Treating concussions in athletes should be done on a case-by-case basis.
That's the new primary recommendation from the American Academy of Neurology, which says athletes need to be treated according to their individual conditions, not a predetermined approach.
The guidelines do recommend, however, that any athlete suspected of having a concussion should be immediately removed from play.
"If in doubt, sit it out," Jeffrey S. Kutcher, a doctor at the University of Michigan Medical School, told the New York Times. "You only get one brain; treat it well."
The new guidelines brings the group in line with practices followed by the National Football League and other leagues and associations, which acknowledge concussions are too variable to fall into any generalized categories.
"We've moved away from the concussion grading systems we first established in 1997 and are now recommending concussion and return to play be assessed in each athlete individually," said Christopher C. Giza, a doctor at the David Geffen School of Medicine and Mattel Children's Hospital at the University of California Los Angeles and one of the lead authors for the new guidelines.
"There is no set timeline for safe return to play," he said.
The revised recommendations, unveiled at the academy's annual meeting in San Diego earlier this week, have been published in Neurology, the medical journal of the academy.
The study noted more than a million American athletes experience concussions each year, with the greatest risk in football and rugby, followed by hockey and soccer. Concussion risk is greatest for young women and girls in soccer and basketball.
The authors of the study said they didn't find any "clear evidence that one type of football helmet can better protect against concussion over another kind of helmet."
According to the new guidelines, signs and symptoms of a concussion include: headaches, sensitivity to light and sound, changes in reaction time, balance and coordination, changes in memory, judgment, speech and sleep, and loss of consciousness or blackouts.