Epilepsy and dementia, a bidirectional relationship?

Introduction: Epilepsy is one of the most common brain conditions, which affects over 70 million people worldwide, with a higher risk for people over the age of 70. In the other hand, dementia prevalence is up to 7% of individuals above the age of 65 years, and concerns 55 million people worldwide. Several studies were conducted to pursue causal relationship or bidirectional connection between those two pathologies and one of the latest systemic reviews gathering a numerous studies about this subject was published in 2017. By reviewing the most relevant articles in the literature we aimed to clarify the interconnection between epilepsy and dementia: coincidence due to the highest incidence in the elderly, or bidirectional relationship? We also focused our research on the newest studies about the possible impact of anti-epileptic drugs to improve dementia and vice versa. Methods: Due to the large numbers of articles about epilepsy and dementia, we collected twenty-three studies and reviews from 2014 to 2021 that focused on the relationship between those two pathologies, also some latest publications, especially epidemiological ones, concerning epilepsy and dementia. Results: Dementia is a heterogeneous syndrome that can be caused by numerous neurological and medical conditions. Epilepsy is more frequent in the elderly and is significantly higher in elderly patients with dementia than in elderly patients without dementia, whatever the type of dementia (AD, Lewy Body dementia, FTD,…). Numerous studies show that the high incidence of both diseases is not a coincidence of ageing and shared risk factors (i.e cerebrovascular events) and that the two diseases share common pathophysiological mechanisms. In the future, antiseizure approaches would complement and potentially enhance other strategies for treating AD, including that targeting disease protein aggregation.