- DARPA researchers demonstrate a prosthetic that might communicate sense of touch to the user
- It relies on implanting electrode arrays in the brain, but they're only stable in body for several years
(CNN)Research on prosthetic hands has come a long way, but most of it has focused on improving the way the body controls the device.
Now, it may also be possible for prosthetic hands to send signals back to the body and "tell" it information about what the bionic hand is touching, according to a new study.
Recently, researchers at the Defense Advanced Research Projects Agency, the research arm of the U.S. military, implanted an array of small electrodes into the region of the brain that controls movement in a woman who is paralyzed. The electrodes communicated electrical activity from the brain's motor cortex, via wires, to a prosthetic arm that the woman was able to move through a wide range of motions.
Then the research team asked, "Can we run the experiment in reverse? Can we do for sensation what we did for the motor system?" said Justin Sanchez, program manager of the DARPA biological technologies office, in a presentation he gave on Thursday at the Wait, What? A Future Technology Forum, which DARPA hosted in St. Louis.
To answer this question, the researchers worked with a 28-year-old man who is paralyzed. They implanted an electrode array in both his motor cortex and sensory cortex, the brain region that recognizes tactile sensations such as texture and pressure. Wires from the motor cortex array controlled the hand, as they did for the female volunteer, and sensors in the hand also conveyed information, via another set of wires, back to the array in the sensory cortex.
The researchers showed that this feedback system allowed the hand to communicate directly with the brain. In a video included in Sanchez's presentation, a researcher blindfolded the man and then gently pressed on different fingertips in the prosthetic hand. The volunteer was able to identify which fingertip was being touched with "nearly 100 % accuracy" even without seeing it, according to a DARPA press release about the research.