back to the wall" which offers help to ptsd patients and afghan war veteran and military medic nick colgan, he also suffered a traumatic brain injury on the battlefield himself. welcome, gentlemen. nick, let me start with you. you suffered tbi. what does that involve exactly? how did you experience yours and what are soldiers going through in this situation? >> i was a medic with the 82nd airborne based out of ft. bragg, north carolina. i deployed to afghanistan for 15 months. on a deployment i did a lot of good, helped save a friend shot in the head and my unit was responsible for the rescuing of 42 afghanis from a flooding river but at the same time a rocket propelled grenade hit off my humvee and forever changed my life. i have a traumatic brain injury among other transition issues. >> were you knocked out? >> i remember it was like white for aonext day i woke up and didn't feel the same inside. i had an eye twitch and i just didn't feel similar and a lot of my battle buddies picked up on it. >> how long ago was that? >> 2008, and it's 2012 now and i'm still fighting through it every da