Group 1 features |
| (a) Progressive neuropsychiatric disorder (depression, anxiety, withdrawal, delusions) |
| (b) Duration of illness > 6 months |
| (c) Routine investigations do not suggest an alternative diagnosis |
| (d) No history of potential iatrogenic exposure |
Group 2 features |
| (a) Early psychiatric symptoms (depression, anxiety, apathy, withdrawal, delusions) |
| (b) Persistent painful sensory symptoms (includes frank pain and/or unpleasant dysaesthesia) |
| (c) Ataxia |
| (d) Myoclonus or chorea or dystonia |
| (e) Dementia |
Group 3 |
| (a) EEG does not show the typical appearance of sporadic CJD (or no EEG performed) |
| (b) Bilateral pulvinar high signal on MRI scan |
Group 4 |
| (a) Positive tonsil biopsy |