Back in Touch: Technology Restores Hand Sensitivity to Young Quadraplegic
A sense of touch has been restored to a young man who lost it after being left paralyzed from the elbows down following a swimming accident nearly a decade ago.
How? By tapping into almost imperceptible neural signals that can remain even after spinal cord injury, and amplifying those signals to the point where a lost sense of touch can be regained.
The process was achieved through an innovative use of brain-computer interface (BCI) technology that aims to give paralyzed patients some measure of body control.
BCI "is a technology that records brain activity [and then] sends it to a computer to detect specific 'thoughts,'" explained study leader Patrick Ganzer. He's a principal neurotechnology research scientist with Battelle, a nonprofit science and technology company in Columbus, Ohio.
The computer then formats those thoughts into instructions, Ganzer said. Those instructions then get sent back to the patient, either directly to the patient's muscles or to a prosthetic device that triggers an action, such as hand movement.
Ocean diving left him with spinal cord injury
That's exactly what Columbus resident Ian Burkhart signed up for back in 2014, at the age of 22. Just three years earlier, while a freshmen in college, he had broken his neck while swimming in the ocean.
"I dove into a wave that pushed me into a sandbar," Burkhart recalled. "So essentially what I was diving into was just a few feet deep."
The diagnosis: "I am a C-5 quadriplegic with a complete spinal cord injury. I can move my shoulders, my biceps, and my hands around a little bit," he said. "But I don't have any control over my wrist or hands, or most of my abdominal muscles, or anything from the waist down. I can drive my wheelchair with a joystick, but I can't grip on that joystick. I can use an iPad by moving my whole arm around and using my knuckles, but I can't tap with a finger."
In 2014 Burkhart began working with Ganzer and his colleagues. First, he underwent invasive surgery to have a small computer chip implanted in the motor cortex region of his brain. "That way they can just insert a big plug into the top of my skull, and then plug me right into the computer," Burkhart said.
And after slipping a muscle stimulation sleeve (outfitted with a system of electrodes) over his arm, the team was able to successfully trigger hand movement. "And that was awesome," Burkhart said.
But there was still a problem, Ganzer explained.
"Unfortunately, the participant's hand is not only completely paralyzed, but it is also almost completely lacking sensation," he noted. "This a major problem, as the sense of touch is critical for appropriate movement control. The participant has trouble detecting general touch, and essentially cannot even feel small objects. Because of this lack of sensation, at times the participant's hand also feels foreign."
Getting creative to restore vibrations
"Originally the study was only designed for me to regain movement control," said Burkhart. "But we quickly realized that if you want full control you need to feel something, because I was relying on my vision to know if my hand was on an object, or how hard I could squeeze something. So when they had the idea to create a bi-directional system that could help me feel something, I was really excited."
To do that, said Burkhart, the research team had to get creative, fashioning a motor device that can deliver the sort of vibrations felt with cellphones and video game controllers. "And then they put that around my bicep, where I do have sensation," he said.
The result? "Whenever I move my hand and touch something, the motor vibrates around my arm and I can feel it," Burkhart said.
"His ability to detect touch was almost completely restored," Ganzer said. "When he uses the system in real time, his movements speed up, and he is able to manipulate and transfer objects faster."
Claudia Angeli is director of the Kentucky Spinal Cord Injury Research Center. "The innovation presented in this work is that they are decoding both motor and sensory signals," said Angeli, who wasn't involved with the study.
"By allowing enhancement or restoration of both," she added, "the BCI provides a more realistic control of hand function."
More work to be done to make system portable
But Angeli cautioned that the work to date is complex, invasive and "very preliminary."
Ganzer acknowledged as much. For one thing, the machinery is far too cumbersome to be portable, though he said his team "is currently working with our collaborators to develop a take-home BCI system. This would allow for the BCI to be used during activities of daily living outside of the laboratory."
That objective is on pause for the moment, while the team searches for additional funding. But Burkhart -- now 28 and set to graduate from college this spring with a degree in financial planning -- is on board for the long haul.
"We need to get this into the hands of other people like myself," he said. "But there are a lot of components that go into making this happen. Being able to use this outside the lab will require a lot of miniaturization. We need a smaller plug connected to my head, smaller recording equipment that's portable, like an iPad or something that I can put in my book bag and hang on my chair, rather than a table full of equipment like it is right now.
"But I know all of that is possible," Burkhart added. "It's definitely possible."
The findings were reported in the April 23 issue of the journal Cell.
There's more information about on spinal cord injury at the U.S. National Institute of Neurological Disorders and Stroke.
SOURCES: Ian Burkhart, BCI patient, Columbus, Ohio; Patrick Ganzer, Ph.D., principal neurotechnology research scientist, Battelle, Columbus, Ohio; Claudia Angeli, Ph.D. assistant professor, department of bioengineering, School of Engineering, and director, Kentucky Spinal Cord Injury Research Center, University of Louisville; April 23, 2020, Cell