Pioneering neural bypass allows chip in the brain to send signals to muscles in wrist and fingers, making it possible to swipe a card and play Guitar Hero
A 24-year-old man who was paralysed in an accident six years ago has regained some control of his hand using an implant that sends signals from his brain directly to the muscles that move his wrist and fingers.
Known as a neural bypass, the implant allows Ian Burkhart to swipe a credit card, play the video game, Guitar Hero, and perform actions such as picking up a bottle and pouring the contents, holding a phone to his ear, and stirring a cup. He is the first person to benefit from the technology.
Burkhart, from Dublin, Ohio, was on a beach holiday to celebrate the end of his first year in college when he dived into a wave that dumped him onto a hidden sandbar. He was 19, extremely independent, and had never considered that such an accident might strike him down.
The force of the impact snapped Burkhart’s neck at the C5 level. He could still move his arms to some extent, but his hands and legs were useless. Friends pulled him out of the water and raised the alarm. By chance, an off-duty fireman was on the beach and called paramedics.
Burkhart had therapy for the injury with a team of doctors at Ohio State University. From the start, he was hopeful that advances in medical technology would improve his quality of life. He told the team he was interested in research and willing to take part in trials of new technologies.
The Ohio researchers got their hands on a neural bypass developed by a charity called Battelle and offered Burkhart the chance to have the implant fitted. “That was the million dollar question: do you want to have brain surgery or something that may not benefit you. There are a lot of risks,” said Burkhart. “It was certainly something I had to consider for quite some time. But after a meeting with all the team and everyone involved, I knew I was in good hands.”
He went ahead and surgeons duly fitted a tiny computer chip into the motor cortex of his brain. Here, the chip picked up electrical signals from the part of the motor cortex that controls hand movements.
The fuzz of brain activity is fed into a computer and converted into electrical pulses that bypass the injured spinal cord and connect to a sleeve that Burkhart wears on his forearm. From there, 130 electrodes send the pulses through the skin to the muscles beneath, where they control wrist and even separate finger movements. The patterns of the signals are tuned to produce the movements Burkhart thinks about making.
It took time to learn how to use the device. Over 15 months, Burkhart spent up to three sessions a week learning how to control his hand movements.
“Initially we’d do a short session and I’d feel mentally fatigued and exhausted, like I’d been in a six or seven hour exam. For 19 years of my life I took it for granted: I think and my fingers move. But with more and more practise it became much easier. It’s second nature.”
“The first time I moved my hand, I had that flicker of hope knowing that this is something that’s working, I will be able to use my hand again. Right now, it’s only in a clinical setting, but with enough people working on it, and enough attention, it can be something I can use outside of the hospital, at my home and outside my home, and really improve the quality of my life,” he said.
Burkhart performed the first movements using thoughts alone in 2014, but has since learned more complex actions and more precise control over his hand and fingers. Details of the latest results are published in Nature.
“It was an amazing moment for the team,” said Ali Rezai, a neurosurgeon at Ohio State’s Wexner Medical Center, recalling Burkhart’s first hand movements. But at the time, his control allowed for only basic movements. “A few seconds after the amazement, we said OK, we have much more work to do here.” The team set to work on turning the rough movements into precise, useful actions.
Chad Bouton, who helped create the device, said the study marked the first time a person living with paralysis had regained movement using signals recorded from within the brain. “We think this is an important result as we try and pave the way for other patients in the future, not only those with spinal injuries, but also those that have experienced a stroke, and potentially even traumatic brain injury,” he said.
“We were not sure if this would be possible,” Bouton added. “Not only were we able to find those signals in the brain and decipher them for individual finger movements, but we were able to link those signals to Ian’s muscles and allow that kind of movement to be regained. This is important for daily activities, such as feeding, and having the patient be able to clothe themselves.”
The researchers are now looking at a host of improvements that should make the system more portable and possible to use outside the hospital. Brain signals picked up by the implant could potentially be sent wirelessly to the computer for processing, and onwards to the forearm sleeve to stimulate the muscles. Another improvement could see more electrodes added to the brain chip, so more subtle signals can be detected and passed on to the patient’s muscles.
“Ten years ago we couldn’t do this. Imagine what we can do in another 10,” said Rezai.
Nick Annetta, an electrical engineer on the team, said the team was working to make the system smaller and useful for a broader range of patients. “This could be applied to other motor impairments, not just spinal cord injuries,” he said. “We think this is just the beginning.”
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