Intracranial electrodes in the presurgical evaluation of epilepsy

Abstract

The resection of the epileptogenic area of brain is very important and useful for the treatment of uncontrolled epilepsy, especially for the patients with stereotyped partial seizures. The critical point for successful epilepsy surgery is the precise identification of epileptogenic zone. Actually, we cannot precisely localize the epileptogenic zone in about 25 % of patient with refractory seizures based on the noninvasive examination; thus for these patients, we mainly use the intracranial EEG to localize the epileptogenic zone which could be useful in 10-15 % of surgical candidates. The intracranial electrodes which are most used currently are depth electrodes, subdural strip electrodes, and subdural grid electrodes. The subject of this paper is to discuss and compare the indications, construction, insertion, interpretation, limitations, risks and accuracy of each of these methods.

Yield of MRI, high-density electric source imaging (HD-ESI), SPECT and PET in epilepsy surgery candidates

“…: video-electroencephalogram [EEG], magnetic resonance imaging [MRI], positron emission tomography [PET] and single-photon emission computed tomography [SPECT]) (Knowlton et al, 2008;Schramm and Clusmann, 2008). In some patients, intracranial EEG monitoring is necessary (Rosenow and Luders, 2001;Knowlton et al, 2008;Schramm and Clusmann, 2008;Yuan et al, 2012).…”

Focal Seizures Induced by Intracranial Electroencephalogram Grids

“…Medically refractory epilepsy occurs in 33% of epilepsy patients, and surgical treatment results in seizure freedom for greater than 50% of these patients, improving quality of life and reducing mortality [2-3]. Intracranial electroencephalograms are indicated when the seizure localization on scalp electroencephalograms (EEGs) is indeterminate or when the clinical, electrographic, and radiographic data are incongruent [4-5]. The spatial resolution and direct cortical contact afforded by iEEG refine seizure location.…”

Multi-trajectories automatic planner for StereoElectroEncephaloGraphy (SEEG)

“…Nonetheless, 5-50 % of the subjects undergo intracranial electroencephalography to record both interictal and ictal brain activity [17,31,35,36]. Intracerebral electrodes allow the accurate sampling of lateral, mesial and inferior aspects of the cortical surface, of the white matter and of the subcortical gray matter structures, with a low complication rate [6].…”