Outcomes trajectories in children with epilepsy : Hypotheses and methodology of a Canadian Longitudinal Observational Study

Background: The impact of childhood epilepsy can only be appreciated by understanding that epilepsy comprises a set of complex neurobehavioral conditions with significant social consequences, and not simply disorders of recurrent seizures. Our objective is to describe the hypotheses and methodology behind a large prospective longitudinal study that is based on a conceptual framework for understanding health outcomes. The study will quantify the specific influences—direct, mediating or moderating—that various epilepsy, comorbid, child, and family variables exert on health over the early life course. Methods: The target population is 8- to 14-year-old children with epilepsy and their caregivers from across Canada. Children, caregivers, and health professionals are completing 17 measures at five visits over a 28-month period. We have selected measures based on content, the source of the items, psychometric properties, and provisions for child self-report. Our cross-sectional and longitudinal design includes a relational model for structural equation modeling of specific biomedical and psychosocial variables with hierarchical direction of influence. To measure change over time, we will use hierarchical linear modeling. Significance: This article reports the framework for interpreting future data. We believe that it will help researchers consider their methodology and encourage them to plan and execute longitudinal studies. Furthermore, the article will help clinical readers identify what to look for when evaluating outcomes research. It is our belief that the next generation of research to understand life-course effect in the lives of children and youth with chronic conditions and their families must occur over real time.