Remote memory deficits in transient epileptic amnesia [Abstract]

Aims: Transient epileptic amnesia (TEA) is a recently recognised form of temporal lobe epilepsy in which sufferers often complain of irretrievable loss of remote memories. We aimed to answer the following questions: 1) What is the extent and nature of the autobiographical memory loss? 2) Is there impairment of personal semantic and public semantic memory? 3) Is there evidence for focal retrograde amnesia? Methods: 14 patients with TEA and 12 matched controls participated. We used a broad range of standard anterograde and remote memory tests to clarify the extent and nature of the remote memory deficits. In particular, we used the Autobiographical Interview (AI), which provides a more sensitive measure of autobiographical memory than previous instruments, together with tests measuring personal semantic and public semantic memory. Results: Performance on standard tests of anterograde memory was normal. In contrast, there was a severe impairment of memory for autobiographical events, extending across the entire lifespan, providing evidence for the occurrence of “focal retrograde amnesia” in TEA. There was a milder impairment of personal semantic memory, most pronounced for midlife years. There were minor deficits of public semantic memory for recent decades. Conclusions: These results may reflect subtle structural pathology in the medial temporal lobes or the effects of the propagation of epileptiform activity through the network of brain regions responsible for long-term memory