The background EEG is normal.
The interictal EEG is often normal, generalized spike-and-wave or fragments of generalized spike-and-wave may be seen.
EEG abnormality is enhanced by sleep deprivation and by sleep. Generalized spike-and-wave often becomes fragmented with sleep deprivation or in sleep. Fragmented generalized spike-and-wave can appear focal or multi-focal but usually is not consistently seen in one area. The morphology of the focal spike-and-wave typically appears similar to the generalized spike-and-wave.
The ictal EEG varies with the seizure type occurring, refer to individual seizure types for more information.