NOVA, the venerable science and technology series on public television, is currently running a documentary about people with robotic limbs called “Augmented.” The film chronicles the journey of Hugh Herr, a biophysicist who had both legs amputated at 17 after a climbing accident. Unsatisfied with conventional prosthetic limbs, he used his scientific acumen to develop what NOVA describes as “innovative prosthetic devices” that are controlled by the brain.
A member of Herr’s team of researchers, Dr. Shriya Srinivasan is a postdoctoral researcher and junior fellow at the Harvard Society of Fellows. Named to Forbes’ “30 under 30” list, she has a degree in biomedical engineering, with a concentration in biomaterials; her doctorate is in medical engineering and medical physics. Dr. Srinivasan’s research has included the development of novel neural interfaces, utilizing tissue engineering to more seamlessly connect human limbs to prostheses. The neural interfaces she has developed restore a sense of proprioception and touch from prostheses; they have been clinically translated to over 30 patients thus far.
In an interview with me conducted over email, Dr. Srinivasan described herself as a “passionate” and “hungry” graduate student keen on solving problems related to neuromuscular diseases, neural imaging, and prosthetics. She got involved with Herr in part because she saw an opportunity to leverage the knowledge she gleaned from her studies into real-world applications. It also affected her on a personal level. Her grandfather battled ALS—colloquially known as Lou Gehrig’s Disease—in the last decade of his life, and she became acutely aware the many burdens (emotionally, physically, and financially) associated with diseases that affect the limbs and nervous system. Dr. Srinivasan found herself motivated to learn more about these conditions and to find solutions for people afflicted with them.
Herr’s story was a perfect fit. “Hugh, having been a bilateral amputee [both arms or legs are fully or partially amputated], and his approach to studying [and] designing solutions for limb loss fascinated,” she said. “The lab was also filled with a wide array of disciplines—and I was compelled to learn and train in such an environment.”
The primary advance shown in the film is a new surgical technique that enables better interfacing with advanced prostheses, according to Dr. Srinivasan. The work to make it happen required a trans-disciplinary approach that integrated surgical reconstruction with engineering and design, crafted by a team of biomedical engineers and surgeons. The end result is a true tour de force of engineering. “The interface allows the patients to command a bionic limb and receive sensory feedback from it,” Dr. Srinivasan said.
Dr. Srinivasan told me Herr was “pleasantly surprised” by his new prostheses, adding the results “exceeded our expectations.” Herr plans on undergoing a modified version of the operation, developed by Dr. Srinivasan, which incorporates regenerative grafts to restore the capability of sensory feedback in his limbs. The process will allow his neuromuscular system to be “upgraded” and interface with robotic protheses. It gives an entirely new meaning to software updates.
All told, Dr. Srinivasan said rapid advancements in technology make possible the kinds of assistive devices used by Herr and others. In fact, the artificial limbs are theoretically more capable than human ones—with the caveat that this assumes seamless neural control.
The technology’s potential for future applications excites Dr. Srinivasan. “In the future, I imagine non-anthropomorphic designs that can augment functionality for humans,” she said. “These devices may also be used in patients with muscle weakness and serve to enable greater mobility and independence in their movements.”
Although the film centers on Herr, another person who features prominently in the film is Jim Ewing. In 2014, Ewing fell 50 feet from a cliff while rock climbing. He decided to participate in the groundbreaking surgical procedure pioneered by Dr. Srinivasan and Herr’s team, becoming the first recipient of a brain-controlled limb that restored his ability to rock climb again. Ewing even climbs competitively, having participated in the annual 24 Hours of Horseshoe Hell event held in Arizona. Ewing has known Herr for decades, and seeing Herr resume activity after his accident helped him understand that the loss of a limb did not mean “the end of an active life,” Ewing told me recently in a separate interview.
Prior to his accident, Ewing had only “peripheral” knowledge of accessibility and assistive technology. He saw conceptual devices while in engineering school, as well as following Herr’s adventures at MIT. The accident didn’t change Ewing’s outlook on accessibility; being an engineer, his view is that “we should always be pushing the boundaries of technology, to take [it] as far as we possibly can.”
Ewing made clear in our discussion he doesn’t actually have the robotic limbs for day-to-day living, as the lab wouldn’t let him keep the prototypes. Instead, he primarily uses them when researchers need to collect data. Ewing noted the differences between climbing with the robotic leg and the conventional one he typically uses.
“When I climb with the robot leg, it’s usually in a very controlled setting with specific data to be collected. It is fun to climb with it and what I’ve noticed is that I get to return to a more natural form of movement,” he said. “When I climb with my standard climbing leg, I sometimes have to position myself in awkward or unnatural positions in order to get the foot to stay on a hold. With the robot, I can position the foot just how I want in order to use a particular hold. The beauty of it is that I move the foot around using the same muscles I would have used if I still had my biological foot.”
Looking towards the future, Ewing told me he has multiple climbing trips planned, as he stressed the importance of keeping active. “It surprised me to learn just how much I had taken my mobility for granted,” he said. “It wasn’t until after my accident and I was unable to move without constant pain that I realized how important movement was to my mental health, never mind my physical health.”
“Augmented” is available now to watch on the PBS website or in the PBS app. The website version includes a full transcript.