[1] Univ Turku, Pediat Neurol, Virmuntie 26 As 17, Turku 20540, Finland
[2] Turku Univ Hosp Turku, Virmuntie 26 As 17, Turku 20540, Finland
[3] Turku City Welf Div, Neuropaediat Unit, Turku, Finland
[4] Univ Helsinki, Childrens Hosp, Pediat Neurol, Helsinki, Finland
[5] Helsinki Univ Hosp, Helsinki, Finland