When bombs rocked the Boston Marathon last year, emotional reverberations were felt throughout the country: Communities held memorial races and sported Boston Strong ribbons and shirts, created makeshift memorials out of running shoes and American flags, donated money to families of injured runners. Engineers, meanwhile, got down to the nitty-gritty: Building better prosthetics for the 16 survivors who lost limbs that day.
"I think Boston raised awareness and is kind of inspiring for promoting recovery instead of focusing on the injuries," said Levi Hargrove, Director of the Neural Engineering for Prosthetics and Orthotics Laboratory at the Rehabilitation Institute of Chicago. Even though his lab hasn't worked directly with survivors, everyone in the field has felt the impact, he said.
"The survivors are getting back to their lives, working with scientists and therapists, because they're going to be living with this condition for a long time," Hargrove said.
Last month, one of those survivors took the stage at TED2014 and showed off her first-of-its-kind bionic leg that allows the professional ballroom dancer to rumba again. After Adrianne Haslet-Davis danced, she tearfully thanked Hugh Herr, director of the Biomechatronics Group at The MIT Media Lab and creator of the leg.
"All this emotion poured out," Herr said. "The very first time she [tried the new leg], she was ecstatic. She was so joyful about being on that dance floor and feeling that freedom again."
Herr, whose lab partnered on a fund to support the development of specialized prostheses for runners after the Boston attack, based Haslet-Davis's leg on data he gathered from dancers of a similar build and body type to Haslet-Davis's. He invited the dancers to his lab, which was tricked out with sensors to track exactly how they moved and how their forces impacted the dance floor.
The idea, he said, was to extract those principles of dance and imbed them into chips on the bionic limb.
"It's responsive in a way that's appropriate biomechanically," he said. "It doesn't simply output a traditional trajectory that she would have to keep up with like a wind-up toy. It's more like she is the lead and the limb is the partner."
The leg also has to be able to move like flesh and bone, so the lab uses a "smart" material that can flop and stiffen depending on the voltage being applied from the body.
David Sengeh, a graduate students who also works in Herr's lab, recently won the Lemelson-MIT National Collegiate Student Prize Competition for his work on improving the sockets used in prosthetics. Conventional molding methods often result in prostheses that don't fit precisely, and often cause pain. Sengeh uses MRI and a 3D printer to create a design interface based on individual data.
"The goal is to make a model where you can enter someone's data, press play and get a comfortable socket," said Sengeh, who tested the method on one of the Boston survivors.
The end result? Without the short skirt she wore at her TED performance to show off the leg, it may have been impossible to tell she wasn't born with that leg.