New Prosthetics From MIT Transmit Sensory Information Like Real Limbs

Bionic limbs that can be controlled by the wearer's natural electrical signals have been around for a while, but prosthetics that send information the other direction—transmitting sensations to the nervous system—are less common. In a talk given at TED 2018 in Vancouver, an engineer and double-amputee presented a new type of technology that does exactly that, Fast Company reports.

Hugh Herr lost both his legs below the knees after contracting frostbite during a mountain climbing accident in 1992. Today, he's in charge of the Biomechatronics Group at MIT Media Lab where he and his team develop high-tech prosthetics that can help people like him.

The synthetic legs Herr currently wears are sophisticated: Outfitted with around 24 sensors and six microprocessors, they can detect subtle electric signals from his nervous system and move accordingly. But the sensation of stepping forward, or stepping on something soft rather than hard, is still muted. (This lack of footstep feedback has been a problem for people with paralyzed limbs testing exoskeletons as well.)

With the new technology from MIT, a prosthetic foot would send the wearer sensory feedback about their environment similar to how a flesh-and-blood limb would. For this so-called neuro-embodied design to work, the way doctors treat amputee patients first needs to change. The current protocol with amputations is to truncate the tendons and nerve endings where the limb ends to lessen sensation there. For a patient interested in using MIT's prosthetics, doctors would need to leave those nerves and muscles alone so they can connect to the new limb and continue to transmit sensations.

Herr's friend Jim Ewing, a fellow mountain climber, became the first person to receive the new amputation treatment and the high-tech prosthetic last year. With his new integrated synthetic foot, he can now navigate complicated terrain like steps using sensation alone, and he can even climb cliff faces.

The technology is potentially life-changing for people who have lost a limb, but Herr says it's not limited to that group. He envisions a future where cyborgs are a part of everyday life. "I believe humans will become superheroes," Herr said in his TED talk. "During the twilight years of this century, I believe humans will be unrecognizable in morphology and dynamics from what we are today."