Controlled prosthetic feedback brings a steady touch

A patient performs various everyday tasks with a sensory control module integrated with his prosthetic arm (Credit: Aadeel Akhtar, University of Illinois)

Modern prosthetic arms are often equipped with electrodes that provide the wearer with a degree of ‘touch’, with sensors in the fingertips sending current to electrodes on the limbs. Light pressure will produce a light sensation, and a stronger current indicates a heavier touch. But the electrodes can sometimes become detached, or a build-up of sweat can affect their function. When this happens, amputees can be subjected to uncomfortable electric shocks as the current builds up in a single spot.

To counteract this, a team at the University of Illinois devised a controller that monitors what the patient is experiencing, automatically adjusting the current level to deliver steady feedback. Even when sweating or the electrodes are 75 per cent peeled off, the user feels the appropriate amount of current.