Interictal Epileptiform Discharges in Partial Epilepsy

Seizures (also termed ictal discharges) represent the critical events and the primary clinical burden of an active epileptic condition. Between seizures, however, the brain of patients with epilepsy generates pathological patterns of activity, called interictal epileptiform discharges (IEDs), that are clearly distinguished from the activity observed during the seizure itself. The correlation between IEDs and ictal discharges in intractable partial epilepsies has been the subject of several studies (for review see refs. 1–4), yet no conclusion regarding the reciprocal relationship and interdependence of IEDs and ictal discharges has been reached to date. Indeed, the existing data findings have led to two opposite views that assign to IEDs either a preventive or a precipitating role in seizure occurrence.