Assessment of mild traumatic brain injury with the King-Devick Test® in an emergency department sample

Objective: The King-Devick Test (R) (K-D) is a brief measure of cognitive processing speed and rapid gaze shifting that appears sensitive to the effects of sport-related concussion. This study evaluated its diagnostic and incremental validity in civilian patients with mild traumatic brain injury (MTBI). Methods: Participants with MTBI (n = 26) and controls with non-head injuries (n = 33) were prospectively recruited from an Emergency Department (ED). They underwent a clinical evaluation including the K-D test and the Sport Concussion Assessment Tool 2 (SCAT2). Magnetic resonance imaging (MRI) was conducted within 10 days post-injury. Results: The patients with MTBI differed from those without MTBI on components of the SCAT2, including the Symptom Scale (Cohen's d = 1.02-1.15, p<0.001) and Standardized Assessment of Concussion (d = 0.81, p = 0.004), but not the K-D test (d = 0.40, p = 0.148). In a logistic regression analysis, the K-D Test did not contribute over and above these two measures in predicting group membership (MTBI vs. control), p = 0.191. Low K-D Test scores in the MTBI group (<1 SD below controls) were not associated with poor SCAT2 performance, loss of consciousness or traumatic abnormalities on MRI, suggesting these cases may have been false positives. Conclusions: The present findings do not support the K-D Test for the assessment of civilian MTBI in an ED setting.