This is a single-blind study to evaluate the safety and efficacy of Vyvanse™ and provide pilot data in two areas: (1) on the use of Near-Infrared Spectroscopy to detect medication effects in children with ADHD; and (2) on the influence of Vyvanse ™ on reading fluency and comprehension over a period of approximately 6 weeks. Subjects will be between the ages of 6 and 12 at the beginning of the study.