Surgeons implanted two ultra-thin electrodes each directly into the ulnar and median nerves in the upper arm of Dennis Sørensen. The electrodes send sensory data by means of electrical impulses from the patient’s artificial hand directly to his brain over the peripheral nervous system. They give him information about the shape and consistency of the objects he grasps at, even when he cannot see them.
To test out the arm
, Sørensen managed to sense objects like a plastic cup, a mandarin orange, and a heavy block of wood while being blindfolded and to take hold of them with a precise grip and the right amount of force.
Some of this is shown in the video below:
Talking to The Australian
, Sørensen said: “When I held an object, I could feel if it was soft or hard, round or square. I could feel things that I hadn't been able to feel in over nine years.”
As the development has yet to be approved by European regulators, the electrodes had to be removed after 30 days. It is hoped that once approval has been given,, Sørensen can have the bionic arm fitted permanently.
The development was carried out by Freiburg microsystems
engineer Prof. Dr. Thomas Stieglitz and the international research group participating in the project LifeHand2. The development has been outlined in
the publication Science Transitional Medicine
, in a paper titled “Restoring Natural Sensory Feedback in Real-Time Bidirectional Hand Prostheses.”