Abstract
Eye movements may be used to probe higher-level cognitive processes (i.e., executive functions: EF) that support goal-directed behaviours. Since EFs are related to various aspects of life (i.e., mental/physical health, job success, etc.), eye movements could serve as an indicator for monitoring the progression of outcomes related to disease and rehabilitation in clinical populations. Concussion, a mild traumatic brain injury, is associated with subtle neurocognitive deficits that hinder an individual’s real-life performance (i.e., work, school, etc.) long after their clinical symptoms have resolved. Previous work with healthy adults has shown that distinct patterns of gaze behaviour are associated with increased planning and working memory demands. We expand on this work by characterizing gaze behaviour in asymptomatic adults with a history of concussion (>6 months prior) using a challenging problem-solving task (i.e., Tower of London: TOL). Six participants completed the TOL task and gaze was recorded across 28 trials of increasing task difficulty. Our results demonstrated that as task difficulty increased, performance accuracy decreased, while the initial planning and execution movement times increased (ps<0.001). A gaze bias was demonstrated toward the work-space (~60%) during the initial planning and execution intervals (ps<0.002). Notably, participants with concussion did not show the well-documented task difficulty-dependent increase in work-space dwell time. Gaze transition entropy (GTE) (i.e., scan path complexity) increased as a function of task difficulty during the planning (p=0.001) and execution stages (p=0.015). Moreover, GTE was significantly higher in the concussed group when compared to a previous study with healthy adults. As such, our findings provide evidence that asymptomatic individuals with a history of concussion engage in alternative, less efficient planning and problem-solving strategies when performing the TOL task. These strategies allow them to perform the task well when the difficulty level is low-moderate, but performance deficits become apparent in more difficult task conditions.