Six sensors are attached to the sole of the prosthesis to provide nerve stimulation on the residual limb. Photograph courtesy of the University of Applied Sciences Upper Austria.
Austrian researchers have fitted a man with a sensory-enhanced prosthetic leg that can produce feeling, which they say increases safety and reduces phantom limb pain. “The reestablished transfer of information also contributes to a more natural integration of the prosthesis into the body concept of the patient and, in this case, has led to the complete disappearance of previous long-lasting pains,” announced the University of Applied Sciences Upper Austria (FH Upper Austria). The researchers, who are with the Research Group for Arm and Leg Prostheses Linz (ReALL), Department of Medical Technology at FH Upper Austria, provided a live demonstration of the prosthetic leg at a press conference in Vienna, Austria, on June 8.
Prior to the fitting of the prosthetic device in laboratory conditions, the patient underwent targeted sensory reinnervation, a selective transfer of nerves from the residual limb, during which the sensorial nerve endings that once relayed communication from the sole of the natural foot were reactivated to serve as an indicator for pressure on the sole of the prosthetic foot. Six sensors were then attached to the foot sole of the prosthesis; the sensors are linked to stimulators inside the socket, allowing the patient to receive sensations from the prosthesis. The neural interface can then communicate feeling from the sole of the user’s prosthetic foot, providing information about the type of ground that he or she is walking on, and awareness of obstacles, which can reduce the risk of falls.
The initiator of the research project, Hubert Egger, PhD, a professor of prosthetics with the Department of Medical Engineering at FH Upper Austria, also headed the development of a prototype of a mind-controlled and sensory-enhanced prosthetic arm as the head of research and development of Ottobock, Duderstadt, Germany.