Scientists have moved closer to enabling amputees with artificial limbs to feel what they are touching. The first bionic hand that will allow the wearer to experience touch again will enter trials later this year, thanks to the work of scientists at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland and their partners at Project TIME (Transverse Intrafaciscular Multichannel Electrode System) — a program focused on the treatment of phantom limb pain.
Silvestro Micera, one of the lead scientists at the EPFL, made the announcement at the 2013 Annual Meeting of the American Association for the Advancement of Science (AAAS) in Boston earlier this month. The new prosthetic is based on an interface tested in 2009 on an amputee, 26-year old Pierpaolo Petruzziello. Intraneural electrodes – small pieces of polymer wiring that can deliver electrical impulses directly to the nerve – were implanted into Petruzziello’s median and ulnar nerves. By analyzing his motor neural signals, researchers found that the information specific to grasping could be isolated among these signals from the nerves, and by feeding these back to the prosthetic hand, it was possible to flex and control it.
Up to 50% of hand amputees don’t use their prosthesis regularly because of lack of functionality, appearance and controllability, according to some studies. This breakthrough could change that, making it possible for amputees to have a bidirectional flow of information between their nervous system and the prosthetic hand. “We could be on the cusp of providing new and more effective clinical solutions to amputees in the next two years,” Micera said in a statement.
Micera and his colleagues are hoping to improve the interface, especially in the areas of sensory feedback and overall control of the prosthetic. Speaking with the Independent, Micera said that another bionic hand will be transplanted later this year onto an unnamed man in his 20s in Rome, who lost the lower part of his arm as a result of an accident.
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Unlike the earlier tests, the new patient will be given a prosthesis that sends sensory signals back from each of the fingertips, in addition to the palm and wrists. “The idea would be that it could deliver two or more sensations. You could have a pinch and receive information from three fingers, or feel movement in the hand and wrist,” said Micera.
Also at the AAAS, neurobiologists at Duke University in North Carolina announced details of research using brain implants in rats that allowed them to “touch” invisible infrared light. Miguel Nicolelis, who led the research, explained that this new sixth-sense could be used to control prosthetic devices by thought alone. Said Nicolelis at the meeting, “We could learn to detect other sorts of signals that we normally don’t see or experience.”