The macro-sieve created by Daniel Moran. Daniel Moran and his team are developing an electrode implant to re-create sense of touch for amputees. (via Daniel Moran)
There have been several innovations in modern prosthetics from ones controlled with the power of your mind to ones created by 3D Printers, but they still lack the sense of touch for amputees. Daniel Moran, professor of biomedical engineering, and his team at Washington University in St. Louis are hoping to change that.
Moran's method would use an electrode capable of connecting a prosthetic arm's robotic sense of touch to human nervous systems it may be attached to. The electrode, called a marco-sieve peripheral nerve interface, is made of a thin material, similar to a contact lens, that's 20 percent the diameter of a dime and resembles a wagon wheel with open spaces to allow the nerve to grow. It's supposed to allow users to feel heat, cold, and pressure by simulating the ulnar and median nerves of the upper arm. Moran and his team received a $1.9 billion grant from Defense Advanced Research Projects Agency (DARPA) for testing.
Figure A shows nerve regeneration through the high-transparency regenerative macro-sieve electrode. Figure B shows a regenerated nerve through a silicone conduit. Figures C and D are epoxy nerve sections demonstrating numerous myelinated axons. (Credit: Dan Moran, PhD, Washington University in St. Louis)
While it sounds good on paper, the now three year old project has a while to go. Before the device can be implanted in to people, Moran's team needs to determine how much sensory information is actually encoded in natural systems. For testing, prototypes will be implanted into the forearms of “nonhuman primates,” which will then be monitored for the stimulation of peripheral nerves using the current steering technique. Current steering uses multiple stimulation sources to direct current flow through specific regions of brain tissue. The test subjects will then be taught, by Moran and his team, to play a video game using a joystick. The team will give them cues as to how to move the joystick by stimulating ulnar and median nerves.
In a statement about further development, Moran said “We want to see what they can perceive. If we stimulate this sector of the nerve, that tells them to reach to one side in a standard reaching task. We want to figure out how small we can make the stimulation so they can still sense it.” Once the team has the appropriate information, they'll be able to create more accurate sensor suites in future prosthetics, similar to the Luke Hand that DARPA is currently building. The Luke Hand is a high tech bionic limb created by DEKA Research designed to help servicemen, women, and veteran with upper arm amputations.
This is a big step forward in modern prosthetics. If all goes well, Moran's device will allow amputees to feel certain objects, such as hot mugs, which gives them more control over the prosthesis. They will no longer have to rely solely on their vision to determine how to use objects more efficiently.
C
See more news at: