Robotic prostheses currently used to give at least a bit of dignity to those who lost a hand or an arm due to an accident, have several limitations. First of all, along with the discomfort and trouble in wearing them, comes the lack of response under the sensory point of view, which makes it very hard to forget that the piece of plastic you are wearing is not your hand.

At the University of Michigan, researchers are working on a sort of sleeve, to be placed over nerve endings which have been severed with the accident; the sleeve can improve hand prostheses’ performance, and restore sense of touch in patients.

The researchers have created a sort of interface made up of muscle cells and polymeric material, which connects the nerve endings to the prosthetic hand. Thanks to this neuro-muscular junction, the brain can control muscles’ movements. By using the interface, signals sent by the nerve endings towards the brain, which are normally useless, can be used to control muscle movements and generate touch sensations.

Muscle cells mounted on the “glove” and nerve endings on the limb interact with each other, creating a stable connection. In laboratory tests, results are showing that not only does the usage of this interface improve the prosthetic hand’s motion control, but it mostly makes it possible to have a two-way communication, sending temperature and touch impulses to the brain, enabling it to tell a rough surface from a smooth one, or cold from hot.

The project, funded by the US Department of Defense, is initially aimed at improving the life of those who came back from Iraq or Afghanistan with permanent injuries, but it is obviously opening interesting possibilities for those who suffered mutilations while working. The first tests on humans are scheduled in approximately three years from now.