Executive Dysfunction after a Sport-Related Concussion Is Independent of Task-Based Symptom Burden.

Abstract

A sport-related concussion (SRC) results in short- and long-term deficits in oculomotor control; however, it is unclear whether this change reflects executive dysfunction and/or a performance decrement caused by an increase in task-based symptom burden. Here, individuals with a SRC - and age- and sex-matched controls - completed an antisaccade task (i.e., saccade mirror-symmetrical to a target) during the early (initial assessment ≤12 days) and later (follow-up assessment <30 days) stages of recovery. Antisaccades were used because they require top-down executive control and exhibit performance decrements following an SRC. Reaction time (RT) and directional errors were included with pupillometry, because pupil size in the antisaccade task has been shown to provide a neural proxy for executive control. In addition, the Sport-Concussion Assessment Tool (SCAT-5) symptom checklist was completed prior to and after each oculomotor assessment to identify a possible task-based increase in symptomology. The SRC group yielded longer initial assessment RTs, more directional errors, and larger task-evoked pupil dilations (TEPD) than the control group. At the follow-up assessment, RTs for the SRC and control group did not reliably differ; however, the former demonstrated more directional errors and larger TEPDs. SCAT-5 symptom severity scores did not vary from the pre- to post-oculomotor evaluation for either initial or follow-up assessments. Accordingly, an SRC imparts a persistent executive dysfunction to oculomotor planning independent of a task-based increase in symptom burden. These findings evince that antisaccades serve as an effective tool to identify subtle executive deficits during the early and later stages of SRC recovery.