Oculomotor Executive Dysfunction during the Early and Later Stages of Sport-Related Concussion Recovery.

Executive dysfunction represents the most persistent sequela of mild traumatic brain injury. It is, however, largely unclear whether a sport-related concussion similarly contributes to a persistent executive dysfunction even when an athlete has been cleared medically for return to play. Here, individuals with a diagnosis of a sport-related concussion-and their age- and sex-matched controls-completed an oculomotor assessment during the acute and later stages of injury recovery. Prosaccades (i.e., saccade to a target) and executive-related antisaccades (i.e., saccade mirror-symmetrical to a target) were completed: (1) 2-6 days after a concussive event (initial assessment), and (2) 14-20 days after the initial oculomotor assessment when individuals were cleared for return to play (follow-up assessment). At the initial assessment, the concussed group produced antisaccade reaction times (RT) that were 93 ms longer than the control group (p < 0.001), whereas prosaccade RTs did not differ between groups (p = 0.25). At the follow-up assessment, concussed and control groups produced comparable pro- and antisaccade RTs (ps >0.31); however, the former group exhibited a continued increase in directional errors (p < 0.05). That initial assessment antisaccades-but not prosaccades-differed between groups indicates that the acute recovery of a concussion is associated with a selective executive-related oculomotor deficit, and the continued increase in directional errors at the follow-up assessment suggests that such a deficit persists even when an athlete has been cleared medically for return to play. The antisaccade task may therefore serve to assess subtle executive deficits and determine when an athlete may return to play safely.