What are the clinical manifestations of spongiform encephalopathies?

1. Creutzfeldt-Jakob disease CJD :85% cases are sporadic; 15% are familial

2.Middle age to elderly patients

3.Rapidly progressing dementia 

4.Memory loss with startle myoclonus or other involuntary movements

5.Typical EEG changes

6.Death within 6-12 months.