A 53-year-old woman paralyzed from the neck down by a genetic neurodegenerative condition has learned to manipulate a robotic arm with her thoughts , researchers report today in The Lancet. In the video above, she uses the arm to remove plastic cones stacked on a base and restack them one by one on another base. Surgeons had implanted two 4x4-millimeter grids of hair-thin electrodes in her brain to capture signals from regions involved in planning hand and arm movements. A computer translated those signals into commands to move the robotic arm, which has nearly the same movement capabilities as the real thing. Earlier this year, another research team reported that two tetraplegic patients had learned to grasp and manipulate objects  using a brain-machine interface (BMI), as these sophisticated prosthetics are often called. This new study improves on that work by demonstrating even more fluid and natural movements—the best yet performed by a paralyzed human patient using a BMI. It also allowed the patient, Jan Scheuermann, to fulfill a long-sought goal: feeding herself a piece of chocolate.
See more videos .