Over a century of work has confirmed critical links between sleep and epilepsy. Seizures can have profound effects on sleep, typically causing awakenings, arousals and shifts to lighter stages. However, sleep continuity is disrupted in people with epilepsy even in the absence of seizures, suggesting that sleep instability may be an inherent component of certain forms of epilepsy. Antiepileptic drugs (AEDs) can adversely affect sleep and wakefulness. At least some of the newer AEDs appear to have more favorable sleep-wake profiles than the older agents. In turn, sleep is an important modulator of seizures and epileptic discharges on the electroencephalogram (EEG). Sleep instability can promote seizures and sleep deprivation provokes seizures and EEG abnormalities. Synchronized Non-REM (NREM) sleep facilitates seizures, whereas the clinical and EEG manifestations of epilepsy are suppressed in REM sleep. The sleep EEG is useful in the diagnosis and localization of epilepsy. New epileptic foci can appear in sleep and REM sleep demonstrates the most precise localization of the epileptic discharge. Polysomnography combined with video and EEG (VEEG-PSG) aids in the differentiation of seizures and parasomnias. Daytime sleepiness and sleep disorders such as sleep apnea are common in people with epilepsy. Treating sleep apnea has been shown to reduce EEG abnormalities and seizures in some cases. These observations underscore the importance of a routine sleep assessment in case of all the people with epilepsy.
