Accurate and complete seizure descriptions will allow the reader to elicit maximum benefit from the information contained in the chapters of this section. Ictal semiology remains the most reliable guide to the classification of the seizure disorder, localization of onset of focal seizures, and pathways of propagation.

Such meticulous descriptions will either identify these aspects with certainty or suggest the most likely possibilities, so that cogent questions can be applied to further stages of enquiry such as the neurological examination, electroencephalogram (EEG), and other tests. Attack descriptions may even identify some or all events as nonepileptic.

Aura and epilepsy, the two most common terms applied to seizure disorders, are good examples of the importance of accurate seizure description. The term aura, meaning “breeze” in the Greek language, was apparently first applied to initial manifestations of focal seizures by Pelops, Master of Galen (AD130–210), who described a seizure onset as a “cold breeze.”¹⁶ Patients often describe the succeeding ictal phase as “going into it.” This sensation possibly resembles the meaning of epilepsia, also a Greek term, as “a taking hold of, something seizing the subject as though that ‘something’ were outside himself.”¹⁸

The value of ictal features in localizing involved areas of the brain was first indicated by John Hughlings Jackson, who correlated semiology with sites of lesions disclosed at postmortem pathological examination.¹² Such associations were supplemented by those disclosed by electrical stimulation of the cortex by Fritsch and Hitzig in 1870.¹³ A most comprehensive description of ictal semiology and its seizure-localizing value was achieved by Penfield and Jasper in authoring Epilepsy and the Functional Anatomy of the Human Brain in 1954 (see further).²¹

The physician should obtain as much of the seizure description from the child or adult patient as possible, because only he may possess a detailed description of the most localizing features early in the attack. Patients who initially deny having auras may change their response if asked “Do you ever think you are going to have a seizure, and you don’t have it?” If affirmed, the physician then can ask, “Do some of your seizures begin like that?” Because symptoms such as an epigastric or cephalic sensation may reflect seizure origin from one of several regions, inquiring about symptoms or signs relative to neighboring regions may refine localization possibilities. Seizures involving primary motor or sensory regions may be easier for the patient to describe and localize than those from association areas such as the limbic system. Thus, vaguely described symptoms more likely reflect involvement of such regions, rather than simply a “poor historian.” Observations by family or associates, although of considerable value, may pertain to phenomena occurring later in the ictal sequence and therefore may represent ictal spread rather than origin. Observers may mislateralize ictal phenomena, such as automatisms or dystonia. Once they are made more aware of its clinical value, observers’ scrutiny of such subsequent seizures or in-hospital video monitoring may improve the lateralizing value of such data.

Ajmone Marsan and Ralston provided further data concerning the localizing value of ictal signs and symptoms through study of EEG- and video-recorded pentylenetetrazol (Metrazol)-induced seizures in patients with focal epilepsy. They cautioned that a given semiology may represent (a) various foci among patients and (b) ictal propagation as well as origin.¹