US Army combat medic Shawn Aiken puts on a transcutaneous electrical nerve stimulation (TENS) device to relieve his back pain at his home in El Paso, Texas May 20, 2013. Aiken, who served 16 months in Iraq and 13 months in Afghanistan and has been active duty for nearly 10 years, has severe post-traumatic stress disorder. He was injured by an RPG in 2010, which left him with a crushed left hip and a traumatic brain injury. Picture taken May 20, 2013.[Photo/Agencies]