Grading the concussion is a helpful tool in the management of the injury (see Cantu Guidelines below) and depends on:
1) Presence or absence of loss of consciousness
2) Duration of loss of consciousness
3) Duration of posttraumatic memory loss
4) Persistence of symptoms, including headache, dizziness, lack of concentration, etc.
Some team physicians and trainers evaluate an athlete's mental status by using a five-minute series of questions and physical exercises known as the Standardized Assessment of Concussion (SAC). This method, however, may not be comprehensive enough to pick up subtle changes.
According to the Cantu Guidelines, Grade I concussions are not associated with loss of consciousness, and posttraumatic amnesia is absent or is less than 30 minutes in duration. Athletes may return to play if no symptoms are present for one week.
Players who sustain a Grade II concussion lose consciousness for less than five minutes or exhibit posttraumatic amnesia between 30 minutes and 24 hours in duration. They may also return to play after one week of being asymptomatic.
Grade III concussions involve posttraumatic amnesia for more than 24 hours or unconsciousness for more than five minutes. Players who sustain this grade of brain injury should be sidelined for at least one month, after which they can return to play if they are asymptomatic for one week.
Following repeated concussions, a player should be sidelined for longer periods of time and possibly not allowed to play for the remainder of the season.