A 40-year-old male presented with rapidly progressive dementia for 3 weeks along with rigidity, mask-like facies and mild choreoathetoid movements along with fatigue, sleep disturbance, weight loss, headache, anxiety, veigo, malaise, and ill-defined pain. There is no history of fever. O/E, Visual disturbances Cerebellar disturbances Myoclonus CSF revealed nothing except that there was increase in 14-14-3 protein. CSF revealed nothing except that there was increase in 14-14-3 protein. MRI EEG STUDY