BRAINS WITH MACHINES

A paralyzed man can now use a computer to move his arm

Ian Burkhart relished his independence as much as any other college freshman. But after a diving accident on a beach vacation with friends, he lost his ability to take care of himself at even a basic level. Burkhart broke his neck and damaged his spinal cord in a way that left him with limited mobility in his shoulders, and unable to move his hands and lower extremities. He was 19.

But now, almost six years later, Burkhart has regained at least some of the ability to move his hands, thanks to a breakthrough developed by researchers at Battelle, a non-profit research and development company based in Columbus, Ohio. A paper published in Nature today (April 13), explains how the team was able to equip Burkhart with a brain-computer interface and electrical cuff to translate Burkhart’s thoughts into movement of his hands and fingers.

This is the first time that decoded signals from the brain have been linked to muscle activation in real time in a human,” Chad Bouton, an engineer formerly with Battelle now at the Feinstein Institute and lead author of the paper, said. “The patient was able to not only regain movement in his hand, but actually perform functional tasks that would be useful in daily activities.”

Researchers say that Burkhart can now do things like pick up a glass and use his fingers to stir liquid in it. Though so far he’s only been able to do these things in a hospital setting, researchers hope that eventually he’ll be able to carry out some of these tasks at home, which could help him regain some independence in the form of feeding and dressing himself.

Surgeons implanted a tiny electrical array onto Burkhart’s motor cortex, which includes the part of the brain that controls hand movement. Burkhart then watched footage of various hand movements on a computer screen. Simultaneously, a computer connected to the electrode in Burkhart’s brain recorded the different patterns of neural activity. Once the computer began to recognize which patterns indicated different kinds of movement, it translated them into electrical impulses delivered through two cuffs wrapped around Burkhart’s forearm. These cuffs delivered electrical signals to Burkhart’s muscles, similar to the ones nerves deliver to muscles in healthy patients, which allowed him to control his own movements.

Essentially, this technology is mimicking the role of the spinal cord, Bouton said.

Brain-computer interfaces have been used in the past in conjunction with robotic prosthetics, but this is the first published instance of a patient being able to use his own limb with this degree of dexterity. The research team hopes that this work will be used to restore independence not only in patients who have suffered spinal cord injuries, but also stroke or neurodegenerative diseases, like ALS.

The technology is not perfect, though: Even though Burkhart can see his hands move an object in front of him, he can’t feel them. Being able to feel an object greatly improves your ability to handle it. Additionally, the patterns of neural activity change with Burkhart’s intentions. Sometimes, therefore, the computer wasn’t able to recognize all these movements, and Burkhart dropped the objects he was holding.

“We’re in the early stages of that development, but I hope that in the next five to ten years we’ll start to see forms of this technology become available,” Bouton said.

Correction: this article has been updated to show Bouton’s former affiliation, where the majority of the research was conducted.

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