[1] Childrens Natl Hlth Syst, Div Neuropsychol, Washington, DC 20010 USA
[2] George Washington Univ, Sch Med, Dept Psychiat & Behav Sci, Washington, DC USA
[3] George Washington Univ, Sch Med, Dept Pediat, Washington, DC 20052 USA
[4] Childrens Natl Hlth Syst, Biostat, Washington, DC USA
[5] George Washington Univ, Epidemiol & Biostat, Washington, DC USA
[6] Childrens Natl Hlth Syst, Div Cardiol, Washington, DC USA