Two people who are virtually paralyzed from the neck down have learned to manipulate a robotic arm with just their thoughts, using it to reach out and grab objects. One of them, a woman, was able to retrieve a bottle containing coffee and drink it from a straw — the first time she had served herself since her stroke 15 years earlier, scientists reported on Wednesday.Here's how they did it:
The two people in this study, a 58-year-old woman and a 66-year-old man, are quadriplegic, unable to use their limbs as a result of strokes years ago. Each had a tiny sensor about the size of a baby aspirin injected just below the skull, in an area of the motor cortex known to be active when people move their arms or hands. They learned to move a robotic arm, mounted at shoulder height on a dolly next to them, by watching the researchers move the arm and imagining they were actually controlling it.
The sensor — a chip of silicon with 96 pinprick electrodes connecting to a patch of neurons — transmitted those neurons’ firing patterns from this imaginary movement to a computer, through a wire. The computer recorded the patterns, then translated them into an electronic command: Move left, now down, now right. With a little training, the two participants took control of the arm. It was the first time the man had used a limb of any kind in three years, and the first time in 15 years for the woman. Both were able to move the robotic arm and hand skillfully enough to pick up foam objects.See for yourself:
“This paper reports an important advance by rigorously demonstrating in more than one participant that precise three-dimensional neural control of robot arms is not only possible, but also repeatable,” says Donoghue, who directs the Brown Institute for Brain Science.
“We’ve moved significantly closer to returning everyday functions, like serving yourself a sip of coffee, usually performed effortlessly by the arm and hand, for people who are unable to move their own limbs. We are also encouraged to see useful control more than five years after implant of the BrainGate array in one of our participants. This work is a critical step toward realizing the long-term goal of creating a neurotechnology that will restore movement, control, and independence to people with paralysis or limb loss.”Here's a link to the original Nature article, which gets really technical, but adds a lot of color and detail to the narrative.