Transient Epileptic Amnesia over twenty years: Long-term follow-up of a case series with three detailed reports
This is the author accepted manuscript, made available under the CC-BY-NC-ND licence. The final version is available from Elsevier via the DOI in this record.
Reason for embargo
Purpose: Transient Epileptic Amnesia (TEA) is a form of adult onset temporal lobe epilepsy characterised by ictal amnesia. The amnesic seizures are often accompanied by interical memory disturbance, involving autobiographical amnesia and accelerated long-term forgetting. Short-term follow-up studies suggest a relatively stable cognitive profile once treated, but recent case reports raise concerns regarding the risk of developing Alzheimer’s Disease (AD). The current study reports clinical and cognitive outcome in TEA patients over a 20-year period. Methods: A cohort of ten TEA patients first reported in 1998 were followed up at two time intervals, each 10 years apart. Information regarding clinical outcomes and subjective reports of memory functioning was gained via GP records and clinical interview. Objective: memory function was determined at each time point via a comprehensive neuropsychological assessment, where possible. Results: Information was obtained for nine of the original 10 participants. Over the 20-year period, 4 participants died, with no indication of dementia prior to death. One participant was diagnosed with Vascular Dementia. Seizures were generally well controlled. Subjective reports of memory varied, including no concerns, stable memory difficulties, and worsening memory. Neuropsychological assessment at 10 years showed stable performances across most measures. At the 20-year follow up, there was no evidence of a general cognitive decline. Participants showed stability on some measures, with reductions on others. Performance was not consistent with AD. Conclusions: No elevated risk of dementia was evident from this TEA series. Although memory difficulties persist over time, the prognosis of TEA appears generally benign.
This research was supported by The Dunhill Medical Trust [grant number R322/1113]. Associate Professor Chris Butler was funded by an MRC Clinician Scientist award [MR/K010395/1]. Professor John Hodges was supported by funding to Forefront, a collaborative research group dedicated to the study of frontotemporal dementia and motor neurone disease, from the National Health and Medical research Council of Australia program grant [grant number 1037746] and the Australian Research Council Centre of Excellence in Cognition and its Disorders Memory Program [grant number CE110001021].
Vol. 43, pp. 48-55