generalized seizure

Generalized seizures have initial clinical manifestations suggesting involvement of both cerebral hemispheres, with diverse forms that may be convulsive or non-convulsive, often accompanied by impaired consciousness; myoclonic seizures are of short duration and may occur without impairment of consciousness; motor symptoms are often bilateral, but not necessarily generalized, and may also be absent. At seizure onset, EEG shows neuronal discharges that spread widely within both hemispheres. The clinical manifestations of various types of generalized seizures are quite characteristic, and the EEG findings are highly specific but vary considerably; for example, in absence seizures, regardless of differences in clinical presentation, the fundamental EEG change during the seizure is paroxysmal spike-and-slow-wave discharges; in atonic seizures, although the ictal EEG may show various patterns, all have a certain degree of specificity.