The goal of prosthetic design always has been to restore the function lost due to the limb loss. Unfortunately, a manufactured device has not been able to completely mimic the movements and form of a human limb. Recent technological advancements are forcing the boundaries of prosthetic design into realms thought to be that of science fiction.
Restoring the sense of touch through a prosthetic had been thought to be an impossible task. The nervous system was presumed to be too complex to be harnessed and routed through a prosthesis. Researchers at the Rehabilitation Institute of Chicago, searching for ways to utilize muscles to control a prosthesis, have stumbled upon a method of restoring the sense of touch for some amputees.
During the surgery, known as targeted reinnervation, the motor nerves in a nearby muscle are deactivated. The nerves endings from the newly amputated limb (in this case always an arm) are rerouted and embedded into this muscle. With time, the nerve endings acclimate to their new host muscle.
Researchers discovered that stimulating the area of the rerouted nerves created a touch sensation for the amputee. Experimenting with a variety of systems to stimulate the area, including electrodes and minuscule robots embedded within the socket, amputees have reported feeling temperature, textures and pressure variations.
At this time, research is limited to upper extremity amputees. Because the nerve rerouting must occur at the time of the amputation, it has not been attempted on experienced amputees. Although the pool of those who may benefit from this research immediately is small, the long term effects have the promise of impacting prosthetic design in the future.
To read more about targeted reinnervation and the impact on restoring sensation, visit: Scientific American or USNews.