The system, developed byJennifer Collinger at the University of Pittsburgh, Pennsylvania, and colleagues, uses two small electrode grids implanted in Scheuermann's brain, in the region of the left motor cortex responsible for controlling her right arm and hand. The devices were connected to a computer, which analysed electrical brain activity picked up by 96 contact points within the grids.
Computer algorithms learned to match the electrical patterns to Scheuermann's thoughts about making specific movements with a hand or arm. These patterns were then translated into the real movements of a robotic arm.
The latest version of the algorithm can detect four patterns of activity related to the shape of the hand, adding a scooping shape, thumb extension and a pinching action to the repertoire of possible movements. The improvements allow Scheuermann to control the artificial limb with 10 degrees of freedom simultaneously.
