A concussion is a type of traumatic brain injury that results in the temporary loss of normal brain function.

Concussions can be caused by a direct blow to the head, such as from falling, getting hit or being in an accident. They can also occur as a result of rapid acceleration-deceleration of the head, such as in whiplash injuries or blast injuries, like in a war zone. Many people assume that concussions involve passing out or a loss of consciousness, but this is not true. In many cases, people with a concussion never lose consciousness.

Most people will recover quickly and completely following a concussion. Some people can have symptoms that last for several weeks before gradually getting better. Some people, however, will require further treatment.