The 1997 Practice Parameter of the American Academy of Neurology (AAN) for Concussion in Sports

Parameters:

(1) loss of consciousness (LOC)

(2) transient confusion

(3) duration of concussion symptoms (headache, dizziness, vertigo, nausea, vomiting, lack of awareness of surroundings) or mental status abnormalities

where:

• In the implementation I added a Grade 0 to handle the situation when transient confusion was absent.

• Brief loss of consciousness indicates seconds.

• Prolonged loss of consciousness indicates minutes.

• I am not sure if there is a special designation for a person with prolonged confusion but no loss of consciousness. It might be best to classify them as Grade 3.

The minimum period without postconcussive symptoms before return to competition allowed:

where:

• An athlete with a single Grade 1 concussion may return to competition the same day if the sideline assessments (including mental status examination) (a) at rest and (b) after exertion are normal.

• Any persistent Grade 2 symptoms (lasting > 1 hour) warrant medical observation with re-examination the next day.

• After multiple injuries the person should be asymptomatic at rest and with exercise for the minimum period given in the table.

• For multiple injuries, I set the grade to the maximum grade for current and previous injuries.

• The length of time before return to competition after multiple Grade 3 injuries depends on the clinical decision of the evaluating physician.

• The season should be terminated for an athlete with any abnormality on CT or MRI scan consistent with brain swelling, contusion or other intracranial lesion. If associated with a Grade 3 concussion, it may be appropriate to seriously discourage the player from returning to play in the future.