Researchers at Case Western Reserve University in Ohio have developed a brain implant that allowed a paralyzed man to bypass his spinal injury and move his arm and hand. According to Antonio Regalado of MIT’s Technology Review, the Utah Electrode Array comprises 96 silicon needles that record the electrical impulses of neurons inside the brain.
“Surgeons implanted two bunches of silicon electrodes called Utah arrays, into the volunteer’s motor cortex, the part of the brain where movements are planned. Wires from each array emerge from the skull through metal ports and connect to computers that interpret the signals,” Regalado explained.
“To complete the bridge of the man’s spinal cord injury, doctors then inserted more than 16 fine wires into the volunteer’s right arm and hand. Electrical impulses sent to those electrodes cause different muscles to contract, creating movement in the shoulder, elbow, and wrist, an approach known as functional electrical stimulation, or FES.”
John Donoghue, one of the leaders of BrainGate, a consortium that is developing brain-computer interfaces and includes the Case Western team, points out that the movement isn’t yet fluid or natural.
“But the fact that they got a person to control their own body, to stimulate muscles in a specific way to make them move, and do it from a small patch of brain, is incredible,” he said.
To be sure, Robert Kirsch, a biomedical engineer at Case Western, said the volunteer is able to accurately control a computer simulation of his wired-up arm using his brain signals. Nevertheless, moving the real arm under brain control has proved more challenging, especially with weak and atrophied muscle.
“The virtual setup is perfect, it does what he says, but the FES system has to use his chronically paralyzed arm.”
Commenting on the above-mentioned report, Rambus Fellow David G. Stork notes that the Utah Electrode Array is the latest in an ever-progressing series of demonstrations from research labs at the University of Washington, Brown University and elsewhere illustrating how brain interfaces can be made to work.
“Each step has involved systems with more and more electrodes (providing finer and more-accurate reading). Further, the purely medical problems of longer and longer-term implantation are slowly being solved. What was once science fiction is now science fact, though there remain numerous hurdles before systems like this could be used more broadly,” he added.