Electroencephalographic assessment of patients with epileptic seizures

This article reviews the role of EEG in the diagnosis and management of patients with epilepsies. We review the morphologic and behavioral characteristics of the interictal and ictal EEG markers of the different types of epilepsy that should guide recording strategies to augment its diagnostic yield, and we attempt to delineate those particular features that may be relevant to the main epilepsy syndromes. Particular emphasis is placed on the activation methods, including hyperventilation, sleep deprivation and sleep, and specific triggers, as well as how these may differ between idiopathic and cryptogenic/symptomatic generalized and focal epilepsies, commenting on possible diagnostic pitfalls and areas of uncertainty. We also consider the indications for long-term recordings (video--telemetry and ambulatory) and emphasize the diagnostic value of polygraphic recordings.