Background

The EEG background may be normal or may show minor non-specific abnormality. During active seizure phases, focal or widespread slowing may be seen.

Interictal

Focal epileptiform abnormalities can be seen in approximately two thirds of cases, most commonly in the central, centrotemporal, or frontotemporal regions.

Ictal

A typical ictal pattern has been described with an initial attenuation of the EEG lasting up to 20 s, followed by repetitive spike discharges (mainly centrotemporal, although other regions can be affected). Discharges are often bilateral but asynchronous and can shift localisation from seizure to seizure.