For years scientists have been developing artificial arms that can feel objects and differentiate between different shapes just like normal arms can but without much success. The endeavor seem to be bearing fruit as for the first time researchers in Europe have been able to develop a prosthetic arm that can respond closely to touch as a normal arm does. National Post writes that for the first time a prosthetic arm can “not only…tell differences in the shape and hardness of objects, [but also] quickly react and adjust…grasp.”
To test the practicability of the arm, a team of European Engineers provided Denis Aabo Sørensen, a middle aged man who lost his arm nine years ago, with robotic arm for one month. The robotic arm was fitted with sensory connectors that connect directly to arm’s nerve endings and able to send sensations of touch back through his arm and into his brain.
“While Sørensen had it on, however, he demonstrated for researchers that he was able to do things like distinguish between a bottle, a baseball and a mandarin orange, and press things with light, medium or firm pressure. He wore a blindfold and headphones while completing each of these tasks, to prove he could do them only by touch”, reports Popular Science.
“It was just amazing… and the closest I have had to feeling like a normal hand,” said Dennis as he demonstrated to the researchers how easily he can use the artificial arm.
For years those on prosthetic arms tend not to use their artificial arms as they would like to. This is because the process of using the arm requires a lot of visual attention in order to grab objects and move them around. For example, since they normally cannot feel the objects they hold, one can easily break utensils by either grabbing them loosely or too tight.
The process of making the artificial arms convey feeling of touch has been challenging for researchers. The challenges seem to have been overcome given the positive feedback from Dennis. In Dennis’ case, doctors first implanted tiny electrodes inside two nerves in the stump of Sorensen’s arm. The tiny electrodes in the two nerves (the ulnar and median nerves that normally allow for certain sensation in the hand) were then connected to sensors in the prosthetic which detect touch by the artificial arm.
Information about touch from the artificial fingers was conveyed via wires to the electrodes in the ulnar and median nerves which in tern conveyed the pulses to the brain – the brain interpreting them as touch.
“It is really putting the brain back in control of the system,” said biomedical engineer Dustin Tyler of Case Western Reserve University, who wasn’t involved with the European work but leads a team in Ohio that recently created and tested a similar touch-enabled hand, reports National Post.
The research that scientists want to expand to paralyzed patients is still in infancy. After refining the sense of touch scientists are set to work on other touch senses such as texture and temperature.