YouTube videos yield clues to brain inju...(sburgh Steeler Ryan Clark in a Jan. 18 A...),Health

Moderate-to-severe head trauma can cause permanent brain damage or death if ignored by medical staff. Unfortunately, sometimes these injuries are not readily apparent. The fencing response provides an immediate visual cue that could help injured players get the attention they need, Lifshitz said.

"The observation of the fencing response can help coaches and trainers make immediate and future return-to-play decisions," Lifshitz said. "But the response is not universal. The absence of a fencing response should not be taken as a sign that no injury has occurred."

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