When you think Star Wars, your mind will probably drift to space battles and quasi-religious hermits. However, when researchers at the Defense Advanced Research Projects Agency (DARPA) reflected on the films, their thoughts apparently focused on Luke Skywalker’s robotic hand.
DARPA is a branch of the U.S. Department of Defense whose aim is to develop new technologies for the U.S. military. Known mostly from their Grand Challenge competition in which teams of engineers build autonomous vehicles that are designed to navigate a treacherous course. DARPA has also been developing next generation prosthetics.
DARPA has funded two projects with its Revolutionizing Prosthetics program, one of which involves the development of an advanced neural-interfaced prosthetic arm, and the other is to develop a prosthesis using current technology for immediate use.
Dean Kamen, an inventor and owner of the Deka Corporation, received funding from DARPA in 2005 to develop his so-called “Luke Arm,” an intelligent prosthetic device that would give amputees incredible amounts of freedom without requiring surgical intervention. According to Dean, current prosthetics are uncomfortable and cumbersome, and “usually within a year or two, patients stop wearing their prostheses.”
The new prosthetic will allow for never-before-seen amounts of freedom, which it achieves with non-invasive controls, using an “interface a bit like a joystick.” This would allow amputees to perform the tasks we take for granted — things like opening a door or shaking someone’s hand.
Since there can be no nerve interface, the team devised a clever system to provide tactile feedback to the user. A small vibrating motor, or tactor, is placed against the patient’s skin. Sarah Adee, writing for Danshope.com, explains how the system works: “When a user grips something lightly, the tactor vibrates slightly. As the user’s grip tightens, the frequency of the vibration increases.” Test results have proven positive so far, but the project is still waiting for partners who could fund FDA clinical trials.
The other part of the DARPA project, the neural interface, is being developed by the John Hopkins Applied Physics Laboratory and is currently in phase three of the program — meaning it’s ready to be tested on human subjects. Neural interfacing has proven to be possible when researchers in Pittsburgh completed a test that “showed that a pair of macaque monkeys with tiny chips implanted in their brains could operate a robotic arm just by thinking about it.”
The system works by using “hair-like electrodes to record neurological signatures in the brain,” which are then interpreted as instructions by a computer. The computer then relays these instructions to the prosthetic, thereby allowing a patient to control the robotic arm using only their thoughts. If the project is successful, there may be new hope for people with paralysis — to whom traditional prosthetics are useless.
The researchers have stated that their next goal is to “focus on closing the loop by stimulating the brain to sense pressure and touch” and they may have just gotten a whole lot closer. Synthetic skin that would allow a patient to feel has been making great strides recently, mainly due to carbon nanotubes.
The synthetic skin consists of carbon nanotubes embedded in a polymer, which according to an io9.com article “generates electricity in response to pressure or force, creating signals that can be routed to your brain.” One approach to route the messages to your brain involves redirecting the nerves from the chest muscles to the artificial skin. A Spectrum.ieee.org article reported “patients could actually sense touch, heat, cold and pain on the skin of the chest as if it were on the skin of the missing hand.” Currently, experiments are attempting to provide patients with finer nerve-redirection to allow for even more natural control.
There’s really no limit to the medical technology benefits that could come from interfacing directly with the human brain. These small steps, although coming from an unlikely source, will no doubt benefit countless amputees and the technology developed as a result will no doubt affect our lives in unimaginable ways.
