[1] Addenbrookes Hosp, Dept Clin Neurosci, Div Neurosurg, Cambridge, England
[2] Univ Cambridge, Cambridge, England
[3] Natl Hosp Neurol & Neurosurg, Dept Neurosurg, Queen Sq, London W1CN 3BG, England
[4] UCL, Wellcome EPSRC Ctr Intervent & Surg Sci, London, England
[5] Royal London Hosp, Dept Neurosurg, London, England
[6] Univ Cambridge, Clin Sch Med, Cambridge, England
[7] Inst Metab Sci, Metab Res Labs, Cambridge, England
[8] Univ Cambridge, Dept Med, Cambridge, England
[9] Addenbrookes Hosp, Cambridge, England
[10] Addenbrookes Hosp, Dept Otolaryngol, Cambridge, England