Epilepsy and sleep.

PURPOSE OF REVIEW There is a complex relationship between epilepsy, sleep and sleep disorders. Recent studies have provided new insights into the links between the disorders that may facilitate differential diagnosis and treatment but may also improve our understanding of underlying pathophysiological mechanisms. RECENT FINDINGS Sleep and sleep deprivation have long been recognized to influence interictal epileptiform discharges and seizures. More recent studies have shown that primary sleep disorders such as obstructive sleep apnoea may worsen epilepsy and treatment of these sleep disorders can lead to improved seizure control. Seizures may interfere with night-time sleep structure and cause excessive day-time somnolence (EDS). Antiepileptic drugs may also cause EDS or influence sleep. Despite more frequent use of video-electroencephalographic telemetry and polysomnography, the differential diagnostic challenges between nonrapid eye movement parasomnia and nocturnal frontal lobe epilepsy remain. There is also ongoing debate regarding the possibility of a common pathogenic background for parasomnias and nocturnal seizures that is summarized in the review. SUMMARY Accurate identification and diagnosis of sleep disorders as well as epilepsy is clinically important to ensure optimal treatment of both epilepsy and sleep disorders. Further studies of these nocturnal events may advance our understanding of underlying pathological mechanisms and the complex relationship between sleep and epilepsy.