We’ve covered dozens of advanced hand and arm prostheses on these pages, many of which are capable of rather accurately recreating the movements of natural limbs. Looking like they can challenge the abilities of healthy persons, these devices continue to be limited due to the seemingly archaic methods used to control them. Skin electrodes, the most common interface, are prone to make mistakes because the skin constantly moves in relation to the muscles from which the signal is read. In addition, salty sweat complicates matters since it changes the electrical properties in the interface between skin and electrodes.
Researchers at Chalmers University of Technology in Sweden believe much better results can be achieved by using osseointegration coupled with direct implantation of electrodes onto muscle nerves. Not only would physical coupling be improved and signals would arrive with more consistency to the prosthetic, the device would be able to signal back and provide constant feedback to its wearer. So, for example, once a prosthetic hand has grasped a object, the user would feel it relatively naturally instead of receiving the commonly used audio, visual, or tactile feedback. The team is gearing up for installations of their system on initial amputees this coming winter.
Chalmers University of Technology: Thought-controlled prosthesis is changing the lives of amputees.