Researchers have developed a robotic arm that has enabled a paralyzed woman to drink a cup of coffee — by directly controlling it with her mind. The development has raised the question of whether this approach could perhaps restore some mobility to similarly affected people in the future.
The 58-year-old woman was one of two participants in the BrainGate 2 project who controlled a robotic arm with their thoughts.
Implants the size of baby aspirin tablets in the subjects’ brains let them control the robotic arms. The project is led by Brown University and includes researchers from the United States Department of Veterans Affairs, Massachusetts General Hospital, Harvard Medical School and the German Aerospace Center.
“Our device connects back from the brain to the outside world, which could be a computer, a robot on a table which could be a useful assistant, or to a prosthetic limb that would carry out limb-like functions driven by your brain,” John Donoghue, a professor of neuroscience and engineering at Brown University and one of the study’s senior authors, told TechNewsWorld.
How the System Works
An electrode array is placed in the brain’s motor cortex, which governs the motion of the limbs. Specifically, it’s placed in the hand/arm area of the motor cortex. It reads the pattern of activity among nearby brain cells and feeds those signals to a computer that then uses these signals to move the robotic arm.
“The spatial and temporal pattern of activity across many neurons in [the hand/arm] area normally determines the direction and amplitude of arm movement,” Scott Currie, associate professor of neuroscience at the University of California at Riverside, told TechNewsWorld. This pattern of activity, called a “neuronal population vector,” is generated if a person even imagines the arm movement.
The subject, Cathy Hutchinson, used the robotic arm to grab a flask of coffee on a nearby table, lift it and hold it to her lips. She was paralyzed and left unable to speak by a stroke nearly 15 years ago.
Hutchinson used a robotic arm attached to computers that process the information sent from her brain. These computers are currently about the size of a minifridge but could be shrunk down over time to something “the size of a smartphone,” Brown University’s Donoghue said. A prosthetic limb that will be usable in real life is about 10 to 15 years away, he suggested.
It’s a Long, Hard Road
The signals sent by the implant in the woman’s brain to the robotic arm may have enabled her to raise a flask to her mouth, but much more work will need to be done before the system is fit for common use, Lee Miller, the Edgar C. Stuntz distinguished professor of neuroscience at Northwestern University, told TechNewsWorld.
“There’s no question [BrainGate2] is an impressive development, but if you look at the quality of those movements, it’s not really something that’s functionally useful at this point,” Miller remarked. “Clearly it’s early stage.”
Miller led a study at Northwestern in which monkeys were used as test subjects for brain electrode implants.
Fit the Solution to the Problem
BrainGate2 “is certainly a very promising direction for neuroprosthetics research, but it’s one of many, so I wouldn’t call it the future of prosthetics,” UC Riverside’s Currie said.
BrainGate2 is being used for people who had a stroke, Northwestern University’s Miller said. It might not be suitable for amputees or people with cervical spine issues.
For example, Todd Kuiken and Gregory Dumanian of NorthWestern University have pioneered targeted reinnervation, Miller pointed out. Here, the nerves of a targeted muscle are cut or deactivated and replaced by the remaining nerves of an amputated limb to drive a prosthetic device.