video of a soccer player experiencing a head collision during a soccer game. Although she was lying on the ground afterwards, the referee did not stop the game.

Contrary to popular belief, concussion does not necessarily involve loss of consciousness, which is just one of many symptoms of concussion. Loss of consciousness frequently lasts only seconds to minutes, so it is often not even detected because of the delay in stopping a game and assessing the condition of a player following a head collision, said Dr. Hergenroeder. “A player will be down on the soccer field and the ref won’t stop play. A minute later you go out, and the player’s eyes are open, they are responding, so everything looks mild, but you don’t know if they lost consciousness,” he said. This is a problem since most grading systems use loss of consciousness to indicate a more severe concussion.

Another symptom of concussion is loss of memory (amnesia) and the presence of this symptom usually boosts a concussion from a low grade to an intermediate grade in most grading scales used, said Dr. Guiskiewicz. But in a large study he conducted of concussions in high school and collegiate football players, he found that only about one quarter of all their concussions were accompanied by the symptom of amnesia and only nine percent involved any loss of consciousness. “While I think these are two very important components or parameters to look at when we are evaluating concussion,” he said, “we can’t forget about all these other things that show up. We’re missing the boat if we just focus on these two parameters.”

Another symptom of concussion is headache. But this symptom can be problematic when diagnosing concussions because soccer and football players frequently report having headaches without experiencing head collisions, especially female athletes, pointed out Dr. Brooks. “The important thing to realize is that posttraumatic headache is difficult to differentiate from any of the other types of chronically recurring headaches players experience,” she said. For example, stress, dehydration, or fatigue can all cause headaches.

Dr. Kelly reported that other early signs and symptoms of concussion are a vacant stare and a slowness to answer questions or follow instruc

GRADES OF CONCUSSION

Although other guidelines have been established, these are the most widely used by concussion researchers. Note that these are guidelines, established by expert consensus. The studies necessary to establish the link between these or any other concussion grading schemes and the underlying mechanisms of brain injury have not been conducted.

Practice Parameter, Quality Standards Subcommittee, American Academy of Neurology 1997

tions, disorientation and muddled thinking, slurred or incoherent speech, stumbling and inability to walk in a straight line, balance problems, dizziness, and nausea and vomiting.

Some symptoms do not appear until days to weeks following a concussion, Dr. Kelly added. These symptoms include persistent headache, lightheadedness, diminished attention and concentration, poor memory, easy fatigability, irritability and anxiety and depressed mood, intolerance of bright lights or loud noises and difficulty focusing vision, and sleep disturbance.

Contrary to popular belief, concussion does not necessarily involve loss of consciousness, which is just one of many symptoms of concussion.

There are also more newly discovered subtle signs of a concussion that occur later and appear to be more persistent than the traditional symptoms. Two neuropsychologists, Drs. Barth and Echemendia, reported evidence at the workshop that brain functions are impaired even after the obvious symptoms of concussion disappear.

In two separate studies, they gave college freshmen athletes a battery of tests that measured a number of abilities including attention and concentration, memory, reaction time, problem solving, and verbal learning. They then conducted the same tests in those athletes that suffered concussions during the studies, at various time intervals following the concussions.

Both studies showed that these athletes tended to do the poorest on these tests at 24 or 48 hours following the concussion. Conducting



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