[1] Natl CJD Res & Surveillance Unit, Edinburgh, Midlothian, Scotland
[2] Western Gen Hosp, Dept Neurol, Edinburgh EH4 2XU, Midlothian, Scotland
[3] Western Gen Hosp, Dept Neuroradiol, Edinburgh EH4 2XU, Midlothian, Scotland
[4] John Radcliffe Hosp, Nuffield Dept Clin Neurosci, Oxford OX3 9DU, England
[5] Nottingham Univ Hosp NHS Trust, Nottingham, England