Using an artificial fingertip surgically connected to nerves in the upper arm, an amputee felt smoothness and roughness textures in real time. The technology, developed by a team at Ecole polytechnique fédérale de Lausanne (EPFL), does not require surgery.
"The stimulation felt almost like what I would feel with my hand," said amputee Dennis Aabo Sørensen about the bionic prostheses. "I still feel my missing hand; it is always clenched in a fist. I felt the texture sensations at the tip of the index finger of my phantom hand."
Nerves in Sørensen's arm were wired to an artificial fingertip equipped with sensors. A machine controlled the movement of the fingertip over different pieces of plastic engraved with different patterns, smooth or rough.
As the fingertip moved across the textured plastic, the sensors generated an electrical signal. The signal was translated into a series of electrical spikes, imitating the language of the nervous system, then delivered to the nerves.
Sørensen could distinguish between rough and smooth surfaces 96% of the time.