Use of the King-Devick test for sideline concussion screening in junior rugby league

Aim: To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion.

Methods: A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation.

Results: The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s).

Discussion: Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation.

Conclusion: The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players.