Summary of evidence-based guideline update

To update the 1997 American Academy of Neurology (AAN) practice parameter regarding sports concussion, focusing on 4 questions: 1) What factors increasedecrease concussion risk 2) What diagnostic tools identify those with concussion and those at increased risk for severeprolonged early impairments, neurologic catastrophe, or chronic neurobehavioral impairment 3) What clinical factors identify those at increased risk for severeprolonged early postconcussion impairments, neurologic catastrophe, recurrent concussions, or chronic neurobehavioral impairment 4) What interventions enhance recovery, reduce recurrent concussion risk, or diminish long-term sequelae The complete guideline on which this summary is based is available as an online data supplement to this article.