Variation In King-Devick Performance Time By Primary Language And History Of A Learning Disorder

Abstract

The King Devick (K-D) is a brief screening test for sport-related concussion (SRC) that involves rapid number naming and assesses reaction time, visual-motor function and reading skill. This test has been used to screen athletes for potential SRC by comparing performance on this test with baseline performance. Some authors have recently begun to explore normative data for this test, but little is known about variation in baseline performance time on this test, or how that might affect its utility for SRC detection. PURPOSE: To examine variation in baseline performance time on the K-D test by demographics and medical history. METHODS: We analyzed data from an ongoing prospective cohort study of varsity collegiate athletes sponsored by the National Collegiate Athletic Association and the Department of Defense from 2014-2016. We analyzed first time administration of the K-D only, examining differences in means with 95%CI by demographics and medical history Student’s T-test. RESULTS: We report on first-time administration data from 2331 athletes (20.1 +/-3.4 yrs) at five universities. Performance time did not differ by age. Athletes whose primary language was not English had significantly slower baseline times (44.7 s., 95% CI: 43.0-46.3) than primary English speakers (41.2 s., 95% CI: 40.9-41.5), as did those with history of a learning disorder (45.7 s., 95% CI: 43.7-47.6) compared to those without a learning disorder (41.1 s., 95% CI: 40.8-41.4). Athletes in collision sports had significantly faster performance time (40.7 s., 95% CI: 40.3-41.1) compared to those in non-collision sports (42.4 s., 41.9-42.9). History of prior concussion and attention deficit hyperactivity disorder (ADHD) were not significantly associated with performance time. CONCLUSION: Performance time on the K-D is significantly slower in athletes who have a primary language other than English and those with a history of a learning disorder. These results suggest caution in the use of normative data with this test given significant individual variation. Future studies should explore whether sensitivity of this test for detecting brain injury is affected by these characteristics.