[1] Massachusetts Dept Publ Hlth, Bur Family & Community Hlth, Boston, MA 02116 USA
[2] Boston Univ, Sch Publ Hlth, Dept Maternal & Child Hlth, Boston, MA USA
[3] Beth Israel Deaconess Med Ctr, Dept Neurol, Boston, MA 02215 USA
[4] Harvard Univ, Sch Med, Dept Pediat, Boston, MA 02115 USA
[5] Massachusetts Dept Publ Hlth, Bur Family & Community Hlth, Boston, MA 02108 USA