Transient global amnesia mimics: Transient epileptic amnesia

Abstract

We describe the case of a 79-year-old patient referred for suspected transient global amnesia, after an episode of anterograde amnesia which lasted 90 min. An EEG, performed after the episode, showed bilateral temporal electrographic seizures, orienting the diagnosis toward a transient epileptic amnesia. Transient epileptic amnesia is defined by temporal lobe epilepsy characterized by recurrent transient amnestic episodes of 30-90 min in duration, sometimes associated with olfactory hallucinations or oral automatisms. Response to antiepileptic drugs is excellent. We would like to raise awareness toward this epileptic amnesia when facing atypical or recurrent transient amnestic episodes.

Keywords: AEDs, antiepileptic drugs; EEG, electroencephalogram; TEA, transient epileptic amnesia; TGA, transient global amnesia; Temporal lobe epilepsy; Transient epileptic amnesia; Transient global amnesia.

Fig. 1

Ictal EEG performed 3 h after the end of the episode. Right temporal lobe electrographic of 25- to 30-second duration. On this longitudinal bipolar montage (double banana), the standard 20-minute duration EEG shows a right temporal electrographic seizure with a recruiting pattern affecting the whole right temporal region. This electrographic seizure was immediately followed by a left temporal electrographic seizure of shorter duration (about 15 s) (data not shown). There were no obvious clinical symptoms, but the patient was not tested during these ictal electrical patterns.