8/26/2014
SARCDev, the Society for Advances and Research in Cybernetic's development company, has announced plans to develop a new kind of neural interface. The device, the Neural Grid Relay (NGR), utilizes a series of channels in an implantable delrin wafer cube powered by 30 year tritium batteries. Today's neural interfaces all exist as wires which are placed along side or injected through a nerve fiber. The NGR is capable of both sensing signals and inducing signals into each nerve. "Conveying the sense of touch back to the user is key and a major advance over today's available prosthetics" says SARC founder Gianna Giavelli. The advantage is that it can be implanted further back in the limb where nerves join together into a bundle. Each NGR device is capable of controlling forty nerve fibers with plans to increase that to over a hundred.
Todays cybernetic hand efforts, currently happening mostly via the University of Rome's BioHand project, use implantable wires which exit through the skin. As we found out in America, once wires decay they leave behind a mess which is impossible to remove, as was the case with early experiments with wire controlled muscles for locomotion in paralyzed patients. And since they exit the skin, there is a huge chance of infection. The NGR solves this problem by being fully implantable. The surgical technology to dissect the nerve bundle without damage and overlay nerves into the grooves is still being developed but looks promising.
The NGR provides another unique trait, it has a built in RF receiver and transmitter. "We looked at making it fully bluetooth compatible but eventually settled on a simpler stream interface for our first prototype" said Giavelli. "The advantage of the embedded RF circuit is that now we can program it with a transmitter we place over the NGR. We use this to re-code the connections of what nerve goes to what finger or part of the hand. And similar recoding is used to send back sensation to the right place. The first time someone senses something with the NGR, we may be touching their pinky finger but they might say they feel it on their wrist. So we simply re-map that input to their wrist. It allows a lot of flexibility"
Doing away with the external wires was key. In fact the Italian device has a limit of only being allowed for 30 days in test patients due to infection risk and wire degradation risk. "Metal rusts in the body!" says Giavelli. "It's a terrible choice for neural interfacing. Instead we implant tiny amounts of metal within the NGR alongside the channels. One set for stimulation, one set for sensing. They never come into contact with fluid. The difficult part is the clam shell lid which must keep out most of the bodies moisture without compressing the nerve. We've found that actually we can get enough pressure to accomplish both challenges."
The RF provides another benefit, it signals from within the body to the prosthesis, in this case a hand. "We envision a model where the hand is charged overnight, and then put on in the morning. Once connected, the RF system is established and the user feels like it is just like their own hand."
When asked what is the difference between cybernetic research and typical approaches Giavelli responded "If you look at the hand they are using in Italy, and while clearly its just a prototype, it looks like something freddy kruger would wear. Cybernetics take from the onset modeling fully the way the human system is designed, with real bone and ligament structures. So not only does it look lifelike down to the fingernails and hairs, which is a huge win for patients, it actually has similar functionality levels. One example of this is complex hand movements when you move your pinky towards your thumb. Many bones within the hand flex and rotate. Similarly when you pull four of your fingers back, there is another slight rotation within the hand. If you build the entire hand beneath the fingers as one solid piece of metal, of course you can never replicate the human's ability for delicate and complex grasping. But with cybernetic approaches, although more difficult to develope, our target is a perfect mimic of the system that has already been perfect through evolution. It's the same with brain cybernetics, we seek to achieve systems that mirror not re-think what has taken millions of years to evolve."
Since the protocols for doing this kind of development work is so strict in the United states, most of the research is being conducted outside of America. "Our plan is to work in Africa, where so many have suffered loss of limbs in the terrible fighting, but then be able to apply our success to American GIs who were wounded in Iraq."
When asked what the future holds, Giavelli responded "Well the potential of this multi-channel RF bridge is enormous in more complex systems like spinal injury, but we are at the beginning stages. It will take several orders of magnitude of advancement before we could bridge the number of nerves in spinal columns. Still there are some applications which are not so obvious. In Multiple Sclerosis patients, where the nerves myelin sheathing is damaged and can't propagate a nerves signal very far, we might be able to build boosters using the same technology, in much the same way that you can buy a WiFi booster to increase the signal of your home wireless network."
For more information, SARC Development can be reached at SarcDevelopment @ gmail.com
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