[1] Newcastle Univ, Neurosurg Trials Unit, STICH Off, Newcastle Upon Tyne NE2 4AE, Tyne & Wear, England
[2] Univ Edinburgh, Sch Med, Ctr Populat Hlth Sci, Edinburgh EH8 9AG, Midlothian, Scotland
[3] Newcastle Upon Tyne Hosp NHS Fdn Trust, Royal Victoria Infirm, Reg Neurosci Ctr, Newcastle Upon Tyne NE1 4LP, Tyne & Wear, England