It’s something that until recently has only been possible in movies and science fiction, but now biomedical engineering researchers at the University of Utah may have finally cracked the code on mind-controlled prosthetics that allow their user to regain sense of touch and feel. Named after Luke Skywalker’s robotic hand from Star Wars: The Empire Strikes Back, the “LUKE Hand” is a new type of robotic prosthetic hand was first developed some 15 years ago by DEKA Research & Development Corp but has just recently received an upgraded control system that is able to interface with the nerves in a human's arm.
Keven Walgamott plucks a grape from a cluster using a prototype LUKE Arm
(PHOTO CREDIT: University of Utah Center for Neural Interfaces)
Interfacing with the nervous system allows the wearer to control the hand by thought. This connection also allows sensors in the LUKE Arm’s hand to sense touch and pressure then relay that information to the correct nerves in one’s arm creating a sense of touch and feel. These new abilities make tasks such as peeling a banana, or opening a door much easier, and somewhat more intuitive for the wearer.
"We changed the way we are sending that information to the brain so that it matches the human body. And by matching the human body, we were able to see improved benefits," biomedical engineering doctoral student Jacob George says. "We're making more biologically realistic signals."
(Video Credit: University of Utah YouTube)
This remarkable breakthrough was made possible thanks to a device invented by the University of Utah biomedical engineering Emeritus Distinguished Professor Richard A. Norman. Dubbed the “Utah Slanted Electrode Array,” the device features 100 microelectrodes that are surgically implanted into an amputees nerves at the forearm with the other end of the electrodes being connected to a small wearable computer, which is then itself connected to the LUKE Arm robotic prosthetic. When the amputee thinks about opening the prosthetic hand, the brain sends a signal to the correct nerves, which is then picked up by the electrodes which are then translated into signals that control the motors and servos in the prosthetic hand. While this is happening, sensors in the hand are feeding back data to the computer such as pressure that is translated into signals that mimic the sense of touch that the brain can understand.
"We changed the way we are sending that information to the brain so that it matches the human body. And by matching the human body, we were able to see improved benefits,” says University of Utah biomedical engineering associate professor Gregory Clark “We’re making more biologically realistic signals.”
This was not as simple as just connecting the electrodes to the nerve endings though. The team at the University of Utah had to first understand how the brain handles sensory information. In this instance, when someone touches an object, a large burst of activity happens between the brain and nervous system, but then gradually decreases. To figure this out, the research team had to carefully work out the math using recorded impulses from a primate’s brain, and then create a model of how the impulses are received by the human brain.
"Just providing sensation is a big deal, but the way you send that information is also critically important, and if you make it more biologically realistic, the brain will understand it better and the performance of this sensation will also be better," George says.
Professor Clark says that Utah Slanted Electrode Array is capable of sending more sensory signals to the brain than just touch. It’s able to mimic the sense of temperature, and even pain, but the recently published research mainly focuses on the sense of touch. Additionally, while the current research focuses on hand/arm amputees who were amputated below the elbow, the same technology could work with amputees who lost limbs above the elbow. Pending federal regulatory approval, Clark has plans for three amputees to take LUKE Arms home with them for more thorough testing in day to day life.
If you would like to learn more about the LUKE Arm, or the research being done by the University of Utah, please visit this link.