Triumph of the Bionic Limbs
From: Discover Magazine - Jan/Feb 2013 - page 84
By: Adam Piore

In August Oscar Pistorius, a South African double amputee, sprinted into the
400-meter semifinals - and into Olympic history - on carbon-fiber feet. In
November Zac Vawter climbed to the top of Chicago's Willis Tower (formerly
the Sears Tower) on a bionic leg controlled by his thoughts. The events were
triumphs for both the athletes and the army of prosthetics engineers working
behind the scenes. Pistorius's feet were so effective that some questioned
whether they provided an unfair advantage on the track. The prosthetic worn
by Vawter, a software engineer, has even bigger implications for commonplace
amputee challenges like walking up hills and stairs.

After losing his right leg in a motorcycle accident, Vawter underwent an
experimental technique called targeted muscle reinnervation. Stray ends of
nerves at the amputation site were redirected into muscle elsewhere in the
leg. When his brain sends messages down those nerves, the muscles contract,
amplifying the signal. Engineers at the Rehabilitation Institute of Chicago
put electrodes on Vawter's thigh to detect the contractions and used a
computer chip to translate them into commands for his motorized prosthetic.
"We learned what patterns look like when Zac wants to bend his knee or climb
the stairs," explains lead scientist Levi Hargrove.

As machines become better integrated with the human body, we are glimpsing a
future without disabilities, says Hugh Herr, a pioneering prosthetics
researcher at MIT: "Society should begin to question social norms that label
amputees as disabled."

Links:

Zac Vawter climbs 103 floors of Chicago's iconic Willis Tower with bionic leg
http://www.nydailynews.com/news/national/man-bionic-leg-climbs-103-floors-article-1.1196727

Levi Hargrove
http://www.ric.org/research/centers/cbm/staff/Hargrove/