Animal tests have already been conducted in which devices are implanted directly into the nerve to process and transmit signals wirelessly to an external device.
Other researchers are developing prosthetic skin which might wrap around a bionic limb and feed back sensory information to the nervous system, in theory enabling users to detect and feel objects.
The current generation of bionic hands can pinch or grasp using two or more electrodes fitted inside the portion of the prosthetic which fits over the stump.
Continue reading the main story“Start QuoteThe prosthetic skin would be full of electronic sensor function that would mimic the sense of touch we have in human skin”End QuoteStephanie LacourEPFL These electrodes are positioned to pick up signals from the user's peripheral nerve system that are naturally amplified by muscles in the stump.Progress is almost continuous. German company Otto Bock has developed a hand incorporating multiple electrodes which can drive wrist flexing and rotation.
While Scottish company Touch Bionics builds hands which use software to control individual finger movement, so that the hand can clasp around objects.
The surgical rewiring of nerves in an amputee can also offer a great deal, enabling those with no arm at all, for example, to drive bionic arms with elbow and hand movement.
But there are problems. Sweat on the skin or any movement in the prosthetic can disrupt the signal to the bionic limb. The prosthetics can also rub against the skin and cause discomfort and sores.
The next generation of bionics will try to overcome these problems and offer some sensory feedback to the user.
Wireless bionicsResearchers in Britain have already developed the Intraosseous Transcutaneous Amputation Prosthesis (ITAP), a rod screwed into the bone of an amputee onto which prosthetics can be fitted directly and securely, be they hands, legs or fingers.
The rod means higher loads can be carried than with traditional prosthetics which fit over the stump of an amputee like a glove. It also avoids friction between the prosthetic and the skin.
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