Our Use of Tools for Assessing Concussion Is Inconsistent
Bert R. Mandelbaum, MD, DHL (hon)
May 27, 2015
This is the first of a new series of columns, Sideline Consult, in which key opinion leaders in sports medicine offer what are in effect master classes for physicians on key areas of the specialty in which controversy, confusion, or ignorance often exists.
Kicking off the series is Bert R. Mandelbaum, MD, of the Santa Monica Orthopaedic and Sports Medicine Group in Santa Monica, California. Dr Mandelbaum is co-chair of the Medical Affairs Institute for Sports Sciences; chief medical officer for the 2015 Special Olympics World Summer Games in Los Angeles, California; and staff physician for the Los Angeles Galaxy soccer team, the US Soccer Federation, and Pepperdine University's athletic programs. In addition, he is a member of the Fédération Internationale de Football Association (FIFA); the Confederation of North, Central American and Caribbean Association Football (CONCACAF) Medical Committee; and the FIFA Medical Assessment and Research Centre, as well as assistant medical director of Major League Soccer. Dr Mandelbaum is a coauthor of dozens of clinical studies on sports medicine subjects. He is author of The Within Win: Capturing Your Victorious Spirit.
Concussion: A Progress Report
To read the media headlines, you'd think sports physicians, other healthcare personnel, athletic directors, coaches, and trainers don't know anything about concussions.
It seems that every day we read about another athlete suffering from chronic traumatic encephalopathy. The National Football League, the National Hockey League, the National Collegiate Athletic Association, US Soccer Federation, and other sports organizations are facing lawsuits for not preventing head injuries. New activist groups are demanding rule changes.
We're a long way from preventing all concussions, and we still have a lot to learn about the best way of preventing them. One concussion is one too many.
But with all of this clamor, it's hard to hear the sound of the progress being made.
Over the past couple of decades, researchers have developed and validated a number of assessments that can determine whether head trauma is serious enough to warrant further evaluation. Little by little, sports teams, schools, clubs, leagues, and sports associations are developing best practices for these tools.
Tools for Concussion Assessment
The American Association of Neurological Surgeons defines concussion as a "clinical syndrome characterized by immediate and transient alteration in brain function, including alteration of mental status and level of consciousness, resulting from mechanical force or trauma."
Many concussed athletes may appear asymptomatic or even conceal their symptoms. Screening tools administered on the sidelines can quickly identify those most likely to have suffered from a concussion. Team physicians, trainers, coaches, or even parents can then refer these athletes for a definitive diagnosis and care.
Among the many sidelines screening tools available, the evidence validating the King-Devick Test, Sport Concussion Assessment Tool (SCAT), and Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is particularly strong. These are all fairly easy to use and do not require medical training.
Teams should administer their assessments at the beginning of each season to establish a baseline and again each time a head injury is suspected.
SCAT. A group of experts developed the SCAT, 3rd Edition (SCAT3) at the 4th International Consensus Conference on Concussion in Sport in 2012. It combines elements of other standard measures of neurologic function, including the Glasgow Coma Scale, the Standardized Assessment of Concussion, the Maddocks questions for assessing concussion, and the Balance Error Scoring System. It takes about 20 minutes to administer.
The authors of the test advise that only medically trained people administer this test. For lay people, they recommend the simpler Concussion Recognition Tool. For athletes 12 years old and younger, they recommend the Child SCAT3.
Several of the component tests used in the SCAT3 have been validated separately in a variety of studies.
King-Devick Test. The King-Devick was developed in 1976 as a test of saccades as they relate to reading performance. Since 2011, multiple studies have shown a close correlation between scores on the King-Devick and a wide range of neurologic conditions, including concussion.
The King-Devick consists of a 2-minute test that requires an athlete to read single-digit numbers displayed on cards, a laptop, or an iPad. Lines of the numbers become increasingly difficult to track with successive cards. Participants read the numbers on each card from left to right as quickly as possible without making errors.
After suspected head trauma, if the time needed to complete the test is any longer than the athlete's baseline test time, the athlete should be removed from play and evaluated by a sports physician or other qualified medical professional.
In one study, researchers compared the results on the King-Devick to results of the Military Acute Concussion Evaluation (MACE) in mixed martial arts fighters. The MACE requires 15-20 minutes to administer and includes cognitive history, memory and orientation testing, and a neurologic screening.
Worse post-fight King-Devick scores and greater worsening of scores correlated well with worse post-fight MACE scores. Since then, many other studies have validated the King-Devick in other sports.
ImPACT Test. The ImPACT Test is computerized and takes about 25 minutes to complete. Its maker offers certification courses and recommends that it be administered by a specially trained athletic trainer, school nurse, athletic director, team doctor, or psychologist.
The test measures player symptoms, verbal and visual memory, processing speed, and reaction time. Unlike the King-Devick Test, the ImPACT Test alternates modules to prevent a learning effect from distorting the results.
In one validation study, researchers tested athletes at the University of Pittsburgh in Pittsburgh, Pennsylvania. They compared the results of the ImPACT Test with diagnoses of trainers and physicians. They found a correlation between the professionals' diagnoses and the ImPACT results, even when the athletes denied their symptoms.
The Sideline ImPACT test is an abbreviated version of the ImPACT Test available as an iPhone application. It takes 5 minutes to administer and measures concentration, short-term memory, and orientation. The manufacturer warns that this version shouldn't be used to make return-to-play decisions.
Although most professional teams and many collegiate teams are using such tests, their use is much less consistent at the high school and club level. Concussions are common at this level, and I'd like to see both baseline and sideline assessment become standard throughout competitive sports.
Testing athletes before return to play won't prevent concussions; it will only catch those that have already occurred. But it will prevent athletes from returning to play too soon. The risk for more serious brain damage is likely to be greater when a player sustains a second head injury before the first one heals. The number-one goal is always prevention!
The Future of Concussion Assessment
Other interesting technologies are being developed. One device I'm following with interest is a wireless head impact sensor module by X2 Biosystems (xPatch®; Seattle, Washington). This small, light-weight accelerator can transmit information about head acceleration to the sidelines. Another is the Triax™ system (Triax Technologies, Inc.; Norwalk, Connecticut), a monitor attached to a headband that can measure the force of any impact and calculate the "dose of brain trauma" over time. We soon will be able to calculate a dose beyond which the athlete will not be allowed to return to play.
So what else can prevent concussions?
- Heads Up: The Heads Up Football program promoted by USA Football shows promise in reducing concussions by teaching players not to use their heads in tackling.
- In soccer, proper ball size and heading technique can reduce the impact of the ball. In essence, players should hit the ball and not the other way around.
- Rules enforcement: Good enforcement of rules can greatly reduce head injury. Football referees should prevent all use of the head in tackling. In soccer, FIFA reported that the number of serious head injuries in tournaments dropped by half after the league introduced a 2006 policy ejecting players who deliberately strike an opponent's head with an elbow. In addition, FIFA, the Union of European Football Associations, and CONCACAF have instituted a 3-minute break in a game with significant head trauma to allow doctors to assess the situation with the tools mentioned above.
- Neck strengthening: While there's little research to show that neck strengthening can prevent concussions at this time, at least one study suggests that it can reduce the risk for cervical spine injuries.
- Headgear: The research on headgear has been controversial. While helmets protect against injury to the skin and skull in a sport like hockey, they may not adequately reduce the acceleration that damages the brain. More studies are needed.
Sports medicine professionals have a lot of work ahead of us in reducing the rate and the impact of concussions, and we're not likely to eliminate them. But using the knowledge we already have would put us on the right track.