Researchers have developed a device that allows amputees to distinguish by contact between objects of different temperatures, using phantom sensing. The new technology was tested on 57-year-old Fabrizio Fidetti, whose arm was amputated below the elbow 37 years ago.
In the area of the stump there are points where nerves pass that were used in the past to sense heat in the hand. In a previous study, the researchers discovered that heating or cooling such points may activate these nerves in some subjects, allowing the brain to sense the temperature in the fingers of the amputated hand, despite its lack. The researchers called this reaction "phantom thermal sensation", that is, a simulated sensation of heat coming from an organ that does not exist. They hoped, therefore, to create a local change of temperature in sensitive points, to allow the subject to feel the temperature of the objects touched by the prosthetic hand. This way they could instruct the brain feel, as if the sensation came from the lost biological hand.