[1] Royal Childrens Hosp, Dept Orthopaed, 50 Flemington Rd, Parkville, Vic 3052, Australia
[2] Royal Childrens Hosp, Murdoch Childrens Res Inst, Parkville, Vic, Australia
[3] Univ Melbourne, Royal Childrens Hosp, Dept Paediat, Melbourne, Vic 3010, Australia
[4] McMaster Univ, CanChild Ctr, Hamilton, ON, Canada
[5] Michigan State Univ, Coll Human Med, Dept Epidemiol, E Lansing, MI 48824 USA
[6] Michigan State Univ, Coll Human Med, Dept Biostat, E Lansing, MI 48824 USA
[7] Michigan State Univ, Coll Human Med, Dept Pediat & Human Dev, E Lansing, MI 48824 USA
[8] Univ Libre Bruxelles, Dept Neurol, Brussels, Belgium
[9] Evelina Childrens Hosp, Complex Motor Disorders Serv, London, England
[10] NIH, Dept Rehabil Med, Bethesda, MD 20892 USA
[11] Vrije Univ Amsterdam, Med Ctr, Dept Rehabil Med, Amsterdam, Netherlands
[12] Rehabil Inst Chicago, Feinberg Northwestern Sch Med, Dept Phys Med & Rehabil & Pediat, Chicago, IL 60611 USA
[13] Newcastle Univ, Inst Hlth & Soc, Newcastle Upon Tyne, Tyne & Wear, England
[14] Royal Childrens Hosp, Murdoch Childrens Res Inst, Dev Disabil & Rehabil Res, Parkville, Vic, Australia
[15] Rehabil Inst Chicago, Chicago, IL 60611 USA