[1] Gloucestershire Royal Hosp, Dept Neurol, Great Western Rd, Gloucester GL1 3NN, England
[2] Univ Oxford, John Radcliffe Hosp, Nuffield Dept Clin Neurosci, Headley Way, Oxford OX3 9DU, England
[3] Eda Mem Hosp, Dept Med, Aoba Ku, Azamino Minami 1-1-1, Yokohama, Kanagawa 2250012, Japan