Real world infoEdit
The following information was included in this article when it was initially created. As per policy, it has been removed because, obviously, this information pertains to the real world and is not anything that was stated in Star Trek. --From Andoria with Love 04:55, 9 April 2007 (UTC)
- Most victims of concussion recover completely, but serious blows to the head can cause internal bleeding or swelling, which require medical attention. Amnesia accompanies the mental disruption, so that the victim is unlikely to be able to remember the events immediately before and after the injury. However, the amnesia resulting from a concussion does not cause the loss of autobiographical information, which is why one should ask the victim questions to determine the extent of the amnesia; if the victim does not remember its name, he or she may be experiencing hysteria or another condition. 
- The humanoid head is constructed in a series of layers that serve to protect and support the brain, which has a very delicate consistency. The skull is a hard shell that encases the brain and protects it from normal movement. Inside the skull, a layer of cerebrospinal fluid cushions the brain. However, any sudden movement can cause the brain to strike the inside of the skull, which in severe cases can lead to internal bleeding.  The concussion results from the rotation of the brain hemispheres within the skull. It is unlikely that a concussion will result from a simple blow to the back of the head if there is no motion transferred to the brain. 
- A common sign of a concussion is a sign of trauma to the head, including a dent or fracture in the skull. There may or may not be bleeding, headache, dizziness, or vomiting. The victim does not always lose consciousness, but may exhibit dazed behavior, slured speech, or a lack of attentiveness, either immediately after the injury or later. Sometimes there will be changes to the victim's personality, such as irritability, or increased drowsiness and slurred speech. These symptoms may appear up to 24 hours after the injury and may last days or weeks afterward. 
- According to Dr. Handal, when a person sustains a blow to the head, it is best that someone who knows the victim to monitor the condition, since he or she will be able to notice the behavior changes, which may be slight. If the victim wishes to sleep, it is all right to allow it, but the victim should be awakened every 2 to 3 hours in order to gauge his or her awareness. Although a single concussion is not necessarily serious, repeated concussions are thought to cause more serious neurological damage.