On the relationships between epilepsy, sleep, and Alzheimer’s disease: A narrative review

•Epilepsy, sleep, and Alzheimer’s disease are tightly interconnected.•Epileptiform activity and sleep disorders are both highly prevalent in Alzheimer’s disease.•The treatment of modifiable risk factors such as epilepsy and sleep disturbances is important in Alzheimer’s disease.•Slow-wave sleep is essential for memory consolidation and might present a therapeutical target in Alzheimer’s disease.•Enhancement of slow-wave sleep must take into consideration the possible increase of epileptiform activity. Epilepsy, sleep, and Alzheimer’s disease (AD) are tightly and potentially causally interconnected. The aim of our review was to investigate current research directions on these relationships. Our hope is that they may indicate preventive measures and new treatment options for early neurodegeneration. We included articles that assessed all three topics and were published during the last ten years. We found that this literature corroborates connections on various pathophysiological levels, including sleep-stage-related epileptiform activity in AD, the negative consequences of different sleep disorders on epilepsy and cognition, common biochemical pathways as well as network dysfunctions. Here we provide a detailed overview of these topics and we discuss promising diagnostic and therapeutic consequences.