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Clinical impact of a high-frequency seizure onset zone in a case of bitemporal epilepsy Volume 10, issue 3, September 2008

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  • Clinical impact of a high-frequency seizure onset zone in a case of bitemporal epilepsy

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Authors
Department of Neurophysiology, Division of Neuroscience, School of Medicine, The University of Birmingham, Birmingham, United Kingdom, Department of Neurology, 2 nd Faculty of Medicine, Charles University, Motol Hospital, Prague, Czech Republic, Department of Neurosurgery, 1 st Faculty of Medicine, Charles University, Central Military Hospital, Prague, Czech Republic, Department of Developmental Epileptology, Institute of Physiology, Czech Academy of Science, Prague, Czech Republic, Cercia, School of Computer Science, The University of Birmingham, Birmingham, United Kingdom

High-frequency activity has been described as having a role in the initiation of epileptic seizures. The case of a patient with refractory bitemporal epilepsy is presented. Extraoperative monitoring with depth and subdural electrodes revealed an ictal pattern with a build-up of high-frequency (> 80 Hz) activity originating in the cortex, with spread to both hippocampi. This observation was only revealed with the use of high-pass filtering, and represented crucial information that significantly influenced the decision about the side, localization and extent of resection. Removal of the cortex generating high-frequency activity, led to cessation of seizures in this patient. Current knowledge about the role of high-frequency activity and the case presented here support the importance of recording with equipment capable of detecting fast activity during the presurgical invasive monitoring. An active search for a high-frequency seizure onset zone in patients with structurally-unaffected hippocampi may improve the outcome beyond that possible with conventional bandwidth, invasive EEG recordings. [Published with video sequences]