Tricking amputees into accepting their prosthetic

One of the biggest challenges faced by amputees who use prosthetics is getting over the feeling that their prosthetic is not part of their body. It’s partly a counter-intuitive problem: of course, the prosthetic is not part of the body, but it’s essential for the user to imagine it is if they are to get the best use from it. One particular problem is that amputees can often ‘feel’ their missing limb; or at least, a distorted version of it.

Researchers at Lausanne Polytechnic University (EPFL) have experimented with sensory illusions to determine whether amputees’ nervous systems can be “tricked” into accepting the prosthetic limb. The technique relies on the axiom that “seeing is believing”.

This can itself be a reason that amputees opt out of prolonged use of prosthetics, especially of artificial hands: essentially, their own perception of the missing limb – or the sensation of it – does not match up with what they can see of the prosthesis. Part of the problem is that the phantom limb often perceived by amputees is much smaller than the actual lost limb; and as the prosthetic does not provide sensory feedback, the user can only tell it is being used correctly by watching it. The mismatch between vision and sensation can be an overwhelming stumbling block.