The severity of a concussion is determined by the length of time the symptoms persist and whether there is a loss of consciousness, explains WebMD. In a grade 1 concussion, symptoms persist for less than 15 minutes and there is no loss of consciousness. In a grade 2 concussion, symptoms last for more than 15 minutes and there is no loss of consciousness. Any loss of consciousness from a concussion, even briefly, qualifies as grade 3.
A concussion is a brain injury that results from a blunt blow to the head, according to WebMD. Such injuries can move the brain in the skull, cause bruising and disrupting brain function. Common symptoms of a concussion include slurred speech, headache, blurred vision, sensitivity to noise and ringing in the ears. Other possible symptoms include clumsiness, confusion, nausea, balance problems and memory loss.
For grade 1 and grade 2 concussions, medical attention is needed but not on an immediate basis. Normal activities should only resume after symptoms clear, states WebMD. For grade 2 concussions, this can take as long as a week. For a grade 3 concussion, medical attention is needed immediately. Doctors evaluate a person with a concussion to check memory and the ability to concentrate.