March 7, 2013 8:48 am App Studies User's Cognitive Response After Playing Contact Sports Doctors hope a new app will help prevent brain injury in athletes, specifically in girls who play soccer and use their heads to pass the ball. Rachel McNeill reports. US & World Videos 0:59 Runaway zebras corralled in Washington state; one still missing 1:40 Charlie Puth reacts to Taylor Swift's ‘The Tortured Poets Department' name-drop 2:52 Severe weather kills at least 5 as tornadoes rip through Midwest and South 0:48 World Central Kitchen to resume operations in Gaza 8:39 Gina Rodriguez gushes 0ver motherhood with son Charlie