Autonomic symptoms during epileptic seizures.

Autonomic symptoms frequently occur during epileptic seizures either as an accompaniment to other seizure symptoms or as the predominant seizure manifestation. They do not represent simple reactions to motor manifestations of seizures, but are mediated by an activation of the central autonomic network. Autonomic symptoms can be divided into cardiovascular changes, respiratory manifestations, gastrointestinal symptoms, cutaneous manifestations, pupillary symptoms, genital and sexual manifestations as well as urinary symptoms. Due to a hemispheric-specific representation of the central autonomic network, certain autonomic symptoms may provide lateralizing and sometimes localizing information on the seizure onset zone, although some of these signs may appear as a result of discharge spreading. Autonomic symptoms indicating a seizure onset in the non-dominant hemisphere include ictal vomiting and retching, spitting automatisms and ictal urinary urge. Autonomic symptoms range from subtle seizure manifestations which become apparent only during meticulous seizure analysis, to severe, sometimes life-threatening events. Cardiovascular and respiratory autonomic symptoms are discussed as the mechanisms underlying sudden unexplained death in epilepsy. When autonomic symptoms represent the sole seizure manifestation, they can pose problems for differential diagnosis of various non-epileptic conditions. Finally, autonomic seizure symptoms open a unique window on the functional organization of the central autonomic network and on brain function in general. (Published with videosequences.)