When one loses a limb, the brain is unable to fully process and still sends signals. It will continue to send signals to that limb—this is the leading cause behind phantom limb pain. While this occurrence may cause discomfort, it gives prosthetic researchers hope to use these signals to continue improving prostheses until they feel and act like a biological limb.
One of the most important senses that biological limbs offer is the sense of touch. However, most prostheses that are available on the market don’t have this feature yet. Researchers at Johns Hopkins University sought to restore the sense of touch to prosthetic users by testing and developing an “e-dermis.”
The e-dermis makes it possible for artificial limbs to detect the sharpness and curvature of objects. As of this writing, this technology is only available to upper-limb prostheses, particularly at the fingertips.
The e-dermis is made of rubber and fabric, laced with sensors that mimic nerve endings. It can recreate a sense of touch and pain by sensing stimuli and relaying impulses back to the peripheral nerves. The prosthetic user receives information as the e-dermis stimulates peripheral nerves through the skin in a non-invasive way through transcutaneous electrical nerve stimulation (TENS).
As a result, the prosthetic user can experience a spectrum of tactile perceptions, from light touch to pain caused by a stimulus. In a pain-detection test, the team determined that the test subject and the prosthesis were able to experience a natural reflexive reaction to pain while touching a pointed object and non-pain when touching a round object. However, the e-dermis is not yet sensitive to temperature.
The researchers plan to develop the technology further and understand better how to provide meaningful sensory information to prosthetic users.What do you think of this technology? Is this something that you would want in your prosthesis? Please share your thoughts in the comments section below.