‘Touchy-feely’ bionic hands come closer to reality

LIVINGSTON, SCOTLAND - APRIL 23:  Patrick Kane is fitted with the new Touch Bionics prosthetic hand on April 23, 2013 in Livingston, Scotland. The new i-limb ultra revolution has a powered thumb rotation along with multiple grip patterns, which enables users to perform daily activities easier than with previous prosthesis.  (Photo by Jeff J Mitchell/Getty Images)

From Business Standard

“Touchy-feely” bionic hands have come closer to reality as researchers are exploring new approaches to designing prosthetic hands capable of providing “sensory feedback.”

University of Michigan’s Paul S. Cederna and colleagues wrote that emerging sensory feedback techniques will provide some sensation and enable more natural, intuitive use of hand prostheses, adding that these breakthroughs pave the way to the development of a prosthetic limb with the ability to feel.

As per the researchers, upper limb loss is a “particularly devastating” form of amputation, since a person’s hands are their tools for everyday function, expressive communication and other uniquely human attributes. The functional, psychological, economic, and social impact is even greater since most upper limb amputations occur in young, otherwise healthy individuals.

Current robotic prostheses approach the fine dexterity provided by the human hand, but these advances have outpaced developments in providing sensory feedback from artificial limb. The lack of sensation is the key limitation to reestablishing the full functionality of the natural limb, they noted.

Providing some sense of touch to the artificial hand would lessen the cognitive burden of relying solely on vision to initiate and monitor movements, while also providing tremendous psychological benefits for patients.

The review focuses on recent and emerging technologies to create sensory interfaces with the peripheral nerves to provide feeling to prostheses. Already in use is a technique called sensory substitution.

A promising newer 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 signaling using specific light wavelengths.

Researchers wrote that 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 study is published in Plastic and Reconstructive Surgery.