NEW YORK (AP) -- When athletes are suspected of having a concussion, they should be taken out of action immediately, new guidelines from a major medical group say.

The American Academy of Neurology said athletes shouldn't resume playing until they've been fully evaluated and cleared by a doctor or other professional with concussion expertise.

The recommendations issued Monday generally agree with a brief position paper the academy issued in 2010, but add details on evaluation and management. The guidelines are based on a comprehensive review of scientific research.

Sports concussions have gained a new public focus in recent years because of concern over the risk of developing long-term mental impairment. Thousands of former pro football players are suing the NFL and its teams, saying that for years the NFL did not do enough to protect players from concussions.

The new advice replaces guidelines published 15 years ago. Those recommended grading the severity of concussions at the time of injury to determine possible time frames for return to play. Now the group emphasizes more individualized assessment and management of the injury.

Research showed the grading system didn't relate to outcome, and that nobody can predict how long recovery will take, explained Dr. Christopher Giza of the University of California, Los Angeles, an author of the new guidelines.

The new document says athletes should not be allowed back in action if they show any symptoms. And it says athletes of high school age or younger with a diagnosed concussion should be managed more conservatively than older athletes when it comes to allowing a return to play.

Dr. David Dodick, a concussion expert at the Mayo Clinic in Phoenix who was familiar with highlights of the new document, said they contain "no great revelations" beyond what experts know already. He noted that the guidelines state that the first 10 days after a concussion are the period of highest risk for being diagnosed with a second concussion, and that younger athletes take longer to recover from the injury.

Since getting a second concussion before the first is healed can lead to a long period of disabling symptoms, that is good guidance for doctors who have to decide when young athletes can return to play, he said in a telephone interview.

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