Sleep in Epilepsy Special Interest Group | Brain Flow Dynamics and Sleep Alterations Effect on EpilepsyFrom Babies to Late Adults and Breathing to Cognition: The Impact of Sleep on Seizures and Cognitive Function in Epilepsy Through the Lens of Water

Decades of research have demonstrated the complex intersection between sleep and epilepsy, which significantly impacts seizure control and epilepsy-related comorbidities. However, further investigation is needed to understand the underlying mechanisms linking sleep and epilepsy. Brain exchanges are dynamic processes that include blood-to-brain transport across the blood-brain barrier (BBB), where metabolism is regulated to sustain neural activity, and brain-to-blood and cerebrospinal fluid clearance via the glymphatic system. Together, the BBB and glymphatic system maintain brain milieu homeostasis, and dysfunction at any level can contribute to neurological disorders, including epilepsy. This review highlights the dynamics of water flow within the brain and explores the interrelationship between exchange and clearance pathways across the lifespan, as presented at the 2025 American Epilepsy Society Sleep and Epilepsy Special Interest Group Session. We provide an overview of (1) sleep-related breathing disturbances, their effects on seizures and cognitive function throughout the lifespan, and their implications for sudden unexpected death in epilepsy; and (2) the role of water dynamics mediated by the BBB and the glymphatic system in modulating sleep and epilepsy. These insights deepen our understanding of epilepsy severity and the role of sleep in modifying disease progression, offering promising directions for future research to advance therapeutic strategies.