Sleep-Related Epilepsy, Dysautonomia, and Sudden Nocturnal Death

Sleep and epilepsy have an intimate relationship. Some epilepsy syndromes are characterized by seizures occurring mostly or exclusively during sleep or on awakening. Many studies have reported autonomic changes in epileptic patients both during seizures and in the interictal state. Sudden unexpected death in epilepsy (SUDEP) is related to the concurrence of a number of predisposing and precipitating factors. Specifically, autonomic dysfunction has been identified as one of the major pathogenetic mechanisms of this fatal event. Moreover, SUDEP is considered primarily a sleep-related phenomenon and evidence suggests that the autonomic changes observed in epileptic patients are mainly evident during nocturnal sleep. In this chapter, we illustrate the clinical aspects of different sleep-related seizures, reporting the available data regarding modification of the cardiac autonomic modulation in each type of these syndromes. Furthermore, we discuss the new findings about SUDEP, focusing on the role of sleep and the autonomic nervous system (ANS) dysfunction in its pathogenesis.