Sports Medicine Research: In the Lab & In the Field: Don’t Blink. The King-Devick Test: A Rapid, Sideline Visual Assessment Tool to Assist in Detection of Concussion (Sports Med Res)


Monday, March 16, 2015

Don’t Blink. The King-Devick Test: A Rapid, Sideline Visual Assessment Tool to Assist in Detection of Concussion

The King-Devick test for sideline concussion screening in collegiate football

Leong DF, Balcer LJ, Galetta SL, Evans G, Gimre M, Watt D. Journal of Optometry. 2015. doi: 10.1016/j.optom.2014.12.005. [Epub]

Take Home Message: The King-Devick test is a quick and reliable method to assess vision, eye movements, language function, and attention. An athlete with a concussion tends to complete the test slower than his/her preseason assessment while other athletes improve over time. 

With recent attention on the potential consequences associated with concussions there has been an emphasis on rapid and accurate diagnosis of concussions.  This will aid in removal from activity to assist recovery and hopefully prevent athletes from sustaining further head trauma.  The purpose of this article was to assess the validity of the King-Devick test as a sideline concussion assessment among collegiate athletes. 127 student-athletes (football, men’s and women’s basketball) with a mean age of ~20 years participated in this study.  Participants completed a baseline King-Devick test during preseason physicals.  The test takes two minutes and requires an athlete to quickly read a series of numbers on three test cards. If an athlete sustained a concussion then he/she completed the King-Devick test and Sport Concussion Assessment Tool 2 (SCAT-2) immediately on the sideline. Non-concussed participants completed post-season testing to compare to the baseline results in order to assess performance changes and reliability over the season.  Basketball players also completed the test immediately after an intense sprint workout to see how the test was affected by exercise. During the course of the season 11 athletes sustained a concussion and 9 failed their sideline SCAT-2 test. The authors found that individuals who suffered a concussion took longer to complete the King-Devick test compared with their baseline measurements.  On average concussed participants took 4.4 seconds longer compared with their baseline times.  In contrast, participants without a concussion were slightly faster during post-season testing, which may indicate a learning effect. The test had excellent retest reliability from baseline to post-season in non-concussed participants.  The post-workout results were similar to the post-season results, which indicated that fatigue did not influence the test times.

The King-Devick test appears to be a valid and reliable assessment for concussions among college athletes.  The King-Devick tests’ portability and simplistic approach makes it an ideal sideline assessment for detecting changes in quick eye movements and saccades observed in individuals suffering from head trauma. Although the King-Devick test seems to be an effective method to assess concussions, it is not clear yet if it can serve as a standalone evaluation.  Multiple measures may be ideal to gain a complete picture of an individual athlete's symptoms and deficits.  Considering there are limited studies on the King-Devick test, more research needs to be completed to assess its’ effectiveness to assist clinicians for rehabilitation purposes and return-to-play decisions. It is important to note that this study had a small number of athletes with concussions, which limits our ability to apply these results to other collegiate athletes and limited the authors’ ability to suggest clinically relevant cut-points that may differentiate athletes with or without a concussion.  Despite these limitations, this is another tool sports medicine professionals may use on the sidelines to assist in the rapid detection of concussions.

Questions for Discussion: What sideline assessments do you use for concussions? Which do you think are the most effective? Have you tried using the King-Devick test?

Written by: Adam Rosen and Andrew Sheridan
Reviewed by: Jeffrey Driban

Related Post:

Leong, D., Balcer, L., Galetta, S., Evans, G., Gimre, M., & Watt, D. (2015). The King–Devick test for sideline concussion screening in collegiate football Journal of Optometry DOI: 10.1016/j.optom.2014.12.005


Kaitlyn Grossman ATC said...

Really interesting article!

I am excited to hear that the King-Devick test is a reliable measure for evaluating concussion. As in this article, I also use the SCAT 2 in concussion assessment. While the SCAT 2 assess lower extremity coordination, I think it also important to look at eye coordination. The eyes will often overshoot if you look at them closely in concussed athletes. It is something the athlete can absolutely not lie about, as my team physician taught me, "the eyes can't lie".

I think the best concussion evaluation is a comprehensive one, assessing all impairments concussion can cause. I think the King-Devick showed that it can be another tool in the tool box. It is definitely administered faster than the SCAT 2, but is not as comprehensive.

I have tried the King-Devick test myself. It is quite difficult to do. I once tried it against someone who was concussed and she got a better score then me. Just as a SCAT 2, I think baseline scores are important if an ATC decides to implement the use of the King-Devick.

Kaitlyn Grossman ATC

Adam Rosen said...

Kaitlyn, thanks for the comment. Baseline scores are absolutely necessary for the King-Devick test to be reliable. It’s quick and easy and may only add 2 minutes or so to your preseason screening, which is obviously beneficial when performing on a large number of athletes at once. As you point out is another tool in the toolbox and should just be one of many items to take into consideration after an athlete suffers a concussion. Do you use any other tests besides the SCAT2 during your concussion evaluations?

Mikayla Rosencrans said...

With recently popularity in concussion research and prevention, I have read several articles focusing on baseline concussion testing, preventative measures, sideline assessment, diagnosis, and return to play protocol. More specifically related to sideline concussion assessment, there has been many tools to examine an athlete when you may think they have a concussion. Unfortunately, a majority of these tools tend to be costly and therefore almost useless in a financially restricted setting. The King-Devick test is a very interesting article and I think that it could be very useful as an effective sideless concussion assessment, beside SCAT.

We use the SCAT3 and BESS testing in sideline concussion assessment, followed by an ImPACT test for return to play. I think the King-Devick test could be found a quick and effective tool for eye coordination and full assessment.

I have looked up the King-Devick test and look forward to trying it out experimentally in the athletic training room. Additionally, I’m excited to read more about the King-Devick test in upcoming research and potentially utilizing it as a sideline tool myself in the future.

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