[1] Bristol Royal Hosp Children, Dept Paediat Neurol, Bristol, Avon, England
[2] UCL Inst Child Hlth, Neurosci Unit, London, England
[3] Univ Hosp Southampton NHS Trust, Dept Child Hlth, Southampton, Hants, England
[4] St George Hosp, Dept Paediat Neurol, London, England
[5] Kings Coll Hosp NHS Fdn Trust, Dept Paediat Neurol, London, England
[6] Evelina Childrens Hosp, Dept Paediat Neurosci, London, England
[7] John Radcliffe Hosp, Dept Paediat Neurol, Oxford OX3 9DU, England
[8] Addenbrookes Hosp, Dept Paediat Neurol, Cambridge, England
[9] Birmingham Childrens Hosp, Dept Paediat Neurol, Birmingham, W Midlands, England
[10] Univ Bristol, Sch Clin Sci, Bristol, Avon, England