In situ use of the King-Devick eye tracking test and changes seen with sport-related concussion: saccadic and blinks counts

<p><b>Objectives:</b> Sport-related concussion (SRC) can result in impaired oculomotor function. Oculomotor performance, measured utilizing the King-Devick/Eye Tracking test (K-D/ET), is reported to be able to identify sub-optimal brain function. The objectives of the study were to determine the diagnostic accuracy of the K-D/ET in identifying SRC occurring from game participation and to perform a comparative analysis on saccade and blink counts for each K-D card individually and total counts between baseline and post-concussion.<br/><b>Methods:</b> Nineteen male Australian Football players were assessed on the K-D/ET test. Those suspected of having SRC secondary to a head impact were also tested.</br><br/><b>Results:</b> Participants recorded a slower time on the third (20.2 ± 4.6 s) screen when compared with the first (<i>p</i> = 0.0424) and second (<i>p</i> = 0.0150) screens. The number of blinks was higher on the third (2.9 ± 2.9) when compared with the second (<i>p</i> = 0.0057) screen. There was decrease of the K-D/ET total times between pre- and post-game (<i>p</i> = 0.1769). Participants who sustained a head impact recorded slower mean total K-D time (<i>p</i> = 0.7322), fewer mean total saccades (<i>p</i> = 0.0112), and more mean blinks (<i>p </i>= 0.8678) compared with their baseline scores. The assessment of blinks was the most sensitive measure for potential SRC (0.67). The K-D/ET duration was the most specific measure for potential SRC (0.88). An increase in the number of blinks had a fair specificity of 0.69. </br><br/><b>Conclusion:</b> The rapid number-naming component of the K-D test is an assessment tool which quantifies impairment to oculomotor function and has been validated as a diagnostic tool for SRC. The clinical usefulness of the eye tracking component of the K-D/ET test is that it may be an effective method to assess concussions with the eye tracking component serving as a measure of progression and return to play. However, more research is required at the adult and youth level.</br></p>