[1] Univ Cologne, Dept Neurol, D-50931 Cologne, Germany
[2] Univ Cologne, Dept Paediat, D-50924 Cologne, Germany
[3] Guys & St Thomas NHS Fdn Trust, Evelina Childrens Hosp, London, England
[4] Univ So Calif, Los Angeles, CA USA
[5] Cook Childrens Med Ctr, Ft Worth, TX USA
[6] Univ Rochester, Med Ctr, Rochester, NY 14627 USA