Katharina Buczek
This phenomenon of experiencing phantom thermal sensations varies among amputees, indicating that the nerves severed during amputation are still present in different areas of the arm’s skin.
Stimulating these specific skin patches with hot or cold items triggers a response along the pathways to the brain that were originally associated with the hand. Consequently, this leads the amputee to perceive those temperatures in their missing limb.
According to Roberto Renda, a participant in a trial related to the study, he was able to “feel the warmth of another person” with his phantom hand for the first time in two decades.
“It’s like having a connection with someone. I would like to feel both of my kids’ hands when I walk down the street with them, holding their hands. That would be nice,” Roberto said.
In the initial study, 17 out of 27 participants experienced these phantom thermal sensations, which played a crucial role in demonstrating the effectiveness of the MiniTouch system.
MiniTouch is a slender, wearable sensor designed to fit seamlessly over a prosthetic finger and connect to specific areas on the skin of the residual limb. These areas are identified for their ability to generate sensations that the amputee feels as though they are coming from the absent hand.
But, even though the 2023 study established that the sensor could assist amputees in sensing temperature, the latest research marks the first instance of its application on a working prosthetic.
Fabrizio Fidati, a 57-year-old amputee, volunteered to test the device with his current prosthesis. He was given three identical bottles filled with water at varying temperatures, including cold (53 degrees Fahrenheit), cool (75 degrees Fahrenheit), and hot (104 degrees Fahrenheit).
His ability to differentiate between the bottles was correct only 33% of the time without the device. However, with the MiniTouch equipped, Fabrizio’s identification accuracy soared to 100%.
Afterward, he was asked to organize identical metal cubes that were either heated or cooled to various temperatures. The use of the temperature-sensitive prosthetics significantly enhanced his ability to do this.
Interestingly, Fidati also noted that the sensations of heat and cold felt through his phantom hand were even more pronounced than those in his intact hand.
