Concussion: Definition and Symptoms

A concussion is a velocity injury.  It happens when the brain hits the inside of the skull.  The brain, which is soft,  is surrounded by spinal fluid that cushions it from your skull, but when your head collides with something else, or when it is shaken severely, the brain impacts the skull and neurological changes occur.  A bull rider's head hits the bull's head.  A baby is shaken violently.  A driver is involved in a whiplash accident.  A soldier is close enough to an exploding mortar shell that the  force of the blast impacts his head, shaking it violently.  Any rapid acceleration/deceleration of the head can cause a concussion. 

There are a few different grading systems for concussion with anything from three to five grades.  In most of them grades one and two do not involve loss of consciousness.  I am not a doctor, and the following breakdown is not an official grading system, but it should give you a feeling for the kinds of criteria used in the various grading systems.

• No loss of consciousness.  Feeling confused, stunned, or dazed.  Symptoms lasting less than 15 minutes.

• No loss of consciousness.  Symptoms lasting longer than 15 minutes.

• Loss of consiousness (under five minutes).  All previous symptoms.  May include amnesia - no memory of just prior to the incident and/or just after the incident.

• Loss of consciousness over five minutes.  All of the previous symptoms.

Concussion symptoms may also include irritability, headache, dizziness, seizure, fatigue, anxiety.  Part of the continuing study of concussions seeks to understand how long symptoms may last.