Prolonged Nonepileptic Twilight State with Convulsive Manifestations After Febrile Convulsions: A Clinical and Electroencephalographic Study

Summary: EEGs were obtained from 14 infants during behavior clinically diagnosed as prolonged febrile seizures. The clinical manifestations during EEG recordings resembled complex partial seizures (CPS) with convulsive manifestations, but the accompanying EEG waveforms were not epileptiform. Rather, two types of slow wave activity occurred: One was continuous diffuse delta (CDD) waves; the other was diffuse rhythmic theta (DRT) waves. I have termed these clinical states “nonepileptic twilight states with convulsive manifestations” (NETC). Because the CDD and DRT activity was similar to childhood arousal responses, I hypothesized that NETC might be a prolonged arousal state with increased muscle tone induced by a preceding febrile convulsion.