Uchicago researchers recreate the sense of touch and motor control in paralyzed patients

Using virtual reality

“Manipulating the VR arm is very exciting because when I started doing it, I tended to try to move my own arm,” Imbrie said. “Now I’ve learned that just thinking about moving makes it work so much better. Sometimes when I’m learning to do a new task with the virtual arm and hand, I have to think about how I would move the actual hand and arm just to put them on my head, so I can imagine doing it with the virtual arm. Sometimes I lose control of the virtual arm, so I hum for myself or close my eyes and rethink how to do it. It’s exciting. There are a lot of different methods that I try to make things work when they don’t work so well. ”

During her four-hour test sessions, Imbrie performs activities that seem repetitive: with a VR headset slid over her eyes, she uses her mind to move a floating hand in a virtual reality environment. For this activity, he picks up a cup from a table, moves it to align it with a target presented by the system, and places it down again. Later, Imbrie will focus as the researchers feed the sensory information into her brain as she reports on where she feels and how she feels.

“There are 62 different channels that affect my sense of touch in a different place,” Imbrie explained. “I feel it on the surface in some places, or maybe deep, like under my fingernail. And there are also different differences in feelings, like for those I’m on the top of my finger, on the surface, it feels like a paper clip or a needle pushing on it. But this other one on the edge of my thumb, I feel like I’m reaching for perennials to clean the needles and they sting me. ”

Even a few months after her surgery, Imbrie has made rapid progress in the study.

“Scott can do several different tasks right now,” Downey said. “You can reach and place your hand in space, grab and move objects, and even grab objects with varying strength. He is also doing sensory tasks, which involve us stimulating his brain and informing us of how the sensations are, how strong they are, if they tingle or have pressures. We are using this to find out exactly how we can change the way we stimulate the brain to change the feeling Scott feels and try to make things feel like his hand is touching a natural object.

All of the data from these repeated tests is entered into modeling systems that the research team uses to fine-tune computer programs that translate Imbrie’s thoughts into motion and give her a sense of touch. The hope is to use this information to inform not only about future work with Imbrie, but also about future studies, and finally to develop technologies that can be widely and regularly used by paralyzed or missing members.

“All the sensory signals that come from the hand provide you with information about the objects you interact with and your interactions with them,” said Bensmaia, a professor of biology and anatomy at the James and Karen Frank family organism. “Our goal is to give the users of these robots the skill with which we are endowed with our own native hands. As for the motor, we want to understand how the brain naturally controls the hand. How can we speak the language of the brain and be able to recognize that language by moving that robotic hand? In terms of meaning, when we touch something, how does the nervous system respond to that? And how does this neural response result in a perceptual experience? “

While researchers hope to find additional tetraplegic subjects who may be interested in participating in this study, they acknowledge that not all candidates will have the same level of functionality as Imbrie. Imbrie has been the ideal candidate for this trial due to his pre-existing spinal cord injury, limited use and feeling of his hands, and willingness to devote time to study; is in the lab for 15 hours a week doing experiments.

Plus, he loves the job.

“Scott is a gift,” Bensmaia said. “He is someone with unbridled enthusiasm and he is so generous, so positive and so motivated. He came, they put these implants in his brain and the next day he said, “When can we start?” He just touched the ground and he’s great at everything. “

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