Feel Again

By Eric Stroud

Prosthetics have come a long way in recent years. As technology gets better and the community becomes more recognized, creative individuals from all over the world are coming together to create new solutions for amputees and limb-different patients alike. One such innovation to make big news lately is the LUKE Arm, which not only features 10 electric motors for lifelike mobility, but also nerve actuators to bring the sensation of touch back to life for its users.

The Problem is Pain

    One of the most common phenomena experienced by amputees is called “Phantom Pain”. It is a medical condition defined by Mayo Clinic as: “ pain that feels like it’s coming from a body part that’s no longer there”. It usually occurs after a patient has recently had a limb removed, and is similar to the Phantom Limb phenomenon where amputees or those missing limbs believe they can still feel their missing appendage. Once thought to be purely psychological, researchers now know that the “phantom” pain is in fact real, originating from nerve endings and the spinal column. Phantom Pain is an affliction felt by many amputees even after receiving a prosthesis.

Sensory Solutions

    Most prosthetic solutions offer functional models that look like real limbs, some of which can even move. But almost none of them can replicate the sensation of touch like real skin can. That is, not until now. A team of researchers at the University of Utah have developed a new prosthetic called the LUKE Arm that moves like a real arm. Using a modular system and 10 electric motors, it is able to mimic natural motions of the arm like abduction and rotation and is controlled entirely by signals sent directly from the brain. It can even deliver various pressures in grip strength. But the fascinating part of the LUKE Arm is its ability to deliver the sensation of touch to the brain. Using Brain-Computer Interface technology, the arm emits electrical signals controlled by a computer directly into the nerve endings where the body ends and the prosthetic begins. Lead researcher Gregory Clark explains “Participants can feel over 100 different locations and types of sensation coming from their missing hand”. This development is a breakthrough in prosthetics. “They can also feel the location and the contraction force of their muscles — even when muscles aren’t there. That’s because we can send electrical signals up the sensory fibers from the muscles, so the brain interprets them as real” he adds.

What It Means

People who experience Phantom Pain often complain that the discomfort makes it feel like the limb is still there. Prosthetics may help alleviate the feeling of null weight where a limb is absent, but the pain remains, with this new nerve technology, however, that problem may be a thing of the past.“When the prosthetic hand starts to feel like the user’s real hand, the brain is tricked into thinking that it actually is real,” Clark explains. “Hence, the phantom limb doesn’t have a place to live in the brain anymore. So it goes away — and with it, goes the phantom pain.” This bleeding-edge science will still take some time to become mainstream, but knowing that there are researchers like Clark and his team who push the boundaries of what prosthetics can be is thrilling. We are looking forward to seeing this technology develop so that one day, everyone with a prosthesis can feel again.

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