Orthotics are wearable medical devices that go places like your knee or ankle. For those with cerebral palsy, they can be a lifeline.
However, current orthotics available can be heavy and bulky. But Sam Hopkins, a doctoral student of mechanical engineering at Northern Arizona University, has a new model that could help fix that.
Hopkins is working to build a new orthotic ankle device that would be more flexible and adaptive to changing terrain. He’s recently been granted funding from the National Institute of Health to do it at professor Zach Lerner’s Biomechatronics Lab.
Hopkins joined The Show to share more about how this new device would work and how Iron Man inspired him to do this work.
Full conversation
SAM HOPKINS: So these are orthotics that are essentially ankle braces. They’re kind of like wearing a ski boot, for example. Now, you don’t normally wear a ski boot through your everyday life, but we use them for people who have mobility disorders like cerebral palsy. That’s a neuromuscular condition that happens shortly before, during or after birth that leads to some complications with muscle development and control. Typically, that impacts ankle function. And so what that looks like is typically something like a crouch gait, where an individual walks with their knees extra flexed. And ankle-foot orthosis gives that person more stability and support for that ankle.
LAUREN GILGER: So, OK. So these I think people might have a picture in their head of what they look like, how they work. Tell us a little bit about you and how you got into this work, though. Do you have any kind of personal connection to these kinds of devices? You know anyone who’s lost mobility in their life?
SAM HOPKINS: So I got into this because I was really fascinated with the concept of Iron Man as a kid —
LAUREN GILGER: Like Tony Stark Iron Man?
SAM HOPKINS: Exactly. And when I was about 13, my grandfather was affected by esophageal cancer. Now, it was a pretty slow process for him as he lost his mobility, because he couldn’t really eat, stay active and chemotherapy took a toll on his body. And so that meant for my family, we had up to three people moving him around the house at any given time. And it was really difficult to see him just navigate life always having to be essentially carried or picked up out of bed. ... So around then is when "Iron Man 3" came out, and I was like, “Oh wow, that’s really fascinating. I want to be able to do that so I can help my grandpa stay active.”
LAUREN GILGER: That's really cool. So now you're you're doing the work at NAU there as a doctoral student. Tell us a little bit about how these current kind of ankle brace, ski boot-style orthotics look and function. Like are they clunky? How do they work for folks?
SAM HOPKINS: So I say ski boot because it’s really something that most people have an idea of, but a ski boot’s really thick, big. Ankle-foot orthosis is actually going to be something thinner, but it’s just the rigid plastic part of the boot, essentially. So it can slide into people’s shoe. That gives them the extra support, and it’s pretty light, which is what we want when you’re actually wearing a device.
The problem comes in in that the orthotics don’t adapt or adjust as you move about your daily life. You know, as you’re walking, you’re driving, you’re hiking — your ankle’s doing a lot of different things. But an orthotic is just a plastic shell that gives you support, but it doesn’t really do a lot more than that for you, and it actually restricts your ankle.
LAUREN GILGER: Hm. So you’re working on one that’s made of carbon fiber. You’re 3D printing those parts, right? How is yours different?
SAM HOPKINS: So ours is robotic. It’s adjustable, so it can be stiff when you need the support, but it can also be flexible when you need that ankle motion for like driving or walking up and down stairs.
LAUREN GILGER: How did you come up with this specific model and kind of develop it? Did it take a lot of trial and error?
SAM HOPKINS: So when I got to the lab, Dr. Lerner already had some ideas in the back of his head for what to do, and I was able to create my device based on some of his concept work. What that looks like is we have a very stiff material, and we’re able to adjust that material property on the fly while you’re walking. And that’s where the real novelty of the device comes in.
LAUREN GILGER: Mm-hmm. So it’s lightweight in a way, but it’s also sort of adjustable. There are springs involved in this. Is it motorized?
SAM HOPKINS: It’s a spring. We use actually tiny servomotors to reconfigure how that spring works, but we’re not directly motorizing your ankle with this device. On the other hand, we do have devices that are motors that we attach essentially to your ankle, so that way you’re getting that assistance directly from that motor rather than a spring.
LAUREN GILGER: Yeah. You’re working on, it sounds like, other sorts of, you know, devices, things like, you know, Iron Man might have used, right? Tell us just about the world in which these kinds of devices exist. Like, I don’t think most people know what goes into creating something like this so that somebody can, you know, have a little bit more mobility.
SAM HOPKINS: So the concept is actually really simple in that we are essentially replicating what your body is already doing. You have bones that provide support to your body, and you have muscles that allow you to move. Well, what we do is take our rigid carbon fiber parts and strap them next to your joints, and then use the motor as essentially almost like a a secondary joint.
And that’s why we call them exoskeletons ... because they function exactly like your normal exoskelet — your normal skeleton and your normal muscles, but they give you that assistance in parallel, essentially, right next to your own joints.
LAUREN GILGER: Right, on the outside there. That’s fascinating. Have you ever tried it on? What’s it feel like?
SAM HOPKINS: Yes. Oh, I have to wear them all the time. ... It’s more subtle. You feel it kick in, but as you walk you get, “Oh, OK. I don’t really know what it’s doing for me.” It’s actually the moment you turn it off that you really feel, “Whoa, like I’m suddenly walking through molasses without it.”
LAUREN GILGER: Oh, that’s fascinating. Is it like when you walk on one of those moving walkways at the airport and then you step off and realize you’re slow?
SAM HOPKINS: Exactly, exactly like that.
LAUREN GILGER: So you have won a fellowship from the National Institutes of Health to continue this research. What’s your goal here?
SAM HOPKINS: This fellowship is actually a predoctoral training grant, they call it. So it’s designed to give me more experience to grow as an ... independent researcher. So I’m essentially leading this project, but I’m also networking with a local prosthetist and orthotist and other professors from different universities like University of Michigan and University of Washington, so I can really get the experience of developing my own hands-on project. Where I want to go with that is, you know, a professorship or an industrial engineer scientist position.
LAUREN GILGER: So in the end, do you hope that you and this kind of broad team of people you’re working with on this can kind of reenvision, remake the way that these kinds of devices work for folks?
SAM HOPKINS: Exactly. We want to develop something that’ll be more effective than the current technology.
LAUREN GILGER: All right. Sam Hopkins, doctoral student at NAU, joining us to talk about this project. Sam, thank you very much. Congrats on the fellowship and good luck.
SAM HOPKINS: Of course. Thank you so much, Lauren.
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