The King-Devick Test and Sports-related Concussion: Study of a Rapid Visual Screening Tool in a Collegiate Cohort

Galetta KM, Brandes LE, Maki K, Dziemianowicz MS, Laudano E, Allen M, Lawler K, Sennett B, Wiebe D, Devick S, Messner LV, Galetta SL, Balcer LJ. J Neurol Sci. 2011 July 22. [Epub ahead of print]

Immediate assessment of a sports-related concussion is critical to help ensure proper treatment and subsequent management in athletes. The use of swift, objective measures is optimal for sideline administration and elimination of subjective biases during initial assessment post impact. Therefore, Galetta et al. longitudinally studied several collegiate teams (i.e., football, men’s and women’s soccer and basketball) using the King-Devick test to determine the effect of concussion on athletes’ ability to rapidly screen a succession of numbers from a set of three test cards. The test objectively evaluates a subject’s visual tracking and saccadic eye movements while s/he reads a sequence of numbers from left to right, as quickly and accurately as possible, from each of the three cards. Scores are derived according to the total time it takes to complete the set of cards. Pre-season and post-season test scores from the 2010-11 season were recorded for the entire cohort of athletes (n=219); post-injury scores were obtained from those athletes who sustained a concussion during the study period (n=10). Pre-season testing was performed in a rowdy locker room setting (since sideline testing was not possible), post-injury testing on the sidelines, and post-season testing in either of the aforementioned environments. Furthermore, athletes from the sprint football and both basketball teams underwent additional testing to obtain pilot data for future research (e.g., men’s basketball: post-exercise King-Devick test). A comparison of King-Devick scores demonstrated that overall, athletes (n=219) scored significantly better post-season than pre-season score (35.1 vs.37.9 sec), indicative of a learning effect. On the other hand, athletes that did sustain a concussion, with the exception of one athlete, scored significantly worse compared to the pre-season score (46.9 vs.37.0 sec). Moreover, as evidenced from the men’s basketball team, in the absence of a concussion intense exercise resulted in better performance when compared to pre-season scores (35.0 vs. 38.6 sec).

Misdiagnosis of a sports-related concussion, which may lead to premature return to play and increased risk for second impact syndrome, is a concern for sports medicine professionals. In addition, the fast-paced nature of collegiate sports warrants an expeditious assessment of all injuries, including concussions. Interestingly, the King-Devick test was able to detect subtle neurological changes in rapid number recall post-injury in a small cohort of collegiate athletes. This, coupled with the simplistic nature of test administration (sideline testing within 2 minutes), makes it an accessible addition to objectively test for concussion. It would be interesting to see if future research results in a similar effect in a larger cohort of concussed athletes across a wider range of sports and age groups, which could potentially allow for broad application of this instrument. Have you used this test previously? Is it any better than other sideline tests? Would you include this instrument into your concussion test battery? What are your thoughts?

Written by: Nieka Bright

Reviewed by: Stephen Thomas