intercalated seizure intercalated seizure an intercalated seizure is an epileptic seizure that occurs during the aura stage of a migraine. it has been found, in some cases, that this type of seizure is instigated by the migraine preceding it, coining the term "migraine-triggered seizure". in order to be considered such, the victim must have already had certified migraines with aura and a seizure must occur within one hour after the beginning of the aura. the neurological condition that combines migraines with epileptic seizures is known as migralepsy.