The relationship between visually evoked effects and concussion in youth

Abstract

Increased sensitivity to light is common following concussion. Viewing a flickering light can also produce uncomfortable somatic sensations like nausea or headache. Here we examined effects evoked by viewing a patterned, flickering screen in a cohort of 81 uninjured youth athletes and 84 youth with concussion. We used exploratory factor analysis and identified two primary dimensions of variation: the presence or absence of visually evoked effects, and variation in the tendency to manifest effects that localized to the eyes (e.g., eye watering), versus more generalized neurologic symptoms (e.g., headache). Based on these two primary dimensions, we grouped participants into three categories of evoked symptomatology: no effects, eye-predominant effects, and brain-predominant effects. A similar proportion of participants reported eye-predominant effects in the uninjured (33.3%) and concussion (32.1%) groups. By contrast, participants who experienced brain-predominant effects were almost entirely from the concussion group (1.2% of uninjured, 35.7% of concussed). The presence of brain-predominant effects was associated with a higher concussion symptom burden and reduced performance on visio-vestibular tasks. Our findings indicate that the experience of negative constitutional, somatic sensations in response to a dynamic visual stimulus is a salient marker of concussion and is indicative of more severe concussion symptomatology. We speculate that differences in visually evoked effects reflect varying levels of activation of the trigeminal nociceptive system.