Losing a limb or an appendage through injury or illness is undoubtedly one of the most traumatic non-fatal experiences that anyone can go through. Despite the fact that modern prosthetics often mean amputees are now able to manage most things their fully able-bodied peers can, there are still limits. One of the most obvious of those is the loss of the sense of touch. But the latest technology in the world of robot prosthetics means that is about to change.
This week the Science Robotics journal published details of a research project that has developed what has been dubbed the “Luke Arm”. The new prosthetic technology is named in reference to the robotic hand Luke Skywalker is fitted with in the film The Empire Strikes Back. The technology, that allows the wearer to control a robot arm and hand prosthetic by thought, in a way similar to how a natural biological hand is controlled, also miraculously offers a sense of touch.
The greater dexterity the latest robotics used in the hand provide is complimented by that sense of touch transmitted back to the brain of the wearer. The result is not only the joy of again having the experience of touch once provided by a lost body part but the practical ability to judge the pressure the prosthetic is applying. That means the wearer can do things such as pick up a grape or raw egg without damaging it.
The prosthetic contains a bundle of 100 microelectrodes and wires that are grafted into the forearm, connecting to the median and ulnar nerves. They are also connected to an external computer. As well as bridging the gap between these nerves and the robot hand meaning the wearer controls its movements are controlled by the same subconscious thoughts that transmit impulses from the brain to the hand, signals can also be sent in the opposite direction. That means the user can feel pressure, movement, vibrations and even pain. As explained by Dr Gregory Clark of the University of Utah, one of the lead scientists behind the research project:
“When you touch objects with a natural hand, there’s an extra burst of neural impulses when you first make contact, or when you change your grip force”.
“That’s the type of information that brain normally receives, so that’s what it finds easiest to interpret. So that’s also the type of information that we tried to send to the brain — and it worked.”
The development will give hope to millions of amputees around the world that science is now potentially only a few years away from commercially available prosthetics that get much closer to offering a technology that replicates the full functionality of biological limbs and appendages.