Fabrizio Fidati tests a temperature-sensitive prosthetic arm.

EPFL Calet

A man whose right arm was amputated below the elbow has been able to sense heat and cold in his missing hand using a prosthetic arm modified with thermal sensors.

After amputation, some people may still feel a sense of touch and pain in their missing arm or leg, known as a phantom limb. Sometimes, these sensations may originate from nerve endings in the residual upper limb.

The prosthesis works by applying heat or cold to the skin of the upper arm at specific locations, which creates a thermal sensation in the phantom’s hand.

“In previous research, we’ve shown the presence of these spots in the majority of patients we’ve treated,” he says. Solomon Shakur at the Swiss Federal Institute of Technology in Lausanne.

First, Shukur and his colleagues mapped spots on study participant Fabrizio Fadati’s upper arm that generated sensations in different parts of his phantom hand. Then they adapted his existing prosthetic hand and socket with sensors and devices that can be heated or cooled, called thermods.

Tests show that Fidati can identify hot, cold or ambient temperature bottles with 100 percent accuracy by touching them with his modified prosthetics. When the thermal sensor was turned off in the synthetic, its accuracy dropped to one-third.

The prosthesis also allowed Fadati to successfully distinguish, while blindfolded, glass, copper and plastic from touch with just over two-thirds of the accuracy – just like his uninjured left hand. It’s like

In a separate study published recently, Shukur and his colleagues showed that amputees using a temperature-sensitive prosthesis It can detect whether objects are wet or dry.

“We could give the amputated babies a sense of humidity and … they were just as good at detecting different levels of humidity as they were with their hands,” Shukur says.

Omid Kavihi The University of Sydney, Australia, says the research could one day have applications beyond artificial objects, such as giving robots a greater range of physical sensations.

“This is extraordinarily important work,” he says. However, he cautions that this was not a clinical trial and wonders how well the technology will work in the real world, where hot and cold weather abounds.

“I would like to see how the device performs in a hot and humid place like Singapore,” says Kavihi.