Epileptic amnesic syndrome: an update and further considerations

We describe 30 patients with "epileptic amnesic syndrome" (EAS) with adult-senile onset of a severe memory complaint that started before or at the same time as stereotyped seizures with only short loss of contact and automatisms. Because the seizures were not obvious or disturbing, they remained undiagnosed for a long time. Twenty-three patients also had attacks of transient anteroretrograde amnesia after the seizures: "epileptic amnesic attacks" (EAA). These are similar to attacks of transient global amnesia but are more frequent, shorter, accompanied by clear-cut clinical epileptic manifestations, and respond favorably to antiepileptic drug (AED) therapy. Interictal neuropsychological investigation ruled out global mental deterioration, showing only selective memory impairment in a few long-term tasks, and subjective and objective improvement after AED. Bilateral deep discharges involving the hippocampal-mesial temporal lobe regions may explain EAA, which is probably a postictal phenomenon. The interictal memory problems may be due to subclinical discharges causing difficulty in codification or consolidation of the amnesic trace. EAS patients having uniform anamnestic, clinical and neuropsychological features represent a particular type of temporal lobe epilepsy. We propose a definition of EAS, according to which cases can be classified as definite, probable or possible forms.