Performance Times for the King-Devick Test in Children and Adolescents

Objective: To establish the King-Devick test (KD) performance values for children and adolescents. Design: Prospective cohort. Setting: Pediatric sports medicine clinics. Participants: Five hundred seven athletes presenting to a pediatric sports medicine clinic for non-concussion-related evaluations. Independent Variables: Age, sex, and risk factors for abnormal concussion recovery. Main Outcome Measures: The King-Devick test time. Results: Four hundred eighty-three participants were included in the final analysis, which included 60.5% girls (n = 292) and 39.5% boys (n = 191). The KD test performance varied by age with a steady decrease in test time yearly from 8 years through 14 years of age, where some plateauing occurred. Baseline scores changed approximately 31 seconds over ages 8 to 18. Analysis of variance results revealed a strong effect of age on overall mean KD time(P < 0.001). The KD test performance was not associated with sex or other studied concussion risk factors or comorbid conditions. Conclusions: The KD test performance was reported in a cohort of youth aged 8 to 18 years, allowing for comparison of performance in individuals who may not have a baseline assessment. If baseline testing is desired, at least yearly intervals seems to be appropriate through childhood and early adolescence.