The study has been extended through November 2008 to to follow a large cohort of pre-adolescent children to determine whether untreated sleep apnea is associated with identifiable decrements in neurocognitive performance and school performance, as well as perturbations of blood pressure and growth, at approximately four years after initial enrollment and identification of sleep apnea. The study also aims to identify pre-adolescent anthropometric and ethnic variables associated with future development and/or regression of sleep apnea .The study secondarily aims to determine whether abnormalities in ventilatory drive found in pre-adolescence in children with sleep apnea persist after approximately four years of untreated sleep apnea.