Cynthia Chestek: Lifelong Maker Uses Brain Waves to Control Prosthetics

March 23, 2020
Written By:
Mike Wood

Cynthia Chestek

Mike Wood: Welcome back to another episode of Michigan News Beyond the Headlines. I’m Mike Wood. I’m a video producer and I also run the Michigan news studio here on the campus of the University of Michigan in Ann Arbor. Our studio puts U of M faculty on the air, on major radio and TV networks around the world. But today, we’re going Beyond the Headlines. Cynthia Chestek is an associate professor of biomedical engineering here at the University of Michigan. Her team, including plastic surgeon Paul Cederna, have developed a process to help patients who have had a hand amputated control prosthetic devices using nerve signals from their brain. And she’s here with us now. Welcome, Cindy.

Cynthia Chestek: Thanks for having me.

Wood: Well, we first met just a few days ago when you came to the studio to be on a radio show on the CBC in Canada called Quirks and Quarks. And then a few days later, you were back to appear on Science Friday on NPR.


Wood: After years of doing your research in relative anonymity, what’s it been like to be thrust into the national and international spotlight?

Chestek: I’ve actually found it to be really overwhelming. Like, I’m— I’m really glad that the research is getting all the attention and that hopefully this will become widespread. But yeah, I’ve— I’ve had a lot of attention, a lot of people emailing me from my hometown, people’s parents hearing it on NPR. But yeah, overwhelming.

Wood: In addition to NPR and the CBC, I know the story also appeared in several major publications like Wired magazine and actually over 240 news outlets all over the world have picked up the story.

Chestek: Wow.

Wood: What have been some of the responses from old friends? Anyone, you know, like people surprised or— is that you?

Chestek: A lot of people that knew me when I was a kid. And so there. Yeah. And I also heard, our study participants are also like sharing this broadly and their families are hearing about it. And so I’m really glad that this is—yeah. Making— the word is getting around.

Wood: Well, that’s cool too, because your study participants basically they both had hands amputated.

Chestek: Yeah.

Wood: And so what your research has shown is that you can take a nerve signal— and it’s amplified and you can actually— someone can control a prosthetic device using their brainwaves, right? Yep.


Wood: That was Joe Hamilton, who is one of the study participants.

Chestek: Yeah, they can just think about moving. And we— we basically we came up with a method of making a nerve signal 10 or 100 times bigger. And that sort of unlocks a whole suite of, you know, machine learning tools that we can apply to those signals and try to predict hand movements. Such that the people don’t have to learn anything. They can think about moving. They can— you know, it is their brain. Even though its coming from the brain, through the nerves, through the small piece of muscle. But yeah, no, it’s— it’s working pretty well.

Wood: So you are an engineer and you work in engineering, but you were working with— who’s your partner in this?

Chestek: Yeah. Dr. Paul, Cederna in plastic surgery. And he has done this in hundreds of patients at this point, mostly to control pain. But a subset of those people work with us on these prosthetic control experiments.

Wood: So what did he do to enhance that signal, that nerve signal?

Wood: Well, so they developed this surgery. I mean, starting from I think he said the project started 12 years ago and I’ve been involved for the last eight or so. And they tried all kinds of really complicated ways of getting a signal out of a nerve back then and finally realized that this fairly simple surgery could reliably reattach the nerve to a muscle. And I got involved for actually taking these signals and controlling the prosthetic hand.

Wood: Wow, so what does he do? Isn’t it something involving a muscle?

Chestek: Yeah. So they can get the muscle from just about anywhere. So they’ll— they’ll take it from the thigh. Or if they’re doing the amputation right then— like it’s a traumatic case, they’ll take it from, you know, good muscle on the the limb they’re amputating. But it just looks like a small thin sheet of muscle. It looks like— it looks like it’s gonna be too thin. But then when they actually roll it up, it’s about a centimeter across and it forms this little muscle burrito around the nerve and the nerve will re-innervate into that. And then it eventually re-vascularizes and it becomes just like part of the normal muscle bed.

Wood: And then— and because of that, what does it do to the nerve signal or the strength.

Chestek: Yeah. So it makes it much bigger. And so specifically why that happens is, you know, you have this very tiny signal in a few micron wire and then that, you know, makes connections to lots of different bigger muscle fibers and they all fire at the same time. And so that’s how the signal gets ten to a hundred times bigger. Now that the signals are big enough, we have all of these algorithmic approaches developed for brain machine interfaces, which is sort of my— my day job. And so we’re— we’re good at interpreting neurons. Neurons in the brain and trying to turn that into a real-time control signal for hands and fingers and things like that. I mean, a lot of the you know, the code is very similar to what we’ve been doing in brain machine interfaces for years. And it’s also, you know, it’s the sort of the same library of algorithms that are used in satellites and autonomous vehicles. So it’s you know, it’s a lot of machine learning that’s been developed for control over the past ten years or so.

Wood: So when you started your career as an engineer, did you ever think your engineering would be integrated with human physiology or-?

Chestek: Yeah. I mean, I think I knew that I was gonna do something like that. So, you know, I’ve always— loved the electrical side. So all my background is in electrical engineering. And at some point I started learning about neurons in the brain. And it really struck me that this was, you know, really a subset of electrical engineering. Right. I mean, it’s entirely circuits and electricity. And, you know, they love electrical engineers and neuroscience labs. And that’s how I got my undergraduate research experience. But I think once you start recording from live neurons, there’s little that’s more cool than that. And so I was you know, I ended up in brain machine interfaces because that’s really where, you know, the engineering skillset gets applied to decoding these signals and so, yeah.

Wood: So the signals that our nerves are sending out and our brain is sending out— are similar to electrical signals that you’re looking at in regular machine engineering?

Chestek: I like to give a— you know when I’m teaching my students, I like to say that it’s not that we’re using circuits to make models of neurons. It’s that neurons are circuits. They are little electrical elements that are— exist so they can send electrical signals to other electrical elements. And this is what controls your body. And so it’s their circuits.

Wood: Wow. That’s crazy.

Chestek: We are so grateful to our participants to— they agreed to undergo an additional surgery in which we took very small wires, which are, you know, very similar to cardiac pacemaker leads, but very small. And they agreed to have these wires placed into the grafts. And also, if you other, you know, whatever muscles they had available also. And then they— they emerged from the arm on a little connector, and it goes under gauze. And when they come into the lab, you know, we’re very careful to keep it clean, but we can hook up a cable to that connector and then they can start controlling the prosthetic hand. And they have to stay six feet from a cart at all times because we’re recording on a medical amplifier. But, you know, they can— they can walk around and they can use the hand.

Wood: Wow. That’s amazing. And I’ve seen the video where they can pick things up and they can, you know, manipulate their thumb. Is that kind of key? The thumb?

Chestek: I think that is the most important new function here, is that they can actually orient their thumb with two degrees of freedom. And that’s because when you— when you think about it, the muscles for controlling your thumb are— a lot of them are inside your hand. So, you know, if I start pulling my thumb against the side of my hand, those muscles would be gone. If I if I lost my hand. So because we can get signals from the nerve to do that, we can now control the thumb in multiple dimensions. And so, you know, in real life the thumb has more than two degrees of freedom. But, you know, if I— that those two degrees of freedom are really helpful, if I go to grab an object, a lot of times it’s my thumb that’s going to rotate around the other side. And it’s really hard to orient these prosthetic hands without being able to move that thumb.

Wood: Wow. So what’s the next step? Obviously, this is really cool and it’s showing some promise, but they can’t get away from that cart in the lab.

Chestek: Yeah. So we’ve gotta get away, you know, to get people home. And so I think that everything we’re doing could be done in a conventional medical device. We just need to find a path from here to there. You know, we’re— we’re laser focused on finding a way to get people home. You know, whether it’s two years or now or five years from now or what.

Wood: So the typical prosthetic arm or hand that people have now, you know, they seem pretty, pretty complicated and stuff. What are the limitations with those versus what you hope to do in the future?

Chestek: Yeah. So there’s all these cool videos of prosthetic hands on YouTube. You know, when you see them moving all the individual fingers, that is usually done with a joystick or with with motion capture or something like that. And so right now, the state of the art that you can actually go home with from the clinic is a hand that can do a lot of different grass. But you still have to pull out your phone and change the mode to go from, you know, making a fist, to making a pinch, to making a point.

Wood: What do you think is the coolest thing about this research so far?

Chestek: It’s one of the first times we’ve seen nerve signals this large and probably there are other medical applications that are going to open up when you can get large signals out of the nerve, or large signals out of the brain. And one can foresee that there’s going to be additional medical applications other than these first few that we’re going after. So I you know, I have really high hopes for the next 10 years in neural engineering becoming really important to medicine.

Wood: So how did you first become interested in engineering?

Chestek: So, I mean, I was— I was a maker as a kid, so I always had a project going. I was always taking things apart. And I was always very crafty. I always liked big projects. And so, yeah, I mean, I think that, you know, I flirted with a lot of other career ideas, but ultimately kept coming back to, you know, the math and engineering.

Wood: Were you ever as a woman—were you ever intimidated to get into something that has been traditionally a male dominated field?

Chestek: Well, I mean, I guess I was a— I mean, so I was a tomboy. So that was— it wasn’t so much of an issue for me, I think. And I was also very competitive. And I think that, you know, if you have that, it makes it a lot easier. Yeah, I was you know, I had a number of classes there. I was the only woman in them. And I mean, you know, it is very difficult if you are intimidated by being the only woman in the room. But, you know, in general, I mean, I’ve always I’ve always loved it. I’ve always liked making things. And I think I’ve always appreciated, you know, how my love of making things means I should be an engineer. And these sort of inherent I mean, if you want a job that’s about creativity and also a job, I mean, if you’re very motivated to help people and aren’t satisfied with just helping the people in front of you. You know, this is a really influential job before changing things.

Wood: That’s awesome. So you told me about a—about a guy who had a big influence on you. A fella who actually went to the University of Michigan back in the 1940s and lived across the street from you. And you guys did some making.

Chestek: Yeah, absolutely!

Wood: Who was that guy?

Chestek: Yeah. So I’m thrilled to talk about my grandfather. When I was growing up, my my grandparents were across the street from me and he was this really cool guy. He was like this polymath because he was an engineer and a lawyer. Right. So like— so he was always making stuff. And we used to build model rockets and airplanes and he had like this giant shop. And that was from when he was an engineer. But, you know, later in life, he had gone on to become a lawyer and eventually a federal bankruptcy judge and had like, you know, a study filled with all the books of the great philosophers, and we’d spend hours talking about ethics and things like that. So, yeah. No, he was a major influence on me growing up.

Wood: So, yeah, you said he he had gone to the U of M. That’s kind of like your family has many people have gone on to higher degrees. And it kind of started with your grandpa.

Chestek: It did.

Wood: Coming to the University of Michigan.

Chestek: Yeah. So when I was a kid, he was just this really cool guy that lived across the street and let us get into all kinds of trouble. But as I became an adult, I learned more of his family story and I realized that the University of Michigan changed the whole economic fate of my family. And so I can explain how that how that happens. When he was a child, his father died. You know, leaving behind four children. And, you know, his mother had terrible difficulties. His older brother went to work on an oil rig. He got sent to live with his uncle on a farm. And, you know, well—while she got secretary training to try to, you know, get some income, he went through schooling thinking there was no way he was gonna go to college. Right. That the family— it was just not in the cards for him. You know, and he always loved the athletics, so that— that was his focus in high school. However, World War Two broke out and he found out about this really cool opportunity through the Navy’s V12 program. Annapolis wasn’t graduating enough naval officers during World War Two. So they, you know, it was free tuition, you know, and then you were slotted to be a Navy officer afterwards so you could choose engineering, medicine or foreign languages. He chose engineering. And so and he got free tuition and went to the University of Michigan. And also, while he was here, he played football. And he is probably prouder of playing football for the University of Michigan than anything he did afterwards, including going to Harvard and becoming a judge. Right, so he’s-?

Wood: That is so cool.

Chestek: Yeah. He married my grandmother, who was an immigrant from Russia during the Cold War. I mean, he was a really cool guy. And so, you know, and I did grow up with, like, you know, the leather football helmet around the house. And the TV was always on to the University of Michigan football game. My uncle went also. He tried to get my mom to go, but she went somewhere else. But, yeah, no Michigan’s always been a part of our family history.

Wood: Yeah. I looked him up a little bit. I saw he played in 1944 and 1945.

Chestek: Yeah. No, he was always super athletic. And even-

Wood: Oh he ran track here, too, I think.

Chestek: Yep. Yeah. No, he did. He did a lot of sports and he was you know, he— he also got the engineering degree. Like, you know, worked in Toledo as a civil engineer for a long time. I can remember when he was in his 70s, he was still winning handball tournaments. And so he played my brother, who was, you know, 25, and he beat him and he was telling him, wow, I must getting old because I really had to work for that. So, but yeah, he was a super and I mean, he was a pillar of the community, too, in Erie, Pennsylvania.

Wood: That’s neat. And you said he even wore a Michigan ring. Most of his life?

Chestek: Yeah. He wore a Michigan ring his whole life. And I didn’t think anything of it. I brought a friend home from college who pointed out he’s like, well, he went to Harvard also, why does he only tell, like wear the Michigan ring and talk about Michigan? And he’ll tell you he went to Michigan. You know, within ten minutes of meeting you so-.

Wood: Oh, that’s so cool.

Chestek: He was very proud of it. I mean, I think it’s, you know, looking back, this is where his life changed and yeah so-.

Wood: That changed your whole family, really? From then on with what he was able to do.

Chestek: Yep. Yeah. No. And he was then the sort of you know, he was the rock of our family. He placed such a high importance on education. I mean, it’s all— you know, all of his kids got some kind of graduate degree. It’s a lot of doctors and lawyers and Ph.D.’s.

Wood: That is amazing. So when you were out looking for a job or, you know, for your next challenge and U of M was one of the places you looked at. Did his affiliation and everything have any influence on it at all?

Chestek: At the time, I would’ve told you no. I would’ve said that, you know, I’m just looking for the best possible research program. But of course, Michigan does have a really good ranking in both engineering and medicine, and it’s great for neural engineering. So, you know, I was trying to be, you know, objective about it. But I mean, of course, yeah, I had grown up surrounded by Michigan paraphernalia my entire life, and I knew it would make him happy. You know, he unfortunately passed a few years ago. But one of the last conversations that I had with him when he was sort of still very lucid was getting to tell him that I had taken a faculty position at the University of Michigan. And so he was— he was so happy about it. And he was so proud of me. And so, I mean, I think. Yeah. No, he— he loved this place. Then he just started telling me all about Ann Arbor. And there’s so many locations around town that, you know, are still here. And, yeah, he loved his time here.

Wood: That’s awesome. So with the recent news with, you know, you being in the news and everything you guys have done, what do you think your grandpa’s reaction would be to that, having studied engineering here and now his granddaughter?

Chestek: He’d be asking me all kinds of specific questions about it. So if— if my grandfather was still alive, he’d want to know every piece of it. He— he spent his whole life still kind of thinking of himself as an engineer, even though he had been a lawyer for decades.

Wood: So you told me you’re a maker and you love doing stuff, and always have even as a kid with your grandpa. Do you still do any making? Or what kinds of things?

Chestek: Yeah. No, I’ve been a maker my whole life. And so right now, and I’m, you know, for a long time now I’m a medieval re-enactment enthusiast so that means-

Wood: So like the Renaissance Festival kind of thing, or-?

Chestek: No, no this is the Society for Creative Anachronism, which is more like, you know, it’s less about performance and more about doing it yourself. So I have this beautiful shop that’s my sunroom. It’s got, you know, it’s full of sunshine. And I do a lot of armor construction. I’m making a tent right now like a giant, you know, canvas tent. I do a lot of like weaving and other yarn crafts, a lot of sewing. And it’s— it’s a lot of fun. So I always have to be making something with my hands. Probably the thing I enjoy the most is the armor construction.

Wood: And what is that constructed out of?

Chestek: Well, so it’s a variety. I do work with steel as a steel leather. And, you know, it’s— it’s functional armor. So we do, you know, actual combat, which is a lot of fun. I have armored my whole family of four, including the children. I’m currently working on a Japanese kit for my eight year old. And so it’s— it’s a lot of fun, if you like, making stuff.

Wood: How old are your kids, and girl or boy?

Chestek: They are—I have a ten year old girl and an eight year old boy. They both hit people with pool noodle swords. And so it’s a lot of fun.

Wood: Pool noodle swords.

Chestek: And It’s adorable to have a little, you know, a gaggle of medieval children running around some of these events.

Wood: That is so funny. So what got you interested in that?

Chestek: Well, I mean, I think I always liked making stuff. I mean, even when I was in a dorm room, I would always find a way to have tools and a sewing machine in there, even though my quality of my tools and sewing machine have gotten a lot better over time.

Wood: Cool.

Chestek: But yeah, no, I’ve I have always been crafty.

Wood: But why the medieval stuff?

Chestek: Well I mean cause it’s fun to put your brain somewhere else and actually a lot of the fun for me is learning what technology used to be. And it’s always sort of better than you think it was. You know, you sort of think of people as having nothing before whatever technology we had here. But people have always been clever. And so the more you learn about how they made things, how they did things, you realize like, ha, actually they— this is not a bad pair of socks, right? And so, and there’s ways of getting to all these things. And, you know, I think society 2000 years ago was a lot more advanced than people think of it, as you know, due to the sort of the cleverness of the makers back then.

Wood: Do you— do you try to be historically accurate as much as you can? Or is it more like— like in how you manufacture it?

Chestek: Yeah. No, I mean, I think that I’m— I’m very interested in that. Like, you know, there’s some people that are more like, that will only use period correct tools. I use power tools.

Wood: I was going to say, you have got to use power tools.

Chestek: I just like— I’m a product crafter, so I like things to come about quickly. But I like them to, you know, look like that. I think my daughter put it the best when she said, like, if you know, if you have everything perfect and you can’t see anything modern, it feels really peaceful. So that— that’s how she put it in her ten year old, you know, way of thinking. And so, it’s a lot of fun.

Wood: That’s really cool.

Chestek: So, do you have any advice for, like, a young woman that’s, you know, maybe a freshman in college or high school kids just starting out trying to think about what do I want to do with my career and maybe engineering, but, you know.

Chestek: So, you know, I mean, really, the skill set is electrical engineering, which is— it is unfortunately still very low percentage women. So I’m always asking myself, you know, where are the missing women who, and I want to issue a personal invitation to, you know, the people that— that might have otherwise been engineers if— if not for some of the cultural barriers. And I mean, I think that, you know, who it is, is there’s a lot of people that love making things with their hands and they love having a big project that, you know, they’re working on with a lot of people and all the pieces, you know, come together and come to fruition

Wood: Problem solving.

Chestek: Yeah. And I mean, I think that is the core of engineering. I think that people think it’s math and code, and math and code are super important. But like, it’s not about loving math and code. Like, I don’t love math and code. I’m not sure anybody really does. I just love what it makes me able to do in terms of making things and making big things happen. And so I think that, you know, if I can make one cultural change, it’s, you know, to— to re-associate engineering with creativity and the love of seeing your ideas become reality. It’s really about that, you know, the act of creation. And so, you know, if you’re crafty, this is your personal invitation. And, you know, I think that you’re gonna be really pleasantly surprised. You know, once you get through that math and code, which is not fun for anybody, you know how much you love using it on the other side.

Wood: What do you think having more women and more diversity in general in a field like engineering does for the field of engineering?

Chestek: So I think it’s really important. It’s mostly important just because, you know, we’re— we’re missing people. There is— there’s a lot of ideas and creativity out there. It’s a major issue of equality. And, you know, you do have a lot of power to affect the future. And I think it’s, you know, in the interest of fairness that that should be shared also by by women and other underrepresented minorities. Keep in mind that research is all about finding the new way. And, you know, it’s— it’s you have one job, which is to do something that’s never been done before. And if you don’t keep recruiting people from a wide range of life experiences, you’re not going to find the new ways. And so I think diversity is extremely important for research in particular. I have enjoyed this career so much and I’ve enjoyed, you know, what the kind of things that you can sort of bring about. And so mostly I want to invite all of the young women out there to have this kind of fun as well.

Wood: It’s awesome. Well, thanks for sharing your story and chatting with us today.I really appreciate it.

Chestek: Sure thing. Thank you.

Wood: And thank you all for listening. I’d also like to thank the whole team here at Michigan News for their support of this podcast, including audio engineers Kirk Lawrence and Justin de Groat, Nicole Smith and Hans Anderson helped with digital strategy and marketing. And we couldn’t do it without the support from news director Laura Lessnau and associate news director, Bernie de Groat. I’m Mike Wood, be well and be safe. I’ll see you beyond the headlines.

Cynthia Chestek has turned her lifelong passion for “making” into a very successful career in engineering. Her team at the University of Michigan has come up with a way for amputees to control prosthetic devices using their brain waves.

Her family connection to the university started with her grandfather Warren Bentz, who attended in the 1940s.


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