Status epilepticus as a system disturbance: Is status epilepticus due to synchronization or desynchronization?

Authors


Address correspondence to Sydney S. Cash, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, WACC 730, 55 Fruit Street, Boston, MA 02114, U.S.A. E-mail: scash@partners.org

Summary

The traditional view of seizure activity is one in which there is extreme hypersynchronization. Although what is meant by hypersynchronization is rarely explicitly and fully defined, it can be understood to imply large numbers of neurons firing together essentially simultaneously. In this discussion we explore the possibility that seizures—both self-terminating and sustained in status—are not purely synchronous in time or in space. We investigate the alternative possibility that much seizure activity represents spatiotemporal desynchronization. Furthermore, we discuss the possibility that, in contrast to canonical views of epileptic activity, a high degree of synchronization is a prerequisite for termination of the seizure rather than a marker of early and ongoing seizure activity. These ideas will be discussed with reference to results from our collaborative group based on microelectrode recordings in patients with epilepsy as well as to the many studies done by others in both patients and animal models. Finally, we will explore implications for these hypotheses in the treatment of patients with epilepsy and in status epilepticus.

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