Present Prosthetics

25 year old Matthew Nagle, former football star became involved in a melee at the beach and he was stabbed. Doctors said that Nagle would most likely die. Luckily he survived and volunteered for an experimental trial to see if a human can effectively manipulate a computer cursor using a brain-computer interface. Surgically implanted beneath Nagle’s skull, is an array of electrodes. On a chip contiguous to the part of his brain that controls motor activity. The chip has 100 tiny hairs thin to pick up the electrical signals transmitted by the brain, each electrode picking up signals from a few nearby neurons. A square gray plug is screwed onto a pedestal, which is connected by wires to a nearby computer. When Nagle’s neurons fire the impulses are decoded by special software that can interpret the electrical pop of sets neurons, in other wise reading his mind. This software is used to decipher a few simple commands spoken in the electrical language. Nagle can sit in front of a prosthetic hand hooked up to a computer and it will open and closed to the thoughts of Nagle opening and closing his own hand. Nagle is the first human to control a prosthetic limb with his mind.

Scientist at a rehabilitation institute in Chicago describes a procedure to surgically implant nerves from the shoulder to the upper chest muscles of a woman who has lost her arm. The rerouted nerves then grew into the muscle which strengthens the messages sent to the muscle in the arm and hands; which are now read by the sensors of a prosthetic limb. The patient has developed a surprising degree of sensory perception, scientist say that will be the key in the next generation of prosthetics. Most artificial arms are controlled by remaining muscles in the arm but the devices can be frustrating and slow. The user must consciously contract the muscles for any movement at all, and only one movement can be performed at a time. Scientist have transplanted to the upper chest both motor and sensory nerves that would have traveled from the shoulder to the muscles in the arm and the hand in the months after the surgery the transplanted nerves grew into the chest muscle triggering twitches in the shoulder muscle when the patient thought about moving her arm or elbow. Within a few days afterwards the patient was able to use her new arm four times as fast on movement test as she would have been with traditional prosthetics. She said that the device was much easier to use, she could now move the elbow hand and wrist at the same time. We have come a long way in the engineering and mechanizing prosthetics over the last few centuries, but we still have a lot of room to improve on.