One of the biggest hurdles to appropriate clinical management of sports concussion is identifying athletes for an initial assessment on the sports sideline. Many sports concussion go undetected, say experts, either because athletes don't recognize that they have symptoms of concussion or fail to self-report such symptoms, or because sideline personnel or game officials lack the necessary training and experience to identify an athlete requiring assessment.
The evidence that concussions are significantly under-reported, and that increased education alone will not solve the problem, is substantial:
- An oft-cited 2004 study (1) pegged the percentage of concussions that weren't reported at more than 50%;
- A 2010 study (2) of two Canadian junior ice hockey teams, comprised of athletes ranging in ages from 16 to 21, found that for every concussion self-reported by the players or identified by the coaches or on-the-bench medical personnel physician observers in the stands picked up seven, a rate of 21.5 concussions per 1,000 man-games, or nearly seven times greater than the 3.1 concussions per 1,000 man-games reported in an earlier study of NCAA Division I hockey programs; (3)
- A 2012 anonymous online survey (4) of college athletes at the University of Pennsylvania reported that 27% of athletes in contact sports said they had hidden a concussion to stay in a game, and more than half (54%) said they would be extremely unlikely or unlikely to report a concussion in a game situation, similar to the 30.4% of athletes who admitted to continuing to play while experiencing symptoms after being hit in the head reported in a 2003 study, with the percentage of football players exhibiting this behavior even higher (61.2%). (10)
- A 2012 study (9) of men's and women's university hockey teams in Canada found a significantly higher concussion rate than previous studies, which the authors noted, had depended on either the retrospective self-reporting of athletes who are reluctant to report their injuries or the judgment of a certified athletic trainer.
- A 2013 study (13) of 120 high school football players, 30 of whom had suffered a concussion and 82 of whom had reported receiving prior concussion education, found that, while most correctly recognized the symptoms of concussion and 9 out of 10 recognized the risk of serious injury if they returned to play too quickly:
- an astounding 91 percent felt that it was okay for an athlete to play with a concussion
- 75 percent said they would play through any injury to win a game
- 53 percent said they would "always or sometimes continue to play with a headache sustained from an injury,"
- Only 54 percent would "always or sometimes report symptoms of a concussion to their coach," and
- Only 4 in 10 would tell their coach immediately if they had concussion symptoms.
Early identification is critical
Early identification on the sports sideline of suspected concussion is critical because, in most cases, athletes who are immediately removed from contact or collision sports after suffering a concussion or other traumatic brain injury (TBI) will recover without incident fairly quickly (although a 2012 study5 suggests that full cognitive function may take longer to return for high school student-athletes, especially girls). If an athlete is allowed to keep playing, however, their recovery is likely to take longer, and they are at increased risk of long-term problems (e.g. early dementia, depression, more rapid aging of the brain, and in rare cases, chronic traumatic encephalopathy, and in extremely rare instances, catastrophic injury or death.
Reasons are largely cultural
Despite increased awareness about concussions in recent years, some of those involved in contact and collision sports still don't seem as concerned as they should be about the risks. The Canadian hockey study (2), for example, "described a culture in which concussions were not treated as a serious health issue or, it seemed, an issue at all. Players described being under pressure from their coaches to continue playing even when they'd been told by medical professionals that they'd suffered concussions and should take time off."
The attitudes of some of the Canadian hockey parents was even more puzzling. One told the research team that it should leave the team and let his child go back to thinking about hockey instead of the potential for injury." (3) "The reluctance to report concussion symptoms and to follow protocols [were] likely results from certain cultural factors such as athletes asserting their masculinity by playing through the discomfort of an injury, and a belief that winning is more important than an athlete's long-term health," said lead author, Paul Echlin, M.D. There is no reason to believe that athletes playing football and other contact and collision sports in the United States are any different.
While all but a handful of states now have laws requiring immediate removal from play of athletes with concussion signs or symptoms and prohibit same-day return to play for those with suspected concussion, some are concerned that such laws may have the perverse effect of making the under-reporting problem even worse, fearing that an athlete is going to be even less likely to self-report experiencing concussion symptoms and more likely to hide symptoms from teammates, game officials and sideline personnel if they know that a suspected concussion may sideline them for the rest of the game.
Is technology the answer?
As several studies (4,13) demonstrate, increased education, by itself, does not appear to be effective in increasing the rate of self-reporting by athletes, leading Brit Anderson, MD, an emergency medicine fellow at Cincinnati Children's Hospital and the lead author of the most recent study (13), to conclude that "other approaches, such as an increased use of sideline screening by coaches or athletic trainers, might be needed to identify injured athletes." (14)
What then is the best way to address the problem of under-reporting? It may be to avoid relying on athletes themselves, game officials and/or sideline observers to call for a concussion assessment, but to instead employ technology to get around the problem altogether through widespread real-time monitoring of head impact exposure (e.g. number, severity, location, and cumulative impact) at all levels of football, and other helmeted and non-helmeted contact and collision sports where practical, to identify high risk impacts and alert medical personnel on the sideline to perform a concussion assessment. (6,11,12,15).
"The identification of a potentially injurious impact or series of impacts via real-time monitoring of head impact exposure in athletes may [not only] facilitate the early recognition and management of brain injury in helmeted sports," argues Richard M. Greenwald, PhD of the Thayer School of Engineering at Dartmouth College, lead author of an editorial in the March 2012 Clinical Journal of Sports Medicine,6 but "permit early intervention, potentially in advance of an injury, rather than simply as a management tool postinjury."
Benefits of real-time hit monitoring
While monitoring will not eliminate brain injuries altogether, the benefits of early identification and prevention of further injury are numerous:
- Sideline personnel will benefit from objective data that might inform their medical decisions (6,11,13,15);
- Parents will benefit from reduced reliance on honest self-reporting of concussion symptoms by athletes and of the less-than-perfect observational skills of sideline management in spotting signs of concussion;
- Teams will benefit by having healthy, unimpaired athletes on the field more often; and
- The student-athlete and professional athlete will benefit the most from reduced exposure to potentially injurious blows and from the "conundrum of having to self-report an injury that they may not recognize as being potentially injurious or dangerous in the moment of competition."
As co-founder of Simbex, LLC, the Lebanon, New Hampshire company that makes the HITS (Head Impact Telemetry System) - a peer-reviewed, scientifically-validated technology used by researchers in biomechanical studies to measure head impacts on the playing field - Greenwald knows a thing or two about the technology of head impact exposure monitoring. That his company might benefit from the widespread monitoring he and his colleagues at Simbex propose in the editorial, however, does not make their recommendation any less important.
Writing about head impact sensors in the March 2013 issue of the British Journal of Sports Medicine, (11) Jeffrey S. Kutcher, MD, of the Department of Neurology and Michigan Neurosport at the University of Michigan, observes that the "development of easily deployable sport equipment-based accelerometer systems ... provide[s] two unique and potentially useful, clinical opportunities:
The first is the ability to monitor impacts during the course of an athletic event for the purpose of screening for potential injury. Although many researchers have analyzed impact counts and characteristics across a variety of settings in the hopes of establishing force 'thresholds' for injury, no such threshold has been discovered. As efforts to improve impact-monitoring accuracy continue, however, so will the search for the 'concussion threshold.' At the same time, there may be a separate, but similar role for the real-time tracking of impact forces. Although an on-board acceleromter system may not be able to accurately predict injury, it may have utility as a screening device by alerting sideline personnel of an impact that has occurred above a predetermined magnitude that triggers either observation or clinical evaluation of an athlete. Although there are currently no published studies to support the use of impact sensor systems in this manner, and a 'concussion threshold' is unknown, the potential clinical utility should be carefully considered.
The second potential clinical benefit of impact monitoring systems stems not from the idea of monitoring impacts for the presence of an acute injury-generating hit, but from the potential advantage of acruately cataloguing the number of hits and post-impact head acceleration being experienced by an athlete over time. Some have suggested that the idea of a 'hit count' that is kept for athletes over the course of a game, practice, week, month, season or career. This concept is fairly new and, as yet does not have published data to suggest that any particular level or number of hits has significant clinical meaning for any particular sport or position. Nonetheless, individual athletes may feel there is a benefit to having an estimate of forces their brain experiences over time.
Head impact monitoring systems
The day when monitoring of head impact exposure in football and other helmeted sports becomes commonplace may be closer at hand than one might think, as a number of helmet sensor products are already on, or about to come on, the market designed to capture the kind of data that not only Greenwald and his colleagues, but other concussion experts say is needed as a way around the underreporting/under-identification problem.Shockbox
One football helmet sensor product which came on the market in fall 2012 is the ShockboxTM wireless impact sensor from Impakt Protective. Once attached inside a player's helmet (a version for hockey helmets is also available; versions for lacrosse and ski and snowboard helmets are in the product development pipeline), a sensor measures the g-force of a hit to the helmet from any direction, sending data wirelessly via Bluetooth to a smart phone or laptop computer of an athletic trainer, coach or parent on the sideline and triggering an alert when the athlete suffers a head impact that may of sufficient force to be concussive so they can be checked on the sideline using standard concussion assessment tools, such as the Standardized Assessment of Concussion, Sports Concussion Assessment Tool (SCAT2) or King-Devick test.
As with other helmet sensor systems, the Shockbox is designed to give parents, trainers, coaches and team doctors a set of electronic of eyes with which to watch out for concussions that might otherwise go undetected, either because the signs were too subtle to be seen by officials, coaches, athletic trainers, team doctors or parents on the sports sideline, or because the player, out of a desire to stay in the game, failed to self-report experiencing concussion symptoms, such as headache or dizziness, that warrant, at the very least, further evaluation.
The Shockbox can also count the number of hits. Both Greenwald and the Sports Legacy Institute in its recent "Hit Count" proposal suggest limiting the number of hits as a way to reduce exposure to repetitive sub-concussive hits, the kind which one recent study found can lead to at least short-term cognitive impairment among high school football players (at least among those experiencing 150 or more hits in the 40 to 80 g range during a single week of practice and games).
While capable of tracking hits anywhere from about 30g up to over 200g, the Shockbox is calibrated to only capture hits at around the 50 g or higher level. The reason, says Impakt Protective's CEO, Danny Crossman, is that studies show that 96% or more of the impacts in hockey and 85% plus in football are below the 50g level. Such device settings are also, says Crossman, designed to balance false positive and false negative alerts so that parents and teams will be more likely to continue using the Shockbox system. Too many false positives, he says, and the device would end up like a car alarms: "Because they go off all the time, no one ever pays attention to them anymore."
i1 Biometrics Impact Sensing Mouth Guard
Another head impact exposure sensor system on the market is Battle Sports Science's Impact Indicator, which uses highly sophisticated technology and proprietary software embedded in football and hockey helmet chinstraps to measure the G-force and duration of hits sustained by an athlete's head during play and flashes red when a force is transmitted to the head that exceeds safe thresholds, alerting game officials and sideline personnel to check an athlete for signs or symptoms of concussion (even if they haven't observed any signs and/or the athlete hasn't self-reported experiencing any symptoms).
As with any helmet sensor, the Impact Indicator will not prevent or detect concussions or diagnose one; it's simply another set of eyes to assist coaches, parents and players in determining whether further assessment is warranted, Chinstraps are now available for football and hockey helmets, and a version for lacrosse - another sport with high concussion rates - will be in stores soon.
Another product, this one from Safebrain Systems, Inc. of Canada, will, according to the company's website, capture real-time G-force data from a quarter-sized, battery-powered accelerometer and microprocessor attached with a special double-sided adhesive to an athlete's helmet. Data is sent to a laptop on the sideline loaded with the Safebrain System software, and an LED indicator light notifies sideline training staff of an athlete who has sustained an impact that could potentially have caused a traumatic head injury. The system is sold as a package with sensors and software for team use only, not individually.
In addition to its use in research, the HITS axial accelerometers are currently being used by a number of college football programs, including those at the University of Oklahoma and Virginia Tech, as a tool in identifying athletes who may have sustained blows to the head that could cause traumatic brain injury. The University of North Carolina uses the system, along with video, to help improve athletes' tackling technique to avoid direct blows to the head. While the HITS system is costly, and thus beyond the reach of most football programs, a lower-cost version for use on the sports sideline at the high school and youth level is in the product research and development pipeline, Greenwald says.
As remarkable as these technologies may be, they are not without their critics. As Dr. Robert Cantu notes in his 2012 book, Concussions and Our Kids (3), "there are some biomechanists who believe Simbex does an excellent job measuring hits that go through the center of gravity of the head (e.g., a hit right through the ear hole of a helmet or squarely in the middle of your forehead), but is not precisely accurate in measurements of hits off the center of gravity. A hit that primarily swivels the neck and head may be inaccurately recorded by Simbex." Without specifically mentioning the Battle Sports' Impact Indicator by name, Dr. Cantu also expressed skepticism about chin strap sensors: "To think that a kid with concussion symptoms might not be evaluated because a light bulb failed to turn red," he argues, is "disturbing and dangerous."
Similar concerns have been expressed by Dr. Kevin Guskiewicz, a member of the NFL's Head, Neck and Spine Medical Committee who oversees equipment-related issues, a professor in the Department of Exercise and Sport Science, and at the University of North Carolina. "There are no published data to suggest that impacts registered by the chinstrap are representative of the accelerations experienced by the head and brain, which is of greatest interest in the study of concussions," Guskiewicz told Wired magazine through an email provided by the NFL. "Until sound research studies can illustrate this, these devices are not recommended for concussion prevention or concussion identification by our HNS subcommittee on safety equipment."
Recent data from Wayne State University (7), also appears to show that the HIT system may be unreliable in terms of providing accurate head acceleration data during head impacts in a football game because it is validated against a very tight fitting (medium-sized) helmet on a dummy head applying contact pressures between the helmet and head way above the comfort level of human volunteer subjects who tested both medium and large sized helmets, with the data showing that large absolute errors occur when a comfortable helmet is worn by the players. (8)
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Posted May 15, 2012; most recently revised May 17, 2013