The war in Iraq is not over, but one legacy is already here in this city and others across America: an epidemic of brain-damaged soldiers. Thousands of troops have been diagnosed with traumatic brain injury, or TBI. These blast-caused head injuries are so different from the ones doctors are used to seeing from falls and car crashes that treating them is as much faith as it is science. "I've been in the field for 20-plus years dealing with TBI. I have a very experienced staff. And they're saying to me, 'We're seeing things we've never seen before,'" said Sandy Schneider,...