Dennis Aabo Sørensen lost his left hand after a firework exploded during a New Year’s Eve celebration in 2004. Nine years later, he took part in a clinical study where he was fitted with a prosthetic (bionic) hand. Researchers implanted tiny electrodes into his left arm, blindfolded him, and placed an object in his prosthetic hand while music played in his headphones. Sørensen was able to tell the shape and stiffness of objects and adjust the grasping force of the prosthetic with no visual or auditory feedback.
“Suddenly you could see my left hand talking to my brain again and it was magic,” said Sørensen. “It was surreal. I grabbed the object in my hand and knew it was round. It was a baseball.”
Silvestro Micera, Director of the Translational Neural Engineering Laboratory and the Institute of Bioengineering at the Center for Neuroprosthetics at École Polytechnique Fédérale de Lausanne, who worked on the project for 15 years, said the research team achieved the sense of touch by measuring the tension in artificial tendons that control finger movement, and turning that measurement into an electrical current. For Sørensen, the sense of touch was accomplished by sending the electrical current through the electrodes attached to his upper arm.
Sørensen’s excitement was short lived due to safety restrictions in clinical trials that required researchers to remove the electrodes after 30 days. He is now wearing a battery operated prosthetic that doesn’t provide him with the sense of touch.
“The main difference is you can actually feel what you are doing (with the bionic hand). With what I have now I am constantly monitoring to make sure I don’t grasp too hard since I can’t feel what I am doing,” said Sorensen.
According to Micera, it will be years before the sensory enhanced prosthetic will be available to the public. On a positive note, Micera said the study opens the door to the future of prosthetics.
“These results show the possibilities for amputees,” said Micera. “It is possible that this could be expanded to lower limbs.”
One can only imagine how significantly these bionic prosthetics will one day improve the quality of life for amputees.
Watch a Video showing the hand in action.