A 24-year-old man who was paralyzed 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, OH, was on a beach holiday to celebrate the end of his first year in college when he dove 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 Memorial Institute (Columbus) 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.
A specially made sleeve on the forearm receives signals from a tiny chip in the motor cortex of the brain that enables hand movement. 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 practice it became much easier. It’s second nature.”
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.
Monday, April 18, 2016 / Vol. 24 / No. 15