In a paralyzing spinal cord injury, the biological wiring that connects our controlling brain to our useful limbs is cut off, resulting in permanent loss of sensation and control and usually a lifetime of additional health care. Researchers have spent years restoring those lost connections, allowing paralyzed patients to drink coffee and enjoy a beer with robotic limbs controlled only by their minds.
Now researchers have gone a step further, allowing a paralyzed person to control their own hand using only their mind.
This is according to a study published Wednesday in Nature, researchers report using a “neural bypass” that reconnects a patient’s mental commands for movement to responsive muscles in his limbs, creating a kind of synthetic nervous system. The pioneering patient, Ian Burkhart, a 24-year-old man who became quadriplegic after a diving accident nearly six years ago, can move his hand again. In the pilot study, he could control the movement of individual fingers, grasp objects large and small, use a credit card, and play Guitar Hero. The advance could open the door to restorative treatments for paralyzed individuals, enabling them to move and live independently.
These complex forms of movement “can really translate into a lot of functional, day-to-day tasks that I can’t do on my own right now,” Burkhart said at a news conference. “So that’s something that if and when I can use this system outside of the clinical setting, it will really increase my quality of life and my independence, and reduce the amount of help I need from other people.”
The neural bypass works using an array of microelectrodes implanted in Burkhart’s brain. The implant picks up activity in a specific area of his left motor cortex, which researchers had analyzed before placing the implant. Using functional magnetic resonance imaging (fMRI), which tracks brain activity based on blood flow, the researchers measured the hand-controlling area of Burkhart’s brain as he repeatedly thought about moving his hand.
At the clinic, the implanted electrode hooks into a custom-made “neural bypass system.” The system picks up on the signals from Burkhart’s brain activity and then translates those signals using machine learning algorithms to control a flexible arm sleeve equipped with 130 muscle-stimulating electrodes.
To get it to work, Burkhart attended three weekly sessions over 15 months. He mastered controlling his thoughts and could perform six hand and wrist movements, including the ability to move individual fingers.
The Nerve Bypass: How to Move a Paralyzed Hand.
Credit: nature video
“The ability to move individual fingers — we weren’t sure this would be possible,” said first author Chad Bouton of the Feinstein Institute for Medical Research. “This result really exceeded our expectations because not only were we able to find those signals in the brain and decipher those signals for that individual finger movement, but we were also able to link those signals to Ian’s muscles and produce that kind of movement. let it regain.”
After that, Burkhart learned more complex tasks, such as playing Guitar Hero and put a cup to his mouth.
“This technology has evolved rapidly over the past decade,” notes co-author Ali Rezai of Ohio State University. “It may be coming of age right now,” he said.
While the study is a landmark one, the authors say, researchers must continue to work on the system to refine it, adapt it to other types of paralysis patients and, perhaps most importantly, make it work outside of a clinical setting.
Despite the work ahead, Burkhart says he is and has been very optimistic about the investigation. When he first moved his hand after his accident a few years ago, he realized it could happen sooner than he expected. “And now, within two years since then, things are going even better than I imagined,” he said.
Nature2015. DOI: 10.1038/nature17435 (About DOIs).