Advanced Prosthetic Limbs Enable Sensation of Touch

DARPA advanced prosthetic armA team of clinicians, engineers, and scientists at the University of Pittsburg is developing technology that could allow amputees to have more natural control and even feel the sensation of touch with prosthetic limbs. Today’s artificial limbs do not provide sensory information to users, which means that even the most advanced prosthetic limbs feel numb, so they function more like tools than body parts.

Researchers are currently working on pinpointing the electrical signals that occur in the body’s nerves. To gather baseline data, they are mapping electrical signals and muscle movement from volunteers who have fully functioning arms, via electrodes that are implanted into forearm muscles. Additionally, they are testing a group of volunteer amputees by simulating the portion of the spinal cord nerves that are responsible for forearm and hand sensation. If an electrical signal is detected in the required nerves, the amputees are deemed candidates for feeling the sensations of touch with the new prosthetic limbs.

The human body’s Central Nervous System receives information from sensory nerves and generates movements by sending signals to muscles via motor nerves. The new technology would use electrodes implanted in amputees’ remaining forearm muscles to wirelessly transmit motor signals to a prosthesis. The electrodes will connect to the prosthesis, which will then be able to accept the brain’s movement and sensory signals. Similar prosthetic limbs on the market use electrodes applied to the skin. In this new system, implanted electrodes will allow more direct control and, if all goes according to plan, the sensation of touch.

Current research is focused on prostheses for below the elbow, but if tests are successful, the new technology could be applied to prosthetic legs and feet in the future. Last year the project received more than $110 million in funding from the Defense Advanced Research Project Agency’s Hand Proprioception and Touch Interfaces program, the National Institutes of Health, the National Science Foundation, and the Food and Drug Administration.

Source: NPR WESA | Image by DARPA