Similarity of symptoms between transient epileptic amnesia and Lewy body disease

Epilepsy with the main symptom of amnesia is known as transient epileptic amnesia (TEA). Dementia with Lewy bodies (DLB) is the second most common form of neurodegenerative dementia. The concept that Lewy body disease includes Parkinson's disease with dementia and dementia with Lewy bodies was proposed in the 2005 revision of the Clinical Diagnostic Criteria. Here, we describe a woman with cognitive impairment, olfactory dysfunction, and reduced I-123-meta-iodobenzylguanidine uptake on myocardial scintigraphy. The patient and her family and friends were unaware of parkinsonism, visual hallucinations, or epilepsy for a long period. After syncope occurred twice within a short interval, electroencephalography revealed sharp waves from the bilateral frontal to parietal lobes, indicating a diagnosis of TEA. The present case prompted us to compare the symptoms of TEA with the clinical diagnostic criteria for dementia with Lewy bodies, revealing their similarities. We also discuss whether Lewy body disease may cause TEA rather than having an incidental association with it.