[1] Vanderbilt Univ, Sch Med, Dept Neurol, Sleep Disorders Div, 221 Kirkland Hall, Nashville, TN 37235 USA
[2] Univ Colorado, Sch Med, Dept Pediat, Aurora, CO USA
[3] Massachusetts Gen Hosp, Ctr Biostat, Boston, MA 02114 USA
[4] Univ Rochester, Dept Pediat, Rochester, NY USA
[5] Nationwide Childrens Hosp, Dept Pediat, Columbus, OH USA
[6] Childrens Hosp Philadelphia, Dept Pediat, Philadelphia, PA 19104 USA