Our ability to throw a ball, walk down a sidewalk, or talk without mumbling is in part because of proprioception, the ability for us to intuitively know where our feet are, how our hands our moving, and what the mouth is doing. Without proprioception, we’d have to look down at our feet on every step to make sure everything is going well. Users of prosthetic devices face this issue every day, but researchers at École polytechnique fédérale de Lausanne in Switzerland, EPFL, the Sant’Anna School of Advanced Studies in Pisa and the A. Gemelli University Polyclinic in Rome, have now come up with a way to give prostheses the ability to relay their position to the user, as well as provide the important sense of touch.
Amputees outfitted with a new prosthetic arm are able to identify the shape, size, and other basic features of objects they’re only allowed to touch with the device. The device works by electrically stimulating nerves left over in the patient’s stump, which carry information to the brain and recreate the necessary sensations. This is done using implanted electrodes that are able to carefully stimulate the target nerves.
“Our study shows that sensory substitution based on intraneural stimulation can deliver both position feedback and tactile feedback simultaneously and in real time,” said Silvestro Micera, one of the leaders of the research. “The brain has no problem combining this information, and patients can process both types in real time with excellent results.”
A good deal of training is still necessary for patients to learn how to interpret the signals and to adjust to the arm. Nevertheless, the two people that went through the training using the new device were able to accurately feel the nature of objects about three quarters of the time.
Prosthetic with Sense of Touch Lets Patients Know Its Location [Medgadget]