Fig. 3

Examples of proprioception restitution strategies for coding positional and movement-related information. Stimulation devices have been illustrated as applied to a single limb to simulate their simultaneous use, but their choice will inevitably depend on the user’s level of amputation and will therefore be tailored to the individual. The degree of grip aperture has been encoded into the movement of a skin-stretch stimulation device, whose position on the user’s skin can be employed to infer the state of the prosthetic hand, thereby reducing the need for careful vision inspection [73]. Also, the prosthetic wrist’s prono-supination state has been fed back by activating a dedicated combination of electrodes on the user’s forearm [86]. Vibrotactile motors around the arm of the user have been used to encode discrete angular positions of the controlled myoelectric elbow [87]