THE PHYSICIAN AND SPORTSMEDICINE - VOL 30 - NO. 7 - JULY 2002
Brain Injury in Soccer
New Reports Highlight Unresolved Issues
The cognitive effects of head injury in soccer are still controversial, but experts at least agree on the questions that need to be answered. Apparent research contradictions, injury prevention efforts, and the focus of future research were all addressed in an October 2001 workshop sponsored by the Institute of Medicine (IOM). A summary of the workshop proceedings was published in April.1 (The proceedings are available at https://bob.nap.edu/books/0309083443/html/)
Are Neuropsychological Deficits Real?
The most recent study2 of neuropsychological performance in soccer players revealed that a sample group of US soccer players did not exhibit impairments when compared with nonsoccer and nonathletic controls. The study also examined neurocognitive performance in players who had a history of soccer-related concussions and found no differences.
The study findings seem to further the divide between what US and European researchers have found regarding soccer and neuropsychological performance. European studies have consistently documented neuropsychological impairment.
Why the difference? Many reasons have been put forth both in the IOM workshop and in the medical literature. In the IOM workshop, Donald T. Kirkendall, PhD, clinical assistant professor in the department of orthopedics at the University of North Carolina School of Medicine in Chapel Hill, pointed out that the American and European studies may not be comparable because Europeans generally use balls that are more highly inflated, which thus could create greater head impact. Kirkendall and other head-injury experts have also pointed out that findings in European professional players, who have an aggressive, highly competitive style of play, may not be applicable to American youth players. Head injury exposure among players that move on into professional play may also be greater than players who don't compete beyond college.
Possible reasons put forth in a letter to the editor in the Journal of the American Medical Association3 included differences in alcohol use between American and European players, differences in neuropsychological testing practices, and an association between concussion history and neuropsychological impairment. In an accompanying response, Erik J. T. Matser, PhD, lead author of the European studies and assistant professor in the department of anatomy, faculty of medicine and health sciences, Erasmus University in Rotterdam, The Netherlands, countered that the level of alcohol use fell within the bounds of social drinking (two drinks per day). He also pointed that one of his group's previous studies found that field position was a risk factor for neuropsychological impairment, an association that seems to implicate heading as a contributing factor.
Helmets and Other Prevention Issues
The IOM summary also covered discussions about suggestions that have been made to reduce injuries in soccer. No peer-reviewed studies support or refute the use of helmets in soccer, and the US Consumer Product Safety Commission, which looked at the issue in 2000, declined to issue a statement supporting helmet use in soccer. Joseph "Trey" Crisco, PhD, director of the bioengineering lab at Brown University in Providence, Rhode Island, and director of research for the National Operating Committee on Standards for Athletic Equipment, had a number of concerns about helmet use in soccer:
Crisco told the group that a more cost-effective safety approach might be to research and develop standards for soccer balls so that they are not likely to cause brain injury. Structure, weight, and material properties can all influence head impact. Other safety enhancements that have been enacted over the past few years include padding soccer goalposts, prohibiting heading in children younger than 10, and coaching young people on proper heading technique.
A Research Road Map
Perhaps the most contentious issue in the discussion about head injuries is the role of heading. Some experts believe that heading can produce cellular changes that lead to chronic traumatic brain injury and neuropsychiatric impairments, while others believe that concussions are the more likely culprit.
Kevin M. Guskiewicz, PhD, ATC, lead author of the most recent report2 on the neurocognitive effects of soccer, says that the positive findings of his group's study have not garnered the same level of media attention as when the European studies associated soccer with mild deficits on a few of the tests. "The good news contained in our study has still made it into the hands of many players, coaches, and parents who had some concerns 2 years ago," he says. Guskiewicz notes that his group is completing an exit assessment study of soccer players to determine if deficits are present after an additional 4 years of soccer participation (ie, beyond high school).
The IOM summary states that the long-term effects of repetitive heading will not be known until well-designed, long-term studies are performed that evaluate players before they participate and years after they play soccer.
A Better Helmet for Whitewater Sports
Two Johns Hopkins engineering students recently unveiled a new helmet design for whitewater rafters and kayakers. Currently, there are no standards for whitewater helmets, and the models now in use are often pushed up from the forehead by the force of the water, leaving participants vulnerable to serious head injuries.
One of the helmet's distinctive features is a restraint system (figure 1) that creates a tighter fit whenever the helmet encounters rotational forces, as occurs when rafters or kayakers are thrown headfirst into the water against boulders or other debris. Protection also comes from three layers of EVA foam beneath the shell of the helmet.
The momentum for the safer helmet project came from a Utah businessman who founded the Whitewater Research and Safety Institute after his son died in a 1998 whitewater kayaking accident. The Center for Injury Research and Policy at The Johns Hopkins University Bloomberg School of Public Health in Baltimore cofunded the development of the new helmet. The students who designed the helmet are Michael Cordeiro, a mechanical engineering student from Easton, Maryland, and Chang Lee, from Atlanta, who is completing a dual major in biomedical engineering and engineering mechanics.
The students' goals were to design a helmet that would not only stay in place but be lightweight, buoyant, durable, and less than $30 per helmet to manufacture. The prototype and specifications will be patented by a nonprofit foundation that will produce and sell the headgear at cost.