There's a lot of misunderstandings that we have found in the area of brain injuries and post concussions. The classic misunderstanding that people have is you have to be knocked out to get a concussion. That is simply not the case.
Another misunderstanding involves the Glasgow Coma Score. This is a test or an observation classically done by first time responders and then typically again at the emergency room. This test measures the injured person's awareness and responsiveness and they give you a grade, something like 3-8, 9-12, 13-15. 15 is the highest score and 3 is the lowest.
A lot of people are under the impression that if you have a normal Glasgow Coma Score, 15 at the scene, then you don't have a brain injury. This is not true. It is very common to have a mild Glasgow Coma Score, like a 13-15, and still have a significant brain injury because brain injuries don't always manifest themselves immediately at the scene. Typically, this Glasgow Coma Score is being taken by a paramedic or someone at the scene which means the score depends upon their training and ability to accurately determine what the person's status is and then it is taken again a little later, usually at the ER where the victim is usually more responsive.
It's important to remember that the Glasgow Coma Score isn't a measure of the injury, it's the measure of awareness and responsiveness. Keep this in mind. So, if someone has a normal Glasgow score or even a mild score, they may still have a very significant brain injury, particularly as it manifests itself days and weeks following the accident.