The original LUKE arm was named after Luke Skywalker’s robotic hand in “The Empire Strike’s Back” and designed to perform various movements.
Now, it can not only help users to perform various movements, but it also mimics the way the brain and hand send signals to each other, allowing them to essentially “feel.”
Even when people are holding things blindfolded, the nerves in their hands immediately send signals to the brain regarding how the object is to be held based on past experiences as well as the characteristics of the object itself. For instance, a person holding an egg while blindfolded will still know that it is an egg by its characteristics and that it is an object that must be held gently.
This, however, is something that prosthetic limbs cannot easily recreate. While there are existing prosthetic limbs that can convert brain signals into movement, most still require visual cues to determine how an object must be held.
The LUKE Arm
The nerves that allow people to control the hand and send messages to the brain still exist even after the hand has been amputated. By implanting 100 microelectrodes and wires in some of those nerves, a research team from the University of Utah observed how the LUKE arm was able to mimic how the brain sends signals to the hand to touch an object, and how the hand returns signals in response to the touch.
This means that users of LUKE arm can get a sense of the characteristics of the objects they are touching, understand how they should pick it up, and then perform even delicate tasks that are near impossible with other standard prosthetic arms. In fact, in clinical tests, amputee Keven Walgamott was able to pluck grapes without crushing them, carefully pick up an egg, and feel sensations in the robotic fingers when he held his wife’s hand.
“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,” said team leader Gregory Clark.
For future tests, researchers are hoping to create a wireless version of the device that can be implanted inside the body so that it can be routinely used at home. So far, the LUKE arm can only be used in the laboratory with the supervision of a researcher, and the surgically implanted wires on Walgamott's arms were removed after the 14-month study.
The findings by the multidisciplinary team are published in the journal Science Robotics.