Epilepsy and sleep

This review focuses on the interrelation between clinical and electrophysiological manifestations of various epilepsy forms and level of wakefulness or sleep. In case of some epileptic syndromes seizures occur predominantly or solely in sleep. Epilepsy can modify normal sleep patterns; on the other hand, sleep influences interictal epileptiform discharges, increasing their number and changing their morphology and spreading depending on sleep stage. Although interictal discharges in focal epilepsy are more common in sleep than in wakefulness, discharge distribution in generalized epilepsy is more variable. For some epileptic syndromes there is a strong correlation between time of onset, frequency, severity of attacks and stage of sleep cycle or wakefulness. Further research in this area can shed light not only on mechanisms of epileptic networks functioning, but also on the sleep-wake cycle regulatory systems.