The Glasgow Coma Scale is easy to use for almost anyone to determine the state of a head injury. It includes eye, verbal and motor responses (see http://en.wikipedia.org/wiki/Glasgow_Coma_Scale).
But it should be clear that it should not be the only test used. This was a hard lesson for the medics that treated Natasha Richardson after her skiing head injury (2). For this reason when my daughter fell off a scooter and hurt her head, her doctor suggested I take her to the hospital for a scan.
1. Nowak TJ, Handford AG. Pathophysiology: Concepts and Applications for Health Professionals. New York: McGraw-Hill, 2004.
2. Tremblant M. 2009. 911 Calls Show Urgency of Richardson Fall. CBS News. Available at: http://www.cbsnews.com/stories/2009/03/31/entertainment/main4906004.shtml