Sports-related concussions are an increasingly recognized public health problem and may have serious neurologic implications for athletes. The vision-based King-Devick (K-D) test of rapid number naming has become an important tool to screen for concussion in athletes on the sidelines. In recent years there has been a shift towards using a computerized tablet version of the K-D and although there are several studies demonstrating its utility in screening for concussion, there is limited data directly comparing the two versions. Therefore, the purpose of this investigation was to measure levels of agreement and quantify the relative differences in baseline scores between the spiral-bound and computerized tablet versions of the K-D test. We recruited 85 participants into the study and administered both K-D test versions to each participant. There was excellent agreement (ICC=0.92, 95% CI: 0.82, 0.96) and strong linear correlation(r=0.94) between the two versions. However, the tablet version had a significantly longer mean pre-season baseline time compared to the spiral version (52.3 seconds vs. 48.6 seconds, p<0.001, paired t-test). A difference of 3.7 seconds between the two test modalities may be clinically significant since acutely concussed athletes in published studies and meta-analyses show average increases of 4 to 6 seconds in the K-D test time from baseline. Therefore, the two K-D test versions have excellent agreement suggesting that the tablet version should also be good predictor of concussion. However, alternating between the tablet and spiral versions of the K-D test may be inaccurate when screening for concussion during sideline testing.

Summary Points:

  • The tablet and spiral bound K-D Test showed excellent agreement.
  • The tablet version of the K-D Test is good predictor of concussion.

Users should not alternate between tablet and spiral versions of the K-D test.

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