WRITTEN EXPRESSION FOLLOWING PEDIATRIC TRAUMATIC BRAIN INJURY IN SCHOOL-AGED CHILDREN
The purpose of this thesis was to investigate the effect of traumatic brain injury on written expression in school-aged children. In particular, the mediating effect of core and supporting processes of written expression on the effect of traumatic brain injury on written expression was explored. Core skills are those that are thought to be specific to written expression, and in particular, the mechanical execution of written language. The core skills assessed in this study were graphomotor speed, fine motor speed and coordination, spelling and writing fluency. Supporting skills are those processes that are not unique to writing but are necessary for completing most cognitive tasks, and are frequently affected by traumatic brain injury. The supporting skills assessed in this study were processing speed, working memory, and sustained and focused attention. The performance of children with traumatic brain injury was compared to a group of children with orthopedic injuries. Principal components analysis was used to elucidate the primary core and supporting components of written expression. Four components were retained: orthographic output, fine motor skills, working memory and vigilance. Consistent with previous literature, children in the head-injured group performed more poorly on the primary outcome measure of written expression, both core components and working memory. There was no difference between groups, however, on vigilance performance. Bootstrap regression analyses revealed that the effect of traumatic brain injury on written expression was significantly mediated by orthographic output. This finding is relevant for intervening on written expression difficulties in children with traumatic brain injury. Emphasizing orthographic output as a part of already well-established written expression interventions may provide added benefit in this population.