Introduction

Status epilepticus may be classified for practical purposes into convulsive status epilepticus, which must be rapidly stopped to prevent death or neurologic sequelae, and nonconvulsive status epilepticus (NCSE), in which the diagnosis is not obvious and must be confirmed by urgent electroencephalography (EEG). NCSE may be further classified into nonconfusional and confusional forms (100, 183). Nonconfusional NCSE is characterized by various somatosensory, visual, auditory, psychic, or vegetative symptoms that by definition occur without any impairment of consciousness. Confusional NCSE, by contrast, is characterized by some degree of clouding of consciousness. NCSEs are classically also divided on the basis of the ictal EEG into absence status epilepticus (ASE) and complex partial status epilepticus (CPSE). CPSE is characterized by continuous or rapidly recurring complex partial seizures that may involve temporal or extratemporal regions, or both (see Thomas et al., Chapter 7, this volume). ASE is the most frequent form of NCSE and often constitutes a diagnostic challenge. By definition, it is accompanied by predominantly symmetric synchronous ictal discharges and has heterogeneous clinical and EEG manifestations.