Presentation at the American Academy of Neurology 2017 Annual Meeting

Year to Year Reliability of the King-Devick Test in Collegiate Student-Athletes: An NCAA/DoD Grand Alliance Report

Authors: Buckley T, Breedlove K, Oldham J, Kontos A, DiFabio M, Kaminski T, Clugston J, Schmidt J, Chrisman S, DeWolf R, Ortega J
Publication: Presentation at the American Academy of Neurology 2017 Annual Meeting
Date: April 27, 2017
Tags: Collegiate Athletes,

Objective: To determine the year to year reliability of the King-Devick (KD) test in collegiate student athletes.

Background: The KD test is an emerging assessment for the identification of sports-related concussions and has been incorporated as a “Level B” assessment in the NCAA/DoD Grand Alliance. A subtle improvement of 2-3 seconds is expected in acute repeat administrations; however, the reliability over a year has not been established.

Design/Methods: There were 830 NCAA collegiate student-athletes (Age: 20.2 + 1.3 years old, Height: 180.0 + 11.1cm, Weight: 82.6 + 21.5kg) from five institutions who performed the KD test annually for two years as part of the NCAA/DoD CARE protocol. All participants performed the KD test according to recommended protocols, two trials each year, and tests were performed prior to each participant’s intercollegiate athletic season. The outcome measure of interest was the fastest time without errors each year. A Pearson correlation compared the reliability of the measure and reliable change index (RCI) was calculated.

Results: There was a significant positive correlation between the two years (Year 1: 40.8 + 7.4 seconds and Year 2: 38.75 + 7.7 seconds, r=0.827, p<0.001). The mean improvement was 2.01 seconds, mode was 2.0 seconds, and median improvement was 2.2 seconds. The RCI was 8.47 seconds and 62 participants (7.5%) exceeded the RCI with most (48/62, 77.4%) having a faster score in year 2.

Conclusions: These results suggest that the KD is reliable from year to year and a modest improvement in performance of about 2 seconds should be expected with repeat administration in the second year. Clinicians should not that a small percentage of individual will demonstrate changes exceeding the RCI with repeat administration and future investigations should seek to identify determinants of performance variability.

Study Supported by: NCAA/DoD Grand Alliance: W81XWH-14-2-0151

Summary Points:

  • K-D Test is reliable from year to year with a modest improvement in performance of about 2 seconds with repeat administration.
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