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Gillis, David


Nearly seven years after the AAN released guidelines on the management of sports-related concussion, the National Collegiate Athletic Association has taken serious stock of its own policies and practices on the football field by sponsoring two new studies on recovery from injury.

One study, which examined acute effects of recovery times following concussion, concluded that collegiate football players who suffered concussion should be free of symptoms for at least seven days before returning to action (JAMA 2003;290:2556–2563). The second study, which examined the cumulative effects of concussion, reported that football players with a history of concussion were more likely to suffer another injury than those who never had one. In addition, players with a history of concussion recovered neurological function more slowly than those who experienced their first concussion (JAMA 2003;290:2549–2555).

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“The period of post-injury recovery is critical during the first week,” Michael McCrea, PhD, Director of the Neuroscience Program at Waukesha Memorial Hospital and Assistant Professor of Neurology at Medical College of Wisconsin, told Neurology Today. Dr. McCrea, who led the study on acute effects of concussion, said: “The brain remains in a vulnerable state for a period of time after a concussion, during which a person has not yet returned to full functioning and is more susceptible to a recurrent injury, almost as though the threshold for injury had been lowered.”

The study reviewed the records of 1,631 football players from 15 US colleges for the years 1999, 2000, and 2001. All players underwent preseason baseline testing on concussion assessment measures. Post-incident scores for each individual suspected of having sustained a concussion were compared with baseline scores from the Graded Symptoms Checklist, Standardized Assessment of Concussion, Balance Error Scoring System, and a neuropsychological battery.

Ninety-four players with concussion (based on AAN criteria) and 56 non-injured controls were assessed for symptoms, cognitive function, and postural stability immediately, three hours, and up to seven consecutive days – days 1, 2, 3, 5, and 7 – and 90 days after injury. On average, the collegiate football players required seven days to reach full recovery from symptoms and deficits that resulted from concussion.

Approximately 10 percent of players who had a concussion required more than seven days to return to their baseline scores, highlighting the value of using measuring tools for the management of injured athletes and the risk of simply applying an automatic seven-day waiting period.



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The findings provide evidence that a revised definition of concussion may be in order, one that de-emphasizes loss of consciousness, and stresses alteration in consciousness or mental status, Dr. McCrea said. “All head injuries should be viewed as having potentially serious implications, even if they seem insignificant at the moment of contact,” he added.

“We have come a long way to refine the definition,” Dr. McCrea said. Emergency medicine textbooks from only five years ago include loss of consciousness as a defining characteristic of concussion, while our studies and others clearly illustrate that concussion also occurs in the absence of any observed loss of consciousness or profound amnesia.”

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The second study reviewed records of athletes who sustained a “second impact syndrome,” that is, they had a concussion, resumed competition before reaching full recovery, had a second concussion, usually close in time to their first injury, and experienced rapid neurological deterioration soon thereafter. The syndrome triggers a cascade of neurophysiologic events within four to six hours after the injury that include neurochemical dysregulation, engorgement of blood vessels in the brain, massive swelling throughout the brain that often causes herniation at the brain stem level, and leads to respiratory failure, said Kevin M. Guskiewicz, PhD, Associate Professor of Exercise and Sport Science and Director of Sports Medicine Research Laboratory at the University of North Carolina-Chapel Hill. Dr. Guskiewicz led the second study on the cumulative effects of concussion.

In the classic scenario, he explained, the player collapses on the playing field and cannot be revived, having suffered irreversible neurologic damage. As many as half of these players die as a result of the injury.

The cumulative effects study reviewed the records of 2,905 football players from 25 US colleges, tested at preseason baseline in 1999, 2000, and 2001. Players who had a concussion were monitored until their symptoms resolved and were followed up for repeat concussions until they completed their collegiate football career or up to the end of the 2001.

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In-season repeat concussions occurred within seven days of the first injury in 75 percent of the cases; 91.7 percent occurred within 10 days of the first injury. In one-third of the players who returned to play on the same day of injury, symptoms were delayed (present after three hours of injury) compared with one-eighth of players who did not return to competition on the same day of their injury.

Football players with a history of multiple concussions had a longer course to recovery. Although no association between concussion history and loss of consciousness or amnesia was observed with subsequent concussions, these symptoms tended to be associated with a slower recovery. Thirty percent of those with three previous concussions had symptoms lasting more than a week compared with 14.6 percent of those with one previous concussion.

Concussion was more likely to occur in players who had already had one – more than one-third of injuries were designated as “repeat injuries.” Players with a history of three or more previous concussions were three times more likely to sustain a subsequent concussion than those with no concussion history.

“Football is not an unsafe sport,” said Dr. Guskiewicz. “The message of this study is that it is very important to make sure the athletes are asymptomatic before returning to play. For years we have been looking at the seven-day waiting period without having any objective evidence for it, and this is the first paper to provide it.”

He credited increased awareness about the dangers of repeat concussion for the lower incidence of such injuries among high school and college athletes over the last few years.

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“These two studies provide excellent evidence to support what we advise about concussion,” said Jay H. Rosenberg, MD, Clinical Professor of Neurology at the University of California-San Diego, and co-author of the 1997 sport concussion guideline by the AAN Quality Standards Committee. Dr. Rosenberg has been involved in a nationwide effort to help train high school coaches to recognize concussion, and to use the Sideline Assessment of Concussion, a brief screening instrument – similar to those used in the NCAA concussion study – designed for the use by athletic trainers, coaches, and sideline medical personnel.

Dr. Rosenberg said concussion is a more critical issue at the high school level than in college sports because medically trained personnel are usually not on site to make the necessary neurological assessment for the younger players. The task usually falls to coaches. “We advise coaches to get baseline evaluations of all their players before the season for comparison,” he said.

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✓ Two new studies sponsored by the National Collegiate Athletic Association examine recovery rates from concussion in collegiate football players, and offering evidence-based information for managing concussion and preventing serious complications.

©2004 American Academy of Neurology