Doctors once believed that, whenever a blow to the head resulted in a brain injury, the victim would lose consciousness. Without a loss of consciousness, they would say, there could be no brain injury. That’s no longer the case. Now, medical professionals agree that a brain injury can result without the victim ever blacking out. Further, we now know that traumatic brain injury can result even without a blow to the head, such as in cases of "shaken baby syndrome" or, in adults, as a result of a whiplash-induced contrecoup injury.

An injury victim is considered to have suffered a Mild Traumatic Brain Injury (frequently referred to as a "concussion") if a trauma has caused a disruption of brain function as evidenced by any of the following:

  • A loss of consciousness, however brief; OR
  • Inability to recall events immediately before or after the accident; OR
  • Any alteration of mental state (for example, feelings of being dazed or confused) right after the accident.

A concussion can result in a long list of symptoms. The symptoms are sometimes called "post concussive syndrome" and can include:

  • pain,
  • fatigue,
  • sleep problems,
  • mood changes,
  • headaches,
  • inability to concentrate,
  • word finding difficulties and other cognitive problems,
  • memory problems,
  • frustration,
  • loss of sense of smell,
  • nausea,
  • dizziness,
  • visual problems,
  • ringing in the ears,
  • frequently becoming lost or confused,
  • feelings of depression.

The symptoms may not appear until days or weeks after an injury. Fortunately, most victims of mild traumatic brain injury completely recover from their symptoms within a year. However, a minority of victims — perhaps up to 15% — do not.  For some of those people, "mild " traumatic brain injury can lead to a lifetime of problems. The problems can be devastating.  For example, the victim’s inability to concentrate can result in his losing his job and mood changes can place great stress on family relationships.