A 50 year old man presents immediately after a left sided focal seizure which lasted for 10 minutes.

He complains of feeling lethargic recently, and of having a 'mild flu'. He also experienced a mild headache a few hours prior to the onset of the seizure.

There is no history of head trauma, while his medical and family histories are unremarkable. He only drinks socially. There is no history of recent foreign travel or contact with animals.

A full blood count, serum electrolyte assay and arterial blood gas assay are normal.