The background EEG is normal. Focal slowing may occur but should not be persistent in one area.
CAUTION Diffuse slowing of
the EEG background
consider other epilepsy syndromes.
CAUTION Persistent focal
slowing in one area
consider structural brain abnormality.
Interictal EEG is typically normal.
CAUTION Focal spikes
shifting from one region to another in sequential EEGs
consider
epilepsy of infancy with migrating focal seizures.
A variant with midline spikes during slow sleep has been described.
Seizures are accompanied by focal discharges and may spread to both hemispheres, if this occurs the ictal discharge often ends in the contralateral hemisphere to the side of seizure onset. The seizure onset may vary from lobe to lobe or from hemisphere to hemisphere in different seizures in the same patient.