[1] Ann & Robert H Lurie Childrens Hosp Chicago, Dept Rehabil Serv, Chicago, IL 60611 USA
[2] Ann & Robert H Lurie Childrens Hosp Chicago, Div Neurol, Chicago, IL 60611 USA
[3] Northwestern Univ, Weinberg Coll Arts & Sci, Evanston, IL 60208 USA
[4] Northwestern Univ, Feinberg Sch Med, Dept Prevent Med, Div Biostat, Chicago, IL 60611 USA
[5] Northwestern Univ, Feinberg Sch Med, Dept Pediat, Chicago, IL 60611 USA
[6] Northwestern Univ, Feinberg Sch Med, Dept Phys Therapy & Human Movement Sci, Chicago, IL 60611 USA