By improving the technology in the arm and working more closely with test subject Jan Scheuermann, researchers have since enabled her to replace the simple pincer grip of before with four new hand shapes – fingers spread, pinch, scoop, and thumb up – that allow for more complicated object manipulation.

Back in February 2012, Schuermann had two electrode grids – with 96contact points each – surgically implanted into her left motor cortex, which controls right arm and hand movements. Hooked up to a brain-computer-interface, she was able to reach in and out, left and right, and up and down with the arm within a week of the surgery. In a few months she learned to flex the wrist back and forth, move it from side to side, and rotate it. She could also grip objects using a crab-like pincer hand shape.

For this second study, the researchers sought to increase the hand's functional utility while also maintaining a relatively low-complexity control space because more possible maneuvers means considerably more calibration. The 10-dimensional (10D) control (three dimensions of translation, three of orientation, four of hand shape) that they settled on had not been tested elsewhere, and they were unsure whether the brain would exhibit a preference for just one dimension or simultaneously handle all 10.