According to background information in the article, overall, concussion is one of the most common injuries in many collegiate sports. Recent data from the National Collegiate Athletic Association (NCAA) Injury Surveillance System reveal that concussion accounted for a significant percentage of total injuries among athletes participating in collegiate ice hockey, football, and soccer during the 2002-2003 season. Studies in basic neuroscience have demonstrated that mild traumatic brain injury (concussion) is followed by a complex cascade of events that can adversely affect cerebral function for several days to weeks. Clinically, concussion can result in neurological deficits, cognitive impairment, and other symptoms. Lack of data on recovery time following a sport-related concussion has hampered clinical decision making about when it is appropriate for an athlete to return to play after the injury.
Michael McCrea, Ph.D., of the Neuroscience Center, Waukesha Memorial Hospital, Waukesha, Wis., and colleagues conducted a study to measure the effects of concussion and the time course to recovery following the injury in competitive athletes participating in collegiate football. The study included 1,631 football players from 15 U.S. colleges. All players underwent preseason baseline testing on concussion assessment measures in 1999, 2000, and 2001. Ninety-four players with concussion (based on American Academy of Neurology criteria) and 56 noninjured controls underwent assessment of symptoms, cognitive functioning, and balance stability immediately, 3 hours, and 1, 2, 3, 5, 7, and 90 days after injury.
A total of 79 players with concussion (84 percent) completed the protocol through day 90. Compared with controls, players with concussion exhibited more severe symptoms, cognitive impairment, and balance problems immediately after concussion. On average, symptoms gradually resolved by day 7, cognitive functioning improved to baseline levels within 5 to 7 days, and balance deficits dissipated within 3 to 5 days after injury. Mild impairments in cognitive processing and verbal memory evident on neuropsychological testing 2 days after concussion resolved by day 7. There were no significant differences in symptoms or functional impairments in the concussion group and the control group 90 days after concussion.
"These findings suggest that clinicians cannot necessarily expect that all collegiate football players will reach a complete recovery within 7 days after a concussion, as approximately 10 percent of players in this study required more than a week for symptoms to fully resolve. Furthermore, not all players demonstrated the same pattern of recovery in symptoms, cognition, and balance," the authors write.
"There was clear and consistent evidence of cerebral dysfunction in cases of concussion without classic indicators of mild traumatic brain injury, such as loss of consciousness and posttraumatic amnesia. These data support a movement in the neurosciences toward a revised definition of concussion that emphasizes an alteration (as opposed to a loss) of consciousness or mental status as the hallmark of concussion and stresses the potential seriousness of all head injuries, even what has historically been referred to as a simple 'ding.' Sports medicine professionals especially should be aware that the diagnosis of concussion does not require loss of consciousness, significant amnesia, or other focal neurological abnormalities associated with more severe head injury," the researchers add. (JAMA. 2003;290:2556-2563. Available post-embargo at JAMA.com)
Editor's Note: This research was funded in part by the NCAA and the National Operating Committee on Standards for Athletic Equipment (NOCSAE). The National Center for Injury Prevention and Control and the University of North Carolina Injury Prevention Research Center also contributed to the success of this project.
FOOTBALL PLAYERS WHO SUSTAIN A CONCUSSION MORE SUSCEPTIBLE TO ADDITIONAL CONCUSSIONS
In a related article in the November 19 JAMA, Kevin Guskiewicz, Ph.D., A.T.C., of the University of North Carolina, Chapel Hill, and colleagues estimated the incidence of concussion and repeat concussion among collegiate football players. The authors also examined the association between history of previous concussions and the likelihood of experiencing recurrent concussions, and compared time to recovery following concussion between athletes with a history of previous concussion compared with those without a previous concussion.
Approximately 300,000 sport-related concussions occur annually in the United States, and the likelihood of serious adverse effects may increase with repeated head injury, according to background information in the article.
This study included 2,905 football players from 25 U.S. colleges who were tested at preseason baseline in 1999, 2000, and 2001 on a variety of measures and followed up to ascertain concussion occurrence. Players injured with a concussion were monitored until their concussion symptoms resolved and were followed up for repeat concussions until completion of their collegiate football career or until the end of the 2001 football season.
During follow-up, 184 players (6.3 percent) had a concussion, and 12 (6.5 percent) of these players had a repeat concussion within the same season. "There was an association between reported number of previous concussions and likelihood of incident concussion. Players reporting a history of 3 or more previous concussions were 3.0 times more likely to have an incident concussion than players with no concussion history," the authors write. "Headache was the most commonly reported symptom at the time of injury (85.2 percent), and mean overall symptom duration was 82 hours. Slowed recovery was associated with a history of multiple previous concussions (30.0 percent of those with 3 or more previous concussions had symptoms lasting greater than 1 week compared with 14.6 percent of those with 1 previous concussion). Of the 12 incident within-season repeat concussions, 11 (91.7 percent) occurred within 10 days of the first injury, and 9 (75.0 percent) occurred within 7 days of the first injury."
"Given our finding of a 3-fold greater risk of future concussions following 3 concussions vs. no concussions, athletes with a high cumulative history should be more informed about the increased risk of repeat concussions when continuing to play contact sports such as football," the researchers write. "Additionally, we found that 1 in 15 players with concussion may have additional concussions in the same playing season and that these reinjuries typically take place in a short window of time (7-10 days) following the first concussion." (JAMA. 2003;290:2549-2555. Available post-embargo at JAMA.com)
Editor's Note: This research was funded in part by the NCAA and the National Operating Committee on Standards for Athletic Equipment (NOCSAE). The National Center for Injury Prevention and Control and the University of North Carolina Injury Prevention Research Center also contributed to the success of this project.
EDITORIAL: UNDERSTANDING SPORTS-RELATED CONCUSSIONS
In an accompanying editorial, Douglas B. McKeag, M.D., M.S., of the Indiana University School of Medicine, Indianapolis, writes that the articles by Guskiewicz et al and McCrea et al on mild traumatic brain injury (TBI) in college football players help to provide an opportunity to see where there is agreement and evidence-based consensus on concussion.
"First, any athlete with a concussion should be removed from competition. Second, no athlete should return to play or practice until he or she is completely asymptomatic at rest and with exertion. Third, any athlete with a prolonged loss of consciousness or evidence of amnesia should not return to play that day. Fourth, careful and repeated assessments by individuals with training and experience in evaluating concussive injuries should be the rule. Fifth, any patient with a concussion whose symptoms evolve downward requires immediate neurologic evaluation and possible hospital admission."
"Now is the time to consider sports-induced mild TBI differently. Several collaborative efforts have provided an opportunity to move in this direction. Using these suggestions, clinicians caring for athletes and sports medicine researchers need to identify more areas of agreement while continuing research on the substantial knowledge gaps that remain. The picture is coming into focus but still remains a bit fuzzy," he writes. (JAMA. 2003;290:2604-2605.
Available post-embargo at JAMA.com)
For More Information: Contact the JAMA/Archives Media Relations department at 312-464-JAMA (5262) or email: mediarelations@jama-archives.org.
To contact Michael McCrea, Ph.D., call Julie Well at 262-569-0552.
To contact Kevin Guskiewicz, Ph.D., A.T.C., call David Williamson at 919-962-8596.
To contact editorial author Douglas B. McKeag, M.D., M.S., call Joe Stuteville at 317-274-7722.
INFORMATION CONTAINED IN THESE NEWS RELEASES IS PROTECTED BY COPYRIGHT. JOURNAL ATTRIBUTION IS REQUIRED.
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