To determine if change in King-Devick test (K-D) score from baseline in acutely concussed collegiate Division I athletes predicts time to return to play (RTP).

Efferent visual pathways are vulnerable to impairment during the acute stages of concussion; these pathways can be assessed through visual performance measurements such as the K-D test.  K-D requires rapid eye movements (horizontal saccades), attentional focus, and language function, requiring the integration of the brainstem, cerebral cortex, and the cerebellum.  K-D performance is impaired acutely post-concussion; however, the association between degree of impairment and recovery duration has not been established.

Thirty-one NCAA Division I student-athletes (1.7 + 0.1 m, 69.9 + 12.6 kg, 21 female) performed K-D at baseline (prior to sports participation) and then again within 24-48 hours post-concussion.  A linear regression was modeled with change in K-D score between baseline and acute as the independent variable, and days until RTP as the dependent variable.

Average baseline and post-injury K-D scores were 39.9 + 5.9 and 46.0 + 20.6 s respectively. The average change in K-D score was 6.12 + 18.6 s (range: -7.3-97.3 s) and mean days until RTP was 20.0 +20.4 days (range: 8-119 days).  The overall regression model was not significant for K-D change as a predictor of RTP time, F(1, 29) = .002, p = .961, R² = .00.