Body
When someone incurs a spinal cord injury, the signals sent from their cerebral cortex to their limbs are reduced or interrupted, resulting in partial or complete paralysis. It’s hard for physicians and therapists to get those lines of neurological communication open again. But what if there was another pathway that could reach a person’s muscles and tell them how to move and what to do?
That’s what Dalia De Santis, PhD, a research scientist in the Shirley Ryan AbilityLab’s Center for Neuroplasticity, is working on. The cerebral cortex is the center of higher reasoning and voluntary movement in the brain, and it developed recently in evolutionary terms. But the brainstem, which sits at the back of the skull on top of the spinal cord, is a much older control center that regulates things like breathing and blood pressure. It also has a role in movement. When someone is startled and jumps, it’s a signal from a specific part of the brain stem that causes the reaction. “The brain stem has a lot of relays. We’re hoping it can be harnessed to take over some of the functions from the cortex after spinal cord injury,” says De Santis, 39.
Experimenting with a human’s brain stem is tricky because it is difficult to access noninvasively, and it controls so many critical functions. De Santis believes using loud clicks to engage it may improve a person’s ability to move when combined with traditional physical therapy. Under a 2024 grant from the National Institutes of Health, she ran a small trial to see if auditory stimulation during walking affected the locomotion of people with and without an incomplete spinal cord injury. She found that it did, but the sounds affected movement differently depending on where someone was in their stride. She also found that people with SCI had a reduced response to the sounds.
De Santis’s work may sound a lot like neurology but she is a biomedical engineer, not a medical doctor. Her career path was a surprise to her family in Modena, Italy, because many of her relatives were physicians, including her dad. Despite pressure to follow in her father’s footsteps, De Santis resisted. “I hate needles,” she says laughing. She studied humanities in college and did not take a lot of math classes. When she heard about a new program in biomedical engineering in Milan, it appealed to her but she wasn’t sure she could pass the entry exam, at least not on her first try. She did.
De Santis spent the next eight years getting a master’s in biomedical engineering in Milan and a PhD in rehabilitation robotics in Genoa. Then she heard about a post-doctoral position in Chicago with Ferdinando Mussa-Ivaldi, PhD, an Italian-American scientist at Northwestern University she really admired. Mussa-Ivaldi’s work focused on applying the biological and computational mechanisms of human learning to developing new tools for rehabilitation after stroke or spinal cord injury. She got the post and spent two years working with him on how to use wearable sensors to help people with severe SCI control devices like a computer, motorized wheelchair or a robotic arm.
In 2018, De Santis won a three-year Marie Curie Actions grant, which was established by the European Commission to support the training and career development of researchers across Europe. Splitting her time between Chicago and Genoa, she took what she had learned about wearable sensors and applied it in Italy to wearable robotic devices for upper limbs. De Santis was in Italy when the Covid pandemic hit in 2020, preventing her from having her planned summer wedding in Italy and returning to Chicago.
In addition to her fiancé, De Santis had another reason for wanting to return to Chicago. She had collaborated with Monica Perez, PhD, a researcher in Miami, during her time with Mussa-Ivaldi, and the two of them wanted to work together. In a fortuitous development, Perez had taken a job at Shirley Ryan AbilityLab in Chicago while De Santis was in Italy.
De Santis got married, made it back to Chicago in 2021, and embarked on a second post-doc with Perez, an international expert in spinal cord injury research. In 2024, De Santis was hired as a full-time research scientist at the Shirley Ryan AbilityLab and has been working on her NIH grant and other projects since then. “My dad always says ‘You left by the door and entered through the window’” she laughs. “I’m not a doctor but I ended up in a hospital anyway.”