Advances in limb prostheses have not obscured the fact that these devices still lack a sense of touch. Now, scientists from Northwestern University in Chicago have shown that transplanting the nerves from an amputated hand to the chest allows patients to feel hand sensation there. The findings could pave the way toward prosthetic arms with sensors on the fingers that will transfer tactile information from the device to the chest, making the wearer feel as though he or she has a real hand.
Earlier this year, Northwestern researcher Todd Kuiken and his colleagues at the Rehabilitation Institute of Chicago showed that a similar nerve-transplant approach could be used to intuitively control a prosthetic arm. In the new study, the researchers took the nerves that would normally carry sensory messages from the hand to the brain and implanted them into a patch of skin on the patient's chest. After allowing the nerves to grow for several months, Kuiken and his colleagues tested the sensory abilities of two amputees.
While both patients could tell the difference between different grades of sandpaper rubbed against their skin, they each developed varying senses of touch. One developed a broad sense of touch with sensation perceptions triggered in three fingers at the same time. The other felt sensation in different fingers linked to specific spots on her chest. The researchers are
now developing new components to add to prosthetic arms that will allow them to sense the environment and transfer those signals to the wearer's chest.