Amnesia of the epileptic aura.

In a prospective study lasting 6 months, we recorded on video 108 seizures with aura of 23 patients in an attempt to evaluate the mechanisms involved in the encoding of memories. In 88 of those seizures, we also recorded an EEG. The percentage of auras remembered decreased significantly with increasing severity of the seizures. The recollection of auras was also significantly dependent on the ictal EEG changes during the aura. Ninety-seven percent of the auras without EEG changes, 94% of the auras with unilateral EEG changes, and 73% of the auras with bilateral EEG changes during the aura were remembered. The spread of the ictal EEG pattern during the aura also showed a significant correlation with the severity of the ensuing seizure. Three patients with bitemporal epilepsy made up a considerable proportion of those who never remembered their aura before secondary generalized tonic-clonic seizures (2 of 3) and of those who had a transient postictal amnesia of their aura (2 of 3). The only patient who failed to remember a previously documented isolated aura also suffered from bitemporal epilepsy. During the second part of the study, we questioned whether information provided during the history could be helpful in defining the type of epilepsy syndrome or localizing the EEG seizure pattern of the 80 patients who had been admitted for presurgical epilepsy diagnosis. Localized (regional, unilateral, and independent left and right lateral) EEG seizure patterns occurred in 82% of the 51 patients with auras in their history as compared with 24% of the 17 patients who did not have auras in their history (p < 0.01).