The Physician and SportsMedicine. 2018.

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

Authors: Mark Hecimovich, Doug King, Alasdair Dempsey, Mason Gittins & Myles Murphy, University of Iowa Department of Athletic Training; Murdoch University, School of Psychology and Exercise Science; Auckland University of Technology, Department of Health and Environmental Science; University of New England, Department of Science and Technology; The University of Notre Dame Australia, School of Physiotherapy
Publication: The Physician and SportsMedicine. 2018.
Date: September 26, 2018
Tags: Australian Football,Eye Tracking,Post-Concussion,Youth Athletes,

Objective: 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.

Methods: 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.

Result: Participants recorded a slower time on the third (20.2 ± 4.6 s) screen when compared with the first (p=0.0424) and second (p=0.0150) screens. The number of blinks were higher on the third (2.9 ± 2.9) when compared with the second (p=0.0057) screen. There was decrease of the K-D/ET total times between pre- and post-game (p=0.1769). Participants who sustained a head impact recorded slower mean total K-D time (p=0.7322), fewer mean total saccades (p=0.0112) and more mean blinks (p=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.

Conclusion: 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.

Summary Points:

  • A rapid number-naming task called the King–Devick (K–D) test has been validated as a sensitive sideline performance measure for concussion detection. This test functions as a pseudoreading task, broadly capturing aspects of afferent visual function, attention, language, visual fixation, and saccadic eye movements.
  • The K-D Eye Tracking System (K-D/ET) allows for real-time automated eye movement data and output using measures of fixations, saccades, blinks, and pupillary dynamics. This eye tracking technology brings objective tools to the clinical management of oculomotor dysfunctions while allowing quantifiable measurement of impairment severity and status over progression and remediation.
  • Participants who sustained a head impact recorded slower mean total K-D time (p=0.7322), fewer mean total saccades (p=0.0112) and more mean blinks (p=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.
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