Guidelines for managing concussion in sports: a persistent headache.

In their approach to managing athletes who sustain concussions, sports physicians differ at least as widely as do the many published guidelines on the subject. The scarcity of scientific evidence makes practical decisions about when an athlete can safely return to the field difficult. Efforts to forge a consensus are underway, but controversy persists around such questions as whether a brief loss of consciousness should be classified as a severe concussion.