As Danica Cooley ’20 makes a fist, opens her hand, and pulls her fingers into the shaka sign, a black robotic duplicate of her hand and forearm smoothly mirrors her every movement.
A black armband on Cooley’s arm is reading her brain’s signals, expressed by muscle movements in her upper arm, and transferring those signals to the robotic prosthetic. She maneuvers the artificial extension of herself with the curious fascination of a scientist—she’s majoring in kinesiology, with a particular interest in prosthetics.
Like a robotic arm, no patient treatment is one size fits all. In the process of creating and testing her own prosthetic arm, Cooley has found that the learning curve of adopting a robotic prosthetic is different for everyone. As an aspiring physical therapist, Cooley has been investigating that curve so that she can better empathize with her future patients and guide them through the treatment best suited for them.
Myoelectric prosthetics—which use muscle signals to control a device, like the arm Cooley produced—are a big deal in the field, right now. Scientists around the country are testing their possibilities, from whether they can be so fine-tuned that a cellist can once again play classical music, to whether simplified versions can be so cost effective that they’re widely available in developing countries. Cooley is adding to that ongoing, national experiment with an important, patient-centered question: how can clinicians tell if a myoelectric prosthetic is right for a particular patient, before they buy it, struggle, and potentially abandon it?
Cooley was able to produce a myoelectric arm piece by piece with the College’s 3-D printer. Even with an open-source code for the design as a foundational starting point, 3-D printing a robotic arm is an exercise in diligence and troubleshooting. Cooley would program the printer to produce a piece and come back the next day, only to find the plastic component had come out too soft and weak, or clumped together with another piece.
This intricate level of 3-D printing is hard, but it’s worth the effort. The same is true of innovation.
“This is my personal, professional opinion: if you’re just doing something that works with the first effort, you need to step your game,” said Joshua Haworth, assistant professor of kinesiology, who mentored Cooley through the project. Becoming an innovator is difficult. But the learning curve gives students the professional skill set of perseverance and, when they push themselves, they rise above the millions of people who settle for simply accomplishing what’s already been done.
Cooley persisted, and it paid off. After a lot trial, error, tweaking, hopeful days and deflating defeats—she finally had a fully formed human forearm and hand, sleek black and ready for experimentation. With the assistance of computer science alumnus Julian Droetti ’18 on writing the code that controls the arm, Cooley successfully programmed the arm to respond to her movements.
“It was crazy. Professor Haworth and I just started freaking out,” Cooley said. “It’s kind of like your child when you watch it walk for the first time. That’s a little dramatic, but that’s how we felt.”
To better understand how users engage with the technology, Cooley invited people to wear the armband and use her newly minted robotic arm. Strapped in, they went through the motions: moving their arm, making a fist, picking up a coin. The motions were simple enough, but Cooley kept an analytical eye out for who demonstrated “exploratory behavior.” Did they try out new gestures unprompted? And how quick were they in learning how to do all of these things, and do them well?
Cooley and Haworth are still analyzing all of the data from their studies, including the movement information captured on the lab’s motion-capture cameras. By the end, they hope to have a good profile of the kind of patient more likely to use a myoelectric limb. The findings can also help engineers design a better product.
After she graduates, Cooley’s planning on finishing physical therapy school, with an emphasis in prosthetics and orthotics (external aids, like ankle braces or shoe inserts). Beyond that, she’s interested in continuing to study the potential for technology to improve patients’ care.
“That’s where our world is moving towards, and it would be cool to integrate that more,” she said.
