Nov. 19, 2003 CHAPEL HILL -- Enduring the painful head-banging injury known as concussion boosts the chance that college football players -- and possibly other athletes -- will suffer a second concussion during the same season, a new study concludes.
College football players reporting a history of three or more concussions are three times more likely to be similarly injured again than players with no concussion history, the University of North Carolina at Chapel Hill-led study shows.
In a second, closely related investigation, the same researchers found that concussed players scored worse on thinking and memory tests and displayed more balance problems than controls on the day of the injury and afterward. Symptoms, including headaches, usually disappeared within a week, further tests revealed.
Both papers appear in the Nov. 19 issue of the Journal of the American Medical Association.
"This work, which is part of the NCAA Concussion Study, represents the largest multi-site study on recovery and outcome following sport-related concussion and is important because previously studies were faulted for being too small," said Dr. Kevin M. Guskiewicz, associate professor of exercise and sport science at UNC, lead author of the first paper and co-author of the second. "It confirmed our earlier findings and uncovered several other important concerns.
"One is that recovery is slower in players with a history of previous concussions," Guskiewicz said. "For instance, 30 percent of players with three or more concussions had symptoms lasting longer than a week, compared with only about 7 percent of those who reported no concussion history."
Ninety-two percent of repeat concussions occurred within 10 days of the first injury, and 75 percent occurred within seven days, he said.
"Our studies do not suggest that football is an unsafe sport," Guskiewicz said. "However, they do underscore the critical importance of making certain that athletes are without any symptoms before they are allowed to return to participation. Concussed players often will still be vulnerable during the first few days following the injury, but they are unlikely to sit out unless a physician or athletic trainer holds them out."
Besides Guskiewicz, UNC authors are Dr. Stephen W. Marshall, research assistant professor of epidemiology at the School of Public Health; Dr. Robert C. Cantu, adjunct professor of exercise and sport science; and Jingzhen Yang, research assistant with the Injury Prevention Research Center. Marshall and Guskiewicz hold appointments in orthopaedics at the School of Medicine and in the Injury Prevention Research Center. Cantu primarily is a neurosurgeon at Emerson Hospital in Concord, Mass.
Other authors are Drs. Michael McCrea of Waukesha Memorial Hospital in Wisconsin and Christopher Randolph and James P. Kelly of the Chicago Neurological Institute, Northwestern University’s School of Medicine and the Loyola University Medical School; Drs. William Barr of the New York University School of Medicine and James A. Onate of Boston University.
McCrea is lead author of the second paper about the acute effects of concussion, which involved 1,631 players at 15 U.S. colleges. Between 1999 and 2001, subjects underwent baseline testing of their neurological function. The 94 who suffered concussion underwent further testing immediately and then three hours and one, two, three, five, seven and 90 days post-injury, as did 56 uninjured players.
The investigation Guskiewicz led involved almost 200 concussive injuries, 25 colleges and 2,905 football players representing 4,251 "player seasons." He and colleagues found 184 players, or 6.3 percent, had a concussion during the three-year period ending in 2001, and 12 suffered at least two.
Players most likely to be concussed were linebackers, offensive linemen and defensive backs involved in collisions, tackling, being tackled and blocking, researchers found.
"About 300,000 sport-related concussions occur each year in the United States, and the chance of serious consequences such as permanent damage increases with repeated head injury," Guskiewicz said. "I’m not sure we are ever going to prevent concussions through equipment and rule changes, and so it is important to raise awareness among players, coaches, athletic trainers and physicians of the increased risk, especially in situations where a player has already had two or three concussions."
The National Collegiate Athletic Association and the National Operating Committee on Standards for Athletic Equipment supported the study, along with the National Center for Injury Prevention and Control and the UNC Injury Prevention Research Center.
The exercise and sport science department at UNC is part of the University’s College of Arts and Sciences.
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