Prosthetic hands with a sense of touch, soon

Washington: Researchers are exploring new approaches to design prosthetic hands capable of providing "sensory feedback".

Providing sense of touch to the artificial hand would lessen the "cognitive burden" of relying solely on vision to initiate and monitor movements.

Such artificial limb will provide "tremendous psychological benefits" to patients.

"Emerging sensory feedback techniques will provide some sensation and enable more natural, intuitive use of hand prostheses," said Surgeon Paul S. Cederna from the University of Michigan.

"The lack of sensation is the key limitation to re-establish the full functionality of the natural limb."

The team is working on a technique called the sensory regenerative peripheral nerve interface (sRPNI), in which a "bioartificial interface" transfers sensory signals directly from a prosthetic sensor to the remaining nerve.

Other techniques use various types of implanted neural interfaces -- electrodes placed in or around the nerves -- which are stimulated by sensors on the prosthesis.

These direct neural stimulation approaches show promise in enabling patients to feel object characteristics such as stiffness, shape, size, or to control fine-motor movements without visual cues.

Another new technique is targeted muscle reinnervation (TMR), in which nerves are transferred to provide sensation to intact muscles and overlying skin.

Another "next generation" approach is the use of optogenetic technology to control nerve signalling using specific light wavelengths.

"The ultimate goal is to develop a prosthesis that closely mimics the natural limb, both in its ability to perform complex motor commands and to elicit conscious sensation," the authors said.

"These new techniques like TMR, sRPNI and optogenetics represent the wave of the future, paving the way to more intuitive prosthetic control through sensory feedback."

The study appeared in the journal Plastic and Reconstructive Surgery.