Interactions between sleep and epilepsy

Sleep is one of the best-documented factors influencing the expression of s eizures and interictal discharges. Janz studied the relation between seizur es and the sleep/wake cycle and divided the epilepsies into three categorie s: nocturnal, awakening, and diffuse. Since then, the effect of sleep on th e ictal and interictal manifestations of epilepsy has been studied extensiv ely. Many seizures are activated by sleep or arousal from sleep. Interictal discharges are also seen more commonly during sleep, with the greatest act ivation seen during nonrapid eye movement sleep. Sleep not only increases t he frequency of epileptiform abnormalities, but also may alter their morpho logy and distribution. Sleep deprivation also facilitates both epileptiform abnormalities and seizures. Seizures. on the other hand. also impact sleep . Epileptic patients demonstrate multiple sleep abnormalities, including an increased sleep latency, fragmented sleep, increased awakenings and stage shifts, and an increase in stages 1 and 2 of nonrapid eye movement sleep. T hese disturbances may in turn be modulated by antiepileptic treatment. This review summarizes the interactions between sleep and epilepsy, including t he timing of seizures during the sleep/wake cycle, the influence of sleep o n various seizure disorders, the effects of sleep deprivation, and the chan ges in sleep patterns caused by seizures and their treatment.