Fake Limbs That Work Like Real Ones

They may be on the verge of reality:

Victoria Turk heralds this breakthrough:

A real-life patient now has a fully-implanted “mind-controlled” robotic prosthetic for the first time. A Swedish truck driver who had his arm amputated over a decade ago became the first to properly get the arm, which is surgically implanted so as to be controlled by his biological nerves and muscles.

That means that he can control the arm in a pretty natural way, with the nerves and muscles sending signals to the prosthetic in order to move it. It’s like you’d move your own arm—you don’t have to really think about it. … The device is “osseointegrated,” which means it’s attached directly to the skeleton. The user doesn’t have to wear it all the time, however, as only a titanium implant is actually integrated with the bone, and the arm attaches to that.

Other researchers are working on prosthetics that feel like the real deal:

Restoring sensation has practical uses.

Modern prostheses are able, by reading electrical signals from muscles using electrodes attached to the skin of the missing limb’s stump, to perform tasks such as picking things up. Delicate tasks, however, can be tricky, since the user must rely on a combination of sight and experience to work out how much pressure to apply. For example, when Dr [Daniel] Tan blindfolded his volunteers and asked them to pluck the stalks from cherries without crushing the fruit, they succeeded only 43% of the time. But when he connected pressure sensors attached to the protheses’s fingers to the signal-generating machine, and gave them appropriate feedback, the success rate jumped to 92%.

Intriguingly, one unexpected benefit was that the device’s feedback banished the phenomenon of phantom limbs, in which an amputee perceives that his missing appendage is still present. Without the computer-generated sensations, both volunteers reported that their prosthetic hands felt like external tools (one described it as like an artificial hand that he was holding with his phantom hand). Switching the sensations on made the hand feel like an integral part of the body.