Paralyzed Man Controls Robotic Arm by Thought Alone

People paralyzed in accidents may be able to achieve great independence with a new robotic arm, according to a study published in PLOS ONE. Researchers were able to implant an electrode array on top of the brain of a 30-year-old paralyzed man that allowed him to control the movement of a character on a computer screen and move a robotic arm.

Tim Hemmes suffered a spinal cord injury seven years ago during a motorcycle accident that left him unable to move his body below the shoulders. Yet brain-computer interface (BCI) may allow him more independence. Researchers, including lead investigator Wei Wang, measured his brain waves as he watched videos of arm movement. They then used the information to place a postage stamp-sized electrocortigraphy (ECoG) grid of 28 recording electrodes on the surface of the brain region that controlled right arm and hand movement. Wires from the device were then led under the skin of Hemmes' neck to emerge from his chest. There, they could be connected to computer cables as needed.

It wasn't easy to learn how to move things with his mind, though. For 12 days at home and nine days in the lab, Hemmes trained to learn how to use the new device. He watched a virtual arm move, which triggered neural signals that were sensed by the electrodes. Different signal patterns were associated with particular observed movements, and were used to guide the up and down motion of a ball on a computer screen. After mastering this movement, Hemmes went on to use his brain to control the 3-dimensional movement of the ball, moving it in and out.

Eventually, scientists moved him onto the arm. He was about to high-five one of his friends for the first time in seven years, and was soon doing tasks by himself-all just by using his brain. This new technology could help those who have been paralyzed gain further independence, and could further lead to new prosthetic technologies.