Scientists say they have overcome one of the last hurdles to giving prosthetics the full range of sensations a human limb can feel. The team achieved this by implanting a small device into the prosthetic arm.

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To make the technology work, engineers placed a temperature sensor at the tip of the index finger. It is connected to a structure called thermodome and then to the patient’s body. This created a feedback loop in which temperature changes detected by the sensor were transmitted to the human’s central nervous system. The brain interpreted temperature changes as being “felt” in the absent hand.

Fabrizio, a 57-year-old Italian man whose last name was not disclosed for privacy reasons, lost his arm below the elbow when he was in his 20s. He was the first person to receive the new device. For more than a year, he participated in laboratory experiments that eventually demonstrated his ability to sense temperature through the prosthesis.

• For example, in one of the experiments, Fabrizio successfully distinguished visually identical bottles of water with temperatures ranging from 40 to 20 degrees Celsius. He distinguished the temperature accurately every time he used the new device; This rate was 33% when it was closed.
• In another test, it separated metal cubes of different temperatures much faster with the device than without it.
• Finally, blindfolded Fabrizio was able to distinguish a human hand from a prosthetic one by touch alone in 80% of the tests.

The researchers who developed the new device say that the invention not only serves a useful function but can also make the lives of people with amputations more enjoyable.

What was really cool to see was that one day Fabrizio accidentally touched the hand of one of the students. [у лабораторії] and he said: “Wow, that’s a man.” So the great thing is that you can feel yourself touching another person.
– tell the developers.

Over the years, technological advances have improved the ability of various prosthetics to detect touch. But temperature perception was difficult to reproduce artificially.

In 2023, Silvestro Misera, professor of translational neuroengineering at the Swiss Federal Institute of Technology in Lausanne, and his colleagues discovered that people who had part of their arm amputated could still feel temperature differences in the skin where the limb used to be. It is also well known that amputees often continue to feel them as if they were still there. So the team set out to find a way to harness this emotion.

• The big advantage of the new method is that it does not require prosthesis replacement. Sensors can be integrated into any existing sensors used by the patient.
• Additionally, there is no need for surgery for installation.
• Also, the device is powered by a battery, so it does not need to be connected to the mains, which makes it more convenient to plug it in.

The team is currently developing the device; For example, they want to see how factors such as temperature and humidity can affect the performance of the device. They hope to soon develop a prosthesis that will restore all the sensations experienced by the human hand and can be used at home.