At Case Western Reserve University scientists have given a quadriplegic man the ability to move his right arm and hand for the first time in years. To make this possible, two 96-channel electrode arrays were implanted to read and interpret signals produced by the motor cortex of his brain. A functional electrical stimulation system that involves electrodes placed at the muscles responsible for arm and hand motion, was interfaced with the brain implant via a computer.
As the patient thought to move his hand, the brain-computer interface analyzed and interpreted the related signals, passing on the intended movements in a form that the the muscle stimulator can turn into physical motion. This allowed the patient to perform feats such as to eat on his own and to scratch an itch exactly where he wanted to scratch it.
All this required not only hard work from the scientists, but a lot of practice and cooperation from the study subject. He first had to learn how to move a graphical arm, representing his own, on a computer screen. Though he was able to do so almost immediately, being able to move it with precision took a few months of practice. Once ready, the muscle stimulators consisting of 36 electrodes were implanted strategically next to the muscles to be activated. Following this, another period of adjustment was necessary because he has been disabled for eight years prior to this study, which meant the target muscles required physical therapy to overcome the atrophy. Eventually, after getting those muscles in shape and adjusting the system to match his capabilities, the man developed a level of dexterity that allows him to do basic things on his own.
Here’s a Case Western video with the patient and researchers who made this technology possible: