June 21 (UPI) -- Engineers have developed an electronic "skin" that allows prosthetic hand users to perceive a real sense of touch.
The e-dermis, when layered on top of the prosthetic hands, restores the sensation of touch through the fingertips. Engineers at Johns Hopkins University published findings Wednesday in the journal Science Robotics.
"This is interesting and new because now we can have a prosthetic hand that is already on the market and fit it with an e-dermis that can tell the wearer whether he or she is picking up something that is round or whether it has sharp points," Luke Osborn, a graduate student in biomedical engineering at Hopkins, said in a press release.
Osborn said the method was inspired by human biology, with the complex network of receptors for touch and pain sent to the brain being imitated in e-dermis.
Working with researchers from the Singapore Institute of Neurotechnology, the Hopkins engineers developed a biological template.
The e-dermis conveys information to the amputee by stimulating peripheral nerves in the arm in a non-invasive way -- through the skin.
"For the first time, a prosthesis can provide a range of perceptions, from fine touch to noxious to an amputee, making it more like a human hand," said senior author Nitish Thakor, a professor of biomedical engineering and director of the Biomedical Instrumentation and Neuroengineering Laboratory at Hopkins.
He also is co-founder of Baltimore-based Infinite Biomedical Technologies, which provided the prosthetic hardware used in the study.
By tracking brain activity via EEG, the team determined that the test subject perceived these sensations in his phantom hand.
Then, researchers connected the e-dermis output to the volunteer with a noninvasive method known as transcutaneous electrical nerve stimulation, or TENS. The volunteer detected pain while touching a pointed object and non-pain when touching a round object.
"After many years, I felt my hand, as if a hollow shell got filled with life again," said the anonymous amputee who served as the team's principal volunteer tester.
The volunteer tested the device for one year and four other amputees volunteered in other experiments for sensory feedback, with the exception of temperature, which the e-dermis is not sensitive to.
Researchers say they envision developing similar systems in lower limb prostheses.
They also said the process could be used for people without artificial limbs, including astronaut gloves and space suits, Osborn said.