Considerations of nonconvulsive status epilepticus

The original concepts of absence status (AS) and complex partial status (CPS) are critically reviewed. This review has been prompted by a modern concept of nonconvulsive status epilepticus (NCSE), portrayed as a rather common condition occurring chiefly in the critically ill elderly with high morbidity and mortality. This new view is a striking departure from the original concepts of AS and CPS as rare protracted epileptic events occurring usually in temporarily confused but otherwise satisfactorily healthy and ambulatory patients. This new trend appears to have been caused by a misinterpretation of EEG findings: prominent generalized spike activity is in reality the expression of a very severe encephalopathy rather than of NCSE, most often caused by an anoxic episode. The role of EEG is emphasized but a valuable interpretation depends on an expert integration of EEG and clinical data. A brief discussion of epileptic twilight states further stresses the difficult differential diagnosis.