Figure 2
(A1) Typical interictal background with epoch revealing diffuse attenuation of the background activity with focal polymorphic theta activity over F4> F8 and Fz. Rare surface negative sharp waves are observed over F4>F8. (A2) Rare onset of a non-convulsive seizure characterized by fluctuating 1-Hz sharply contoured lateralized periodic discharges (LPDs) over F4 (most onsets did not feature LPDs), transitioning in the middle of the epoch to low-voltage irregular and arrhythmic fast activity with frequent intermixed low-amplitude positive spikes over F4 (arrow). (A3) Continuation of previous epoch of recording, highlighting an ongoing focal non-convulsive seizure, maximal over F4 and characterized by frequent intermixed surface positive low-amplitude spikes over F4 (arrow). (B) Typical ending of electrographic seizure activity with 1-2-Hz delta activity over F4, F8 (arrow). (C) Typical progression of a non-convulsive seizure viewed in a referential montage with surface positive sharp waves over F4 and F8. HFF: 70 Hz; LFF: 1 Hz ; 10 mm/sec, Notch off.