Electrocorticographic changes during generalized convulsive status epilepticus in soman intoxicated rats.

Generalized convulsive status epilepticus (GCSE) is the most common and potentially most damaging form of status epilepticus (SE). It has been previously reported, in both human GCSE and animal models of GCSE, that the electroencephalographs (EEGs) and electrocorticographs (ECoGs) recorded during GCSE contain an ordered sequence of five identifiable patterns: discrete seizures (phase 1), waxing and waning ictal discharges (phase 2), continuous ictal discharges (phase 3), continuous activity with flat periods (phase 4), and periodic epileptiform discharge on a flat background (phase 5). In this paper, we report the same pattern of ECoG changes in 15 rats exposed to soman, an acetylcholinesterase (AChE) inhibitor. Phase 1 was observed in 12 of 15 animals, but phases 2-5 were recorded in all the animals. Taken together, these findings suggest that the sequence of EEG changes is independent of the initiating cause, represent a common electrical response to GCSE, and reflect a common underlying neurochemical mechanism.