Thanks to a brain implant, Ian Burkhart can use his hand to play video games for the first time since the accident that broke his neck six years ago. The finding, published today in Nature, is the first instance of a person living with paralysis regaining the ability to move simply by thinking.
Burkhart was 18 years old when he dove into unexpectedly shallow waters while vacationing with friends. The impact severely damaged his spinal cord and left him paralyzed from the chest down. But a chip placed in the left side of his brain now lets the 24-year-old relay signals from his brain down to his right arm. The technology, which isn’t yet available to other patients, has allowed Burkhart to grasp cups and even move his fingers independently from each other to play a game that resembles Guitar Hero. Because of Burkhart’s success, the researchers think the technology might one day help people who are quadriplegic regain some autonomy.
"I know firsthand what was taken away from me after my injury."
"I know firsthand what was taken away from me after my injury," Burkhart told reporters during a press conference yesterday. So "the first time when I was able to open and close my hand, it really gave me that sense of hope for the future."
About 5.6 million people in the US have some form of paralysis. This means that about 1 out of every 50 Americans has trouble moving their arms or legs, which can make living independently difficult. In Burkhart’s case, the injury to his spine left him unable to walk and move his arm below the bicep. From a neurological standpoint, this means that when he tries to move a finger, the signals that his brain sends down to his hand are blocked. For researchers who study paralysis, that disconnect is hard to fix. That's why some scientists think it might actually be easier to reroute those signals and bypass paralyzing injuries altogether. Now, scientists have done just that — using an implant the size of a pencil eraser.
The system that allows Burkhart to move his fingers consists of three main parts: the tiny brain chip, a computer, and a sleeve full of electrodes placed on his forearm. When Burkhart thinks of a hand motion, the implant detects the signals in his brain and send them to a computer. Then, the computer deciphers them and relays the information to the sleeve wrapped around his right arm. From there, the sleeve uses electrical impulses to trigger muscle contractions that allow Burkhart to accomplish the hand movement he’s thinking of. So, in a way, the computer acts like a translator that relays information from the brain to Burkhart’s muscles.
Perfecting the technology was a years-long process that started even before Burkhart received the implant. In the very first stages, three years ago, the researchers spent a lot of time imaging Burkhart’s brain as he visualized performing hand motions that the researchers projected on a screen. During these sessions, the scientists recorded his brain signals and tried to match them to corresponding hand motions. In April 2014, Burkhart underwent a three-hour long surgery to place the implant in his brain. Two months later, he moved his fingers for the first time, although at the time, the movements didn’t help him to do much. Now, Burkhart can pick up a phone and hold spoon in his hand. To practice moving his fingers, Burkhart plays Frets on Fire, a video game that resembles Guitar Hero but that has been modified for one-handed play.
"It’s the first time this has been done and it’s a very big step forward in this field."
"He's not only picking up objects, but he's manipulating the objects. He can switch between a power grasp such as picking up a glass and then he can switch to a fine pinch grasp to pick up a small object such as a stir stick, and actually manipulate that and a few finer motor skills," says Chad Bouton, a neuroscientist at the Feinstein Institute for Medical Research who co-authored the study (the technology was invented at Batelle Memorial Institute, Bouton’s previous employer). "This is a first; it’s the first time this has been done and it’s a very big step forward in this field."
Even though Burkhart can perform some complex tasks, he still can’t spread his fingers to type on a keyboard, for instance, and he has very little control over the force that his fingers currently apply on a given object. That’s because the chip in his brain only contains 96 electrodes, which isn’t enough to translate precise hand movements. To fix that, the researchers want to increase the number of electrodes to a couple thousand. They would also like to compress the computer to make it fit entirely inside the implant and get rid of the wires by using wireless technology. If they can do all that, people living with paralysis might actually be able to use the system on the go, Bouton says. And it might be possible to use the technology to help people regain some motion in their legs as well.
"We think it can stay in the brain for five years."
That said, the system is still experimental. Bouton declined to tell The Verge how much the current system costs, but it’s pretty clear that improving it isn’t going to come cheap. There’s also some questions surrounding how long the implant might be able to remain inside the brain without being rejected. "To be honest there just haven’t been enough people that have had it in [their brain] to know how long truly this will last," says Nick Anetta, an engineer at Battelle Memorial Institute and another study co-author. "But we think it can stay in the brain for five years."
Because of this, the system probably won’t be ready for use outside the lab any time soon. But that doesn’t mean Burkhart is going to be first and last person to use the implant; a second patient is scheduled to being the study this summer the researchers say.
"Right now, it’s just in the clinical setting, but with enough people working on this and with enough attention, it’s something that I will be able to use at my home," Burkhart said. "This is something that’s working; I will be able to use my hand again."
Video by Miriam Nielsen.