[1] Kennedy Krieger Inst, Maryland Ctr Dev Disabil, 7000 Tudsbury Rd, Baltimore, MD 21244 USA
[2] Nationwide Childrens Hosp, Dev & Behav Pediat, 700 Childrens Dr, Columbus, OH 43205 USA
[3] Vanderbilt Univ, Med Ctr, Dept Neurol, Sleep Disorders Div, A-0118 Med Ctr North, Nashville, TN 37232 USA
[4] Johns Hopkins Univ, Dept Pediat, Sch Med, 1800 Orleans St, Baltimore, MD 21287 USA
[5] Childrens Hosp Philadelphia, Dev & Behav Pediat, 3550 Market St, Philadelphia, PA 19104 USA