The King-Devick Test: The Missing Link to Practical Management of Concussions

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One of the most discussed and controversial issues occurring in the sport today is that of concussions and its head-banging blow to young athletes in this country. Most of the media is concerned with the alarming rise in the rate of the number of concussions being seen in high school level sports. Children and teenagers are more likely to get a concussion than an adult, and take longer to recover from concussions, according to the Centers for Disease Control (CDC). The American Academy of Family Physicians estimates that as many as 250,000-plus concussions occur each year at the high-school level.

Physical activity and sport by their very nature include inherent risks leading to injuries for many individuals who participate. Most sports injuries encountered by young athletes are minor in nature, and present an identifiable time period and protocol for management and recovery before the athlete can return to play. Because of the varying magnitudes and locations of impacts resulting in a concussion, as well as other factors, each athlete responds differently to the various forces during a head injury. No two concussions follow the same recovery patterns and two milder injuries (sub-concussive impacts) may do more damage than one severe one. This makes it difficult to diagnose and treat.

All concussions are serious, and ignoring the signs and symptoms of a concussion increases the risk of suffering another, more serious head injury—even neurological impairment and depression. For this reason, any athlete who suffers head injury that causes any symptoms of a concussion—such as chronic headaches, fatigue, sleep difficulties, sensitivity to light and noise, dizziness, and short-term memory loss—should stop play and receive a medical evaluation. Any player who has any loss of consciousness or post-injury amnesia should seek immediate medical attention.

A single, first-time concussion often heals without incident. But before it heals, it makes a person extremely vulnerable to brain damage from a second head trauma. Returning to the game too soon can slow healing and cause repeat concussions with long-term consequences. The CDC reports that rest is the only way to heal brain injuries, such as concussions.

The assessment of a concussion, as well as determining when an athlete should return to play, remains a matter of controversy within the medical community. A 2009 study from the Center for Injury Research and Policy at Nationwide Children’s Hospital in Columbus, Ohio discovered that 41% of high school athletes return to action too soon following a concussion. The sports healthcare community are coming together to re-assess past definitions, tests and protocol; recommend new assessment tools; devise a new standard of care and management protocols; and create new “return to play” rules and guidelines based upon new found  research.

Researchers have long known that reaction time is slower immediately after a concussion, and this delayed reaction time often lasts several days after other concussion symptoms are gone. The problem has generally been that the tests and equipment currently used to measure an athlete’s reaction time are elaborate and require computers and special software. That is not so practical and handy when you’re on the field or on the sidelines.

The King-Devick (K-D) Test just may be “the missing link” that is needed for practical sideline management of concussions. Pennsylvania School of Medicine researchers showed that the test was superior to current methods and accurately and reliably identifies athletes with head trauma.

The K-D Test is an old visual recognition and reaction time test that has been utilized for over 25 years to track eye movement and detect reading difficulties. This test may help identify athletes who have a head injury that is serious enough to require time off from sports. The test involves an athlete reading and calling out single digit numbers displayed on index-sized cards. A baseline test is given at the start of the season (40 seconds is about normal). Any increase (worsening) in the time needed to complete the test suggests a concussion has occurred, particularly if the delay is greater than five seconds compared to the individual’s baseline test time.

While other sideline exams test cognitive or memory skills and rely on the administrator to make subjective decisions, the K-D Test is objective and it reveals impairments of eye movement, attention, language and other symptoms of impaired brain function that are frequently abnormal following a concussion.

This is not to say that all other testing, assessment and protocols are unnecessary. But The King-K-D Test just may be “the missing link” that needs to be incorporated into all Comprehensive Concussion Management Programs that includes: a pre-participation physical exam (PPE); a head injury/concussion symptom questionnaire along with a preseason standardized assessment of concussion, which is called a SAC Test, as part of the PPE; a computerized baseline assessment from one of the following every year: SCAT 2, ImPact Test, or Axon Test; a preseason balance test called the BESS Test along with the King-Devick Test that can be incorporated into a Sideline Screening/Assessment; and, finally, an educational session with athletes, coaches and parents/guardians.

Most of these tests need to be administered by a sports healthcare provider. But what makes The K-D Test so useful is that it’s easy to understand, easy to learn and simple to administer. It can be a very valuable part of a sideline/screening assessment for concussions that everyone can learn just like CPR/AED and Sports First Aid. The K-D Test can become a part of the Standard of Care for ALL who are involved with the healthcare of young athletes.

It is “the missing link” to the objective screening and the practical management of concussions.

Dr. Enrico N. Esposito
Dr. Esposito is the Chair of Sports Medicine at the United States Sports Academy. He has an extensive background in sports medicine, sports chiropractic and sports performance coaching at various levels from Pee Wee to Professional/Olympic caliber. He is a chiropractic physician with professional certifications in athletic training, strength and conditioning, rehabilitation, exercise physiology and sport safety.

Editor’s Note:
Dr. Esposito conducts ongoing research in human athletic performance and has a special interest in studying new ways to help prevent concussions, especially among young athletes. Anyone interested in this topic can read more by clicking on the links below. Dr. Esposito teaches courses on sports medicine at the United States Sports Academy. For more information, go to http://www.ussa.edu.

Sources of more information on the King-Devick Test: