1. Medical Research Council Prion Unit, Department of Neurodegnerative Disease, University College London Institute of Neurology, London, England2National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospitals, NH
2. Department of Statistical Science, Faculty of Mathematical and Physical Sciences, University College London, London, England
3. National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospitals, NHS Trust, London, England
4. Medical Research Council Prion Unit, Department of Neurodegnerative Disease, University College London Institute of Neurology, London, England
5. Division of Neuropathology, National Hospital for Neurology and Neurosurgery, University College London Hospitals, NHS Trust, London, England
6. Division of Neuropathology, National Hospital for Neurology and Neurosurgery, University College London Hospitals, NHS Trust, London, England5Department of Neurodegenerative Disease, University College London Institute of Neurology, London, England
7. MRC Clinical Trials Unit at University College London, London, England