Invasive Electrophysiological Monitoring

The indications, limitations, technical considerations, and interpretation of invasive electrophysiological monitoring (IEM) in the surgical epilepsy evaluation are discussed in this chapter. Authors identify patient characteristics in which invasive monitoring, via stereo-electroencephalography (SEEG) or placement of depth, grid or strip electrodes, leads to more accurate identification of the epileptogenic region (ER), minimization of cortical resection, and successful removal of seizure foci in close proximity to eloquent cortex. An in-depth discussion of the intricacies of intracranial EEG interpretation is included and will help readers identify patterns of activity that may differentiate the ictal onset zone from an irritative zone or region of static functional abnormality.