Hugh Herr discusses bionic limb technology: Highlights from his Reddit AMA
Hugh Herr is a faculty member at the Massachusetts Institute of Technology (MIT) who heads MIT’s Biomechatronics Group and co-directs the Center for Extreme Bionics. He suffered bilateral below knee amputations as a teenager due to frostbite while rock climbing and has devoted his life to developing prosthetic technology. Herr recently participated in a Reddit AMA (Ask Me Anything). The following are highlights from the interview session.
How did you overcome losing your legs at 17? Im sure it was a lot of struggle in the beginning. Can you tell us how your feelings about the tragedy changed over the years? (Reddituser2460155)
HH: After my mountain climbing accident, I was extremely angry at myself for having caused the accident, and the death of a rescuer, Albert Dow. Because of Albert’s ultimate sacrifice, I felt it was my duty and obligation to invest my body and mind, and all of my energies, to improving the world in some way. The way that I chose was to improve technology for the disabled. I believe I dealt with my accident by embracing Albert’s legacy and the challenge of eliminating disability through technological innovation. As I walked down that road, I also began to heal.
What is the biggest misconception or hype regarding prosthetics? (MarsNirgal)
HH: Hollywood has given us the impression that synthetic robots and bionic appendages will be awkward, unnatural and machine-like. I do not agree with this vision of the future. We can as designers and technologists embed the fundamental nature of humans into the designed world. In the future as we construct, certainly in the realm of bionics — these devices will move like us, will think like us, and will even feel like us. In that future, the distinction between what is biological and what is not, what is human and what is not will be forever blurred.
How well do current bionics wear with time? In other words, how much maintenance and replacement do current technologies require, and how do you see this changing in the future? Also, about how long would you estimate it will take for hand-replacing bionics to roughly match normal dexterity and responsiveness? (Bocab)
HH: Excellent question! The performance of biological systems is of course phenomenal, one characteristic of animals is extraordinary robustness or durability. Sometimes we go 80 years or more without maintenance or repair. Engineered machines go a very short time before needing repair — for example the bionic limbs that I invented and am wearing right now (BiOMs) are designed to work and be functional for only 5 years. To get a machine to emulate a biological body part and to go for more than 5 years is an extremely hard technological challenge. To truly emulate biological function, biological durability would require that the machine repairs itself. Before we have this, our machines will be very limited in their capacity.
I’m a materials chemistry Ph.D. student, and I’m interested in learning what opportunities there are for new materials in the field of prosthetic technology. What types of materials are needed in this area, i.e. what properties would the structural and active parts of an artificial limb possess in an ideal future world? Is there a type of smart material (a material that can adapt its properties to its environment) you can envision that could be useful right now? (Zoxid7)
HH: Improvements in materials is of course critically important to the field of bionics. One example that comes to mind is osseointegration. Today osseointegration involves a titanium shaft passing through the skin membrane and into the residual bone. The osseo implant serves as a mechanical mounting surface for an external bionic limb, such that when a person walks, for example, the loads of walking are transferred directly to the person’s skeleton. The osseo implant can also be made to have a hollow core, enabling the passage of wires from muscles/nerves inside the body through the osseo conduit to an external bionic limb.
A critical challenge of an osseo implant has to do with its material properties. With today’s osseo implant design, it is recommended that the user not take part in athletic activities, for fear that the high stresses on the osseo implant may cause damage. In the field of bionics, what we desire is a novel biocompatible implant with exceptionally high material strength and fatigue life such that the user could, once again, pursue their athletic endeavors.
Do you think humanity will ever get to that point where prosthetic limbs are not so much a replacement for what’s lost, but rather an upgrade of one’s body? And do you think it would be ethical? (Dvalentined666)
HH: Yes, I do believe that modern technology will ultimately enable human augmentation. Recently my laboratory in 2014 developed the first leg exoskeleton to augment human walking. So human augmentation is already being demonstrated in the world! Is it ethical? I personally accept the notion of human augmentation, as long as it doesn’t mitigate individual freedoms. There are some forms of augmentation that would negatively impact us, and have the potential of collapsing human diversity. For these types of augmentation technologies, I am passionately opposed.
This Reddit AMA occurred on August 22, 2016.
