Mild traumatic brain injury induces prolonged visual processing deficits in children

Primary objective: To compare the sensitivity to simple and complex visual stimuli of children who have sustained a mild traumatic brain injury (mTBI) to that of matched non-injured children and to determine the evolution of visuo-perceptual performance over time. Research design: A prospective design was used to assess 18 children with mTBI and 18 matched healthy controls (8-16 years of age). Methods and procedures: Sensitivity to static and dynamic forms of simple (first-order) and complex (second-order) stimuli were assessed at 1, 4 and 12 weeks post-injury and at equivalent times for controls. Orientation and direction identification thresholds were measured for all participants for static and dynamic conditions, respectively. In addition, sensitivity to radial optic flow (inward vs outward), a complex motion stimulus, was assessed. Main outcomes and results: Thresholds measured from all complex stimuli were significantly affected for the mTBI children over time whereas no difference in threshold between groups across all testing conditions was found for simple, first-order information. Sensitivity to all complex stimuli was still affected 12 weeks after the injury. Conclusion: These findings suggest that injured children present selective processing deficits for higher-order information and that this deficit persists over relatively long periods. Such measures could be useful to assess children who have sustained mTBI and possibly contribute to identifying potential risks of returning these children to demanding physical activities.