The epileptic pre-aura.

Abstract

The term "pre-aura" is used for the designation of earliest pre-ictal manifestations that escape detection by conventional EEG and both objective and subjective behavioral signs. Fairly recent reports have indicated earliest pre-ictal vascular changes (perifocal ischemia and hyperemia) and also changes found in various methods of quantified EEG. These changes may precede the seizure onset (in conventional terms) by 1 to 20 minutes. There is good reason to assume that pre-auras are limited to focal epilepsies and do not occur in the various subforms of primary generalized epilepsy. The electrodecremental type of seizure onset, mostly found in the frontal region, could also denote a pre-aura in the earliest decremental phase. The very earliest pre-aura phenomena are most likely to be neuronal rather than vascular. Further proof could come with the use of ultrafast EEG frequency recordings.