Metal Treatment

t1000_1For ideal physical rehab, it might be necessary to go a little “cyborg”. That’s the reasoning a Chinese biomedical firm used to develop a new method of repairing damaged nerve endings. Borrowing a page from Terminator 2, their new treatment calls for the use of liquid metal to transmit nerve signals across the gap created in severed nerves. The work, they say, raises the prospect of new treatment methods for nerve damage and injuries.

Granted, it’s not quite on par with the liquid-metal-skinned cyborgs from the future, but it is a futuristic way of improving on current methods of nerve rehab that could prevent long-term disabilities. When peripheral nerves are severed, the loss of function leads to atrophy of the effected muscles, a dramatic change in quality of life and, in many cases, a shorter life expectancy. Despite decades of research, nobody has come up with an effective way to reconnect them yet.

nerveVarious techniques exist to sew the ends back together or to graft nerves into the gap that is created between severed ends. And the success of these techniques depends on the ability of the nerve ends to grow back and knit together. But given that nerves grow at the rate of one mm per day, it can take a significant amount of time (sometimes years) to reconnect. And during this time, the muscles can degrade beyond repair and lead to long-term disability.

As a result, neurosurgeons have long hoped for a way to keep muscles active while the nerves regrow. One possibility is to electrically connect the severed ends so that the signals from the brain can still get through; but up until now, an effective means of making this happen has remained elusive. For some time, biomedical engineers have been eyeing the liquid metal alloy gallium-indium-selenium for some time as a possible solution – a material that is liquid at body temperature and thought to be entirely benign.

Liquid metal nervesBut now, a biomedical research team led by Jing Liu of Tsinghua University in Beijing claims they’ve reconnected severed nerves using liquid metal for the first time. They claim that the metal’s electrical properties could help preserve the function of nerves while they regenerate. Using sciatic nerves connected to a calf muscle, which were taken from bullfrogs, they’ve managed to carry out a series of experiments that prove that the technique is viable.

Using these bullfrog nerves, they applied a pulse to one end and measured the signal that reached the calf muscle, which contracted with each pulse. They then cut the sciatic nerve and placed each of the severed ends in a capillary filled either with liquid metal or with Ringer’s solution – a solution of several salts designed to mimic the properties of body fluids. They then re-applied the pulses and measured how they propagated across the gap.

liquid metal nerves_1The results are interesting, and Jing’s team claim that the pulses that passed through the Ringer’s solution tended to degrade severely. By contrast, the pulses passed easily through the liquid metal. As they put it in their research report:

The measured electroneurographic signal from the transected bullfrog’s sciatic nerve reconnected by the liquid metal after the electrical stimulation was close to that from the intact sciatic nerve.

What’s more, since liquid metal clearly shows up in x-rays, it can be easily removed from the body when it is no longer needed using a microsyringe. All of this has allowed Jing and colleagues to speculate about the possibility of future treatments. Their goal is to make special conduits for reconnecting severed nerves that contain liquid metal to preserve electrical conduction and therefore muscle function, but also containing growth factor to promote nerve regeneration.

future_medicineNaturally, there are still many challenges and unresolved questions which must be resolved before this can become a viable treatment option. For example, how much of the muscle function can be preserved? Can the liquid metal somehow interfere with or prevent regeneration? And how safe is liquid metal inside the body – especially if it leaks? These are questions that Jing and others will hope to answer in the near future, starting with animal models and possibly later with humans..

Sources: technologyreview.com, arxiv.org, cnet.com, spectrum.ieee.org