An investigator from University of Oxford, UK, reviews the effect of sleep disorders on epilepsy and the effects of epilepsy on sleep. The occurrence of seizures is modified by the circadian sleep-wake cycle, the stage of sleep, sleep deprivation, and obstructive sleep apnea. Certain seizures, such as Rolandic epilepsy, are accentuated during sleep. Nocturnal epilepsy may cause arousals in sleep, and circadian sleep-wake rhythms may be disrupted and cause impaired cognitive function and behavior during the day. Antiepileptic drugs may have indirect effects on sleep. For example, barbiturates cause daytime sleepiness, and phenytoin causes insomnia.
Sleep disorders confused with epilepsy include parasomnias, arousal disorders, sleepwalking, sleep terrors, rhythmic movement disorders (headbanging), nightmares, panic attacks, and REM sleep behavior disorder. Epilepsies confused with sleep disorders include Rolandic epilepsy, Panayiotopoulos syndrome, occipital epilepsy of Gastaut, and nocturnal frontal lobe epilepsy (NFLE) in which seizures occur mainly during sleep. Guidelines are suggested for differentiating non-epileptic parasomnias from nocturnal seizures, and NFLE from arousal disorders. Non-convulsive status is sometimes misinterpreted as a sleep disorder. 
COMMENT. The author concludes that screening for sleep disturbance should be routine in children with epilepsy, and the accurate diagnosis determined, according to the International Classification of Sleep Disorders: Diagnostic and Coding Manual.