Brain injuries have come to the forefront since actress Natasha Richardson died following a skiing accident. Concussions are one of the most common injuries seen in emergency rooms across the country, but hundreds of thousands of people hit their heads every year and are never seen by a doctor. Dr. Jeff Bazarian, an associate professor of emergency medicine, neurology and neurosurgery at the University of Rochester in Rochester, New York, joins host Dr. Shira Johnson to discuss a blood test that could diagnose a brain injury without a CT scan.