Impact of Factors that Affect Reading Skill Level on King–Devick Baseline Performance Time

The King–Devick (K–D) test is often used as part of a multimodal assessment to screen for sport-related concussion. However, the test involves reading numbers, and little is known about variation in baseline performance on the K–D by reading skill level. We conducted a cross-sectional study analyzing data from the Concussion Assessment, Research and Education (CARE) Consortium to assess differences in baseline performance on the K–D associated with factors that impact reading skill level (learning disorder [LD] and primary home language other than English [PHLOTE]), while controlling for covariates (gender, type of sport, attentional issues, history of concussion and modality of administration). We had a sample of 2311 student-athletes (47% female), and multivariate regression indicated an average K–D performance time of 40.4 s. Presence of LD was associated with a 3.3 s slower K–D time (95% CI 1.9–4.7, p < 0.001), and PHLOTE was associated with a 2.6 s slower K–D time (95% CI 1.2–4.0, p < 0.001), after controlling for other covariates. These results suggest caution in the use of normative data with the K–D. Future studies should explore the impact of factors associated with reading skill level on sensitivity of the K–D in detecting concussion.