[1] Univ London Imperial Coll Sci Technol & Med, Charing Cross Hosp, Dept Neurosurg, London W6 8RF, England
[2] Univ London Imperial Coll Sci Technol & Med, Charing Cross Hosp, Dept Med, London W6 8RF, England
[3] Univ London Imperial Coll Sci Technol & Med, Charing Cross Hosp, Dept Neurol, London W6 8RF, England
[4] Univ London Imperial Coll Sci Technol & Med, Charing Cross Hosp, Dept Radiol, London W6 8RF, England