All partial seizures are characterized by onset in a limited area, or focus, of one cerebral hemisphere. The 1989 International Classification of Epileptic Seizures (ICES) remains the most widely accepted classification system, although several recent modifications of terminology have been proposed.
In all these classifications systems, however, simple partial seizures (SPS) are defined as those that are not associated with any alteration of consciousness.
Although the ability to respond may be preserved, motor manifestations or anxiety relating to the seizure symptoms may prevent a patient from responding appropriately.
The level of consciousness may be difficult to determine during a partial seizure, especially in infants, cognitively impaired individuals, and aphasic patients. The lack of availability of trained persons to interact directly with the patient during and after the seizure can make distinctions between simple and complex partial seizures difficult, even with high-resolution video-EEG.
The ICES defines an aura as “that portion of the seizure which occurs before consciousness is lost, and for which memory is retained afterwards.” Auras without subsequent seizures should be considered a type of SPS.
Simple partial status epilepticus (SPSE) includes epilepsia partialis continua (ie, Kojewnikoff syndrome). Some researchers also have included periodic lateralized epileptiform discharges (PLEDs) and the spectrum of Landau-Kleffner syndrome as types of SPSE.
The suspicion of SPS is based on a history consistent with the typical, reproducible patterns seen with the various SPS categories (see Clinical Presentation). An electroencephalogram (EEG) fortuitously obtained during the patient’s symptoms can provide clear support for a diagnosis. EEGs obtained soon after a suspected seizure often record nonspecific patterns or may be normal (see Workup).
In most patients with SPS, antiepileptic drug therapy is appropriate. Selected patients with SPS refractory to AEDs may be candidates for surgical treatment (see Treatment and Management).
Go to Epilepsy and Seizures for an overview of this subject.