Should Your Athlete Return to Play After a Big Hit?
According to CDC estimates, there are approximately 3.8 million sports-related concussions annually, with about half going unreported and another substantial number that are asymptomatic. Concussions are a complex type of brain injury that is not typically visible on routine imaging of the brain, but can be detected when important areas of brain function are assessed. Vision alone accounts for over 55% of the brain’s pathways; therefore, testing specific aspects of the visual pathway can tell us a lot about brain function. One test in particular helps assess brain function before and after a suspected head trauma to determine if a person has a concussion or not.
The King-Devick Test, a Mayo Clinic endorsed test, is an objective remove-from-play sideline concussion screener that can be administered in minutes. It is an accurate and reliable method for identifying athletes with head trauma that can be performed right there on the sideline. It was originally developed to screen for eye movement disorders related to reading performance in school-aged children, but has proven useful for concussion management and as an indicator of neurological function. The King-Devick Test screens for problems with saccades (eye movements), attention, concentration, speech/language, and detects areas of sub-optimal brain function. It has been scientifically validated in more than 120 recent peer reviewed articles published in elite medical journals.
The test requires an athlete to read single digit numbers displayed on cards or an iPad as they are being timed. Athletes must establish an individual preseason baseline. A baseline score consists of the cumulative amount of time it takes to read the three tests out loud. The baseline must be completed twice and then the fastest time recorded with no errors is used as the baseline score.
Then, immediately or soon after a suspected head trauma, the athlete is given the test once. If the athlete takes more time to complete the test than during their baseline test, they should be removed from play and evaluated by a medical professional. This test is nice because a coach, athletic trainer, parent, or anyone with the proper training can administer it.It is currently being used in youth leagues, high school and collegiate programs, as well as at the professional level.
A recent study conducted by Dhawan et. al. looked at 141 youth hockey players, including 20 athletes that had been medically diagnosed with concussions. The players underwent K-D testing preseason, postseason and immediately after a suspected head trauma. Additional testing was performed in a subgroup of non-concussed athletes immediately before and after a game to determine the effects of fatigue on K-D scores. The results of the study were as follows:
- All 20 athletes with diagnosed concussions had immediate post-concussion K-D scores >5 seconds from baseline.
- All athletes without concussions had similar preseason and postseason scores.
- K-D scores were not slower due to fatigue after a game.
- The K-D Test accurately identified all diagnosed concussions immediately following the injury in these young athletes. As you can see, the K-D Test has been shown to be a useful sideline concussion screening tool. It should hopefully be implemented into all sports to help determine if an athlete should be removed from play after a head injury.
To learn about other studies using the King-Devick Test, please visit https://kingdevicktest.com/research/concussions/.
For more information on concussions and youth sports, visit https://www.cdc.gov/headsup/.
Center for Disease Control and Prevention. (January 2017). Heads Up: Concussion in Youth Sports. https://www.cdc.gov/headsup/
Dhawan, PS, et. al. (Dec. 2017) King-Devick Test identifies real-time concussion and asymptomatic concussion in youth athletes. Neurol Clin Pract 2017; 7(6): 464-73.
King-Devick Technologies, Inc. https://kingdevicktest.com/research/concussions/