When is temporal lobe epilepsy not temporal lobe epilepsy?

Abstract

This scientific commentary refers to ‘Temporal plus epilepsy is a major determinant of temporal lobe surgery failures’, by Barba et al. . (doi:10.1093/brain/awv372). Stereotactic electroencephalography (SEEG) originated in France in the 1950s. Bancaud and Talairach, at St. Anne’s Hospital in Paris, introduced this approach to define the 3D extent of dysfunctional brain tissue surrounding intraparenchymal brain tumours, and more specifically, to define epileptogenic brain tissue in patients with pharmacoresistant epileptic seizures (Bancaud et al. , 1975). The approach required a hypothesis that would enable the placement of multiple, mostly unilateral, depth electrodes to sample a reasonably limited number of regions of interest. The results then guided a tailored surgical resection. This technique was adapted by Crandall et al. (1963) at UCLA for patients with suspected mesial temporal lobe epilepsy. Crandall, however, used a standardized, bilaterally symmetrical, depth electrode approach, designed to sample those structures known to be primarily involved in generating limbic seizures. Because French law did not allow Bancaud and Talairach to leave their electrodes in place for more than a few hours, their analyses were based on interictal activity, as well as electrically and chemically induced seizures. Crandall, therefore, was the first to perform chronic depth electrode recording, over days and weeks, in order to capture spontaneous ictal events. Because investigators at UCLA had recently developed an EEG telemetry device for NASA to record from chimpanzees orbiting in space, Crandall was also able to use this new technology to establish EEG telemetry for long-term monitoring of epileptic seizures. Data were used to determine that the epileptogenic region was contained within the area of a standardized anterior temporal resection (Falconer, 1953), which was then performed routinely. Two schools of invasive presurgical evaluation for epilepsy surgery then evolved: the French school, which performed classical SEEG, using multiple electrodes …