Motor control

UChicago researchers recreate sense of touch and motor control in paralyzed patient

Newswise — On October 27, 2020, surgeons and researchers at the Medical University of Chicago performed a delicate surgery to implant specialized electrodes into the brain of a quadriplegic patient, allowing him to control, manipulate and sense sensation of an arm in a virtual reality environment. The subject is the first person in Chicago and only the fourth subject to participate in an ongoing multisite study dedicated to understanding how the brain receives and sends motor and sensory signals.

Scott Imbrie was 19 when a car accident damaged his spinal cord and left him paralyzed from the neck down. Although his doctors said it was unlikely, after months of rehabilitation he was able to learn to walk again. Now, decades later, he is once again pushing the boundaries of medical possibility – this time as the subject of a unique research trial to test the use of neuroprosthetic devices that allow him to sense and manipulate a virtual hand and possibly a robotic prosthesis.

Imbrie’s surgery was the first time the procedure, including both motor and sensory electrodes, had been performed in Chicago. The implanted electrodes receive neural signals from his motor cortex, allowing him to control and manipulate an arm in a virtual reality (VR) environment. They also send sensory feedback to his brain, allowing him to feel tactile sensations on his hand to “feel” pressure and vibration. Ultimately, the team plans to connect the system to a robotic prosthetic hand for Imbrie to use in the real world. Refining this research and developing new advanced neuroprosthetic devices would provide new freedom for people who are paralyzed or missing a limb.

The study is an expansion of currently researching conducted at the University of Pittsburgh and the University of Chicago Chicago in other paralyzed patients. Like something out of a sci-fi movie, the goal, the researchers say, is to develop technologies that can replace missing limbs or restore touch and movement for those who are paralyzed.

“The brains of paralyzed people can still generate the signals that would normally control movement, but the signal cannot go beyond the injury,” said project leader John Downey, PhD, a researcher at the University of Chicago. “We’re trying to figure out how to use that signal from the brain to allow them to control a prosthetic robotic arm and hand. And in addition to being able to control the arm and hand, we want to give them the ability to feel as if their own hand is touching an object when this prosthetic touches an object.

During his four-hour test sessions, Imbrie performs activities that feel repetitive – with a VR headset slipped over his eyes, he uses his mind to move a floating hand around in a simple virtual frame. For this activity, he practices picking up a cup from a table, moving it to align it with a target presented by the system, and setting it down. Later, Imbrie will focus as researchers feed his brain sensory information as he reports on where he feels the sensation and what it feels like.

“All of the sensory cues that come from the hand give you information about the objects you are interacting with and your interactions with them,” said Sliman Bensmaia, PhD, the James and Karen Frank family professor of biology and the anatomy of organisms. “On the motor side, we want to understand, how does the brain naturally control the hand? How can we speak the language of the brain and be able to recognize this language when we move this robotic hand? On the sensory side, when you touch something, how come the nervous system reacts to that? And how does this neural response give rise to a perceptual experience?

Later this year, the research team plans to configure Imbrie with more than just a VR headset – they’re working to integrate a state-of-the-art robotic hand with a robotic arm that he can manipulate using the same electrodes he uses. for the VR system. While the technology is far from ready to hit the market, researchers are excited about the work they’ve done with Imbrie so far.

“Although the work with Scott is still very early, there are so many potential applications for this research in the future,” said Nicholas G. Hatsopoulos, PhD, Professor of Biology of Organisms and of Anatomy and Neurology. “It could help us develop technology that allows those who are paralyzed or have lost limbs to do basic daily activities, like getting dressed or feeding themselves, working on a computer, and even getting up and walking around. help of an exoskeletal robot.”

The investigators hope to find other subjects with quadriplegia who might be interested in participating in this study, and emphasize that they are looking for candidates in a wide range of injury types and abilities.

Imbrie himself is eager to participate in the project as long as the electrodes are functional and he is able to help provide more data for research, even knowing that he is unlikely to directly benefit from the results of the study. . For him, it is more important that work can help others.

“When I was first injured I was a quadriplegic,” Imbrie said. “Over time, things came back. I still have limited abilities and everything. But I think of people who don’t have the ability to move or anything. And I know that one day this study will give someone the opportunity to use a limb in some form, whether it’s their own or a robotic limb. And it’s gonna be really cool.

For more information about this ongoing research trial and eligibility guidelines for interested applicants, please contact John Downey at [email protected].

###

About University of Chicago Medicine and Biological Sciences

The Medical University of Chicago, whose history dates back to 1927, is one of the nation’s leading academic healthcare systems. It brings together the missions of the University of Chicago Medical Center, the Pritzker School of Medicine and the Biological Sciences Division. Twelve winners of the Nobel Prize in Physiology or Medicine have been affiliated with the Medical University of Chicago. Its main Hyde Park campus is home to the Center for Care and Discovery, Bernard Mitchell Hospital, Comer Children’s Hospital and the Duchossois Center for Advanced Medicine. It also has outpatient facilities in Orland Park, South Loop and River East as well as affiliations and partnerships that create a regional network of care. UChicago Medicine offers a full range of specialty care services for adults and children at more than 40 institutes and centers, including an NCI-designated Comprehensive Cancer Center. Together with Harvey-based Ingalls Memorial, UChicago Medicine has 1,296 licensed beds, nearly 1,300 attending physicians, more than 2,800 nurses, and approximately 970 residents and fellows.

Visit the UChicago Medicine Health and Science News Blog at www.uchicagomedicine.org/forefront.

Twitter @UChicagoMed Facebook.com/UChicagoMed

Facebook.com/UChicagoMedComer