A group of European scientists announced this week that they’d successfully created a robotic arm that a patient can move and feel with his mind. Pierpaolo Petruzziello, a 26-year-old Italian living in Brazil, had electrodes temporarily implanted into his upper arm (he lost his forearm in a car accident) for a month and learned to make the unattached prosthesis wiggle its fingers, make a fist, and do other movements. Mastering use of the hand took only days, scientists said, and by the end of the experiment, the hand obeyed 95 percent of the time. "It felt almost the same as a real hand," Petruzziello said. Scientists say it will take a few years before the electrodes can be implanted for a longer period of time, but this was an important step in the development of thought-controlled prostheses.