to the editor: I enjoyed reading Dr. Kushner's comprehensive review of sports-related concussions in American Family Physician.¹ As mentioned in the article, the risks of cumulative neurologic injury and fatal cerebral edema following repeated concussions have led to the promulgation of at least 14 management guidelines since 1973 to reduce these risks.² Several points regarding the validity and utility of the current guidelines deserve mention.

The published guidelines rely heavily on expert opinion and anecdotal case reports. Therefore, the guidelines differ in the criteria used to define mild, moderate, and severe degrees (or grades) of concussion. For example, as illustrated in Tables 1 and 2 of the article,¹ the guidelines of the Colorado Medical Society and the American Academy of Neurology (AAN) emphasize loss of consciousness more than any other sign or symptom of concussion in determining the severity of injury. These two guidelines assume that loss of consciousness (even for a period of seconds) portends a worse prognosis than a prolonged period of posttraumatic amnesia. In contrast, the guidelines presented in those tables¹ by Dr. Cantu³ consider prolonged post-traumatic amnesia (more than 30 minutes) as significant as brief loss of consciousness (less than five minutes) in determining the severity of a concussion. Currently, no compelling clinical data favor any single symptom or sign as a better predictor of severity of injury.⁴

All concussion guidelines agree that an athlete should not return to play if still symptomatic from a previous concussion. Returning an athlete prematurely to sport presumably exposes the athlete to the threat of second-impact syndrome and cumulative brain injury. However, the guidelines differ in their recommendations for returning players to competition once they are asymptomatic. For example, under the Colorado guidelines, an athlete who is completely asymptomatic following several seconds of loss of consciousness would immediately be transported to the hospital and kept from play until asymptomatic for two weeks (grade 3 concussion). Under the AAN guidelines, this same athlete may return to play after being asymptomatic for one week (grade 3, brief loss of consciousness). The Cantu³ guidelines return this athlete to play after two weeks, if asymptomatic for one week (grade 2 concussion).

Questions remain regarding the universal applicability of the current concussion management guidelines. In the published cases of the second-impact syndrome, all victims have been adolescents.⁵ This implies some age-related differences in vulnerability and response to brain injury. Nor do the return-to-play guidelines consider the different inherent risks of further head trauma among sports.

Concussion management guidelines have undoubtedly increased awareness of the signs, symptoms, and potential sequelae of concussion; however, more definitive, evidence-based information is needed to validate current recommendations. Newer diagnostic tools, such as neuropsychologic testing, may offer more sensitive means of determining the presence and severity of cerebral concussion.⁶ Ideally, optimum management of the head-injured athlete will occur through a synthesis of scientifically based guidelines and the physician's clinical judgment.