title: Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography.
abstract: Cortico-cortical evoked potentials offer the possibility of understanding connectivity within seizure networks to improve diagnosis and more accurately identify candidates for seizure surgery. We sought to determine if cortico-cortical evoked potentials and post-stimulation oscillatory changes differ for sites of EARLY versus LATE ictal spread. 37 patients undergoing stereoelectroencephalography were tested using a cortico-cortical evoked potential paradigm. All electrodes were classified according to the speed of ictal spread. EARLY spread sites were matched to a LATE spread site equidistant from the onset zone. Root-mean-square was used to quantify evoked responses and post-stimulation gamma band power and coherence were extracted and compared. Sites of EARLY spread exhibited significantly greater evoked responses after stimulation across all patients (t(36)=2.973, p=0.004). Stimulation elicited enhanced gamma band activity at EARLY spread sites (t(36)=2.61, p=0.03, FDR corrected); this gamma band oscillation was highly coherent with the onset zone. Cortico-cortical evoked potentials and post-stimulation changes in gamma band activity differ between sites of EARLY versus LATE ictal spread. The oscillatory changes can help visualize connectivity within the seizure network.
authors.affiliation: Neurological Surgery, The University of Texas-Southwestern, Dallas, TX 75253, USA. Electronic address: bradley.lega@utsouthwestern.edu.
authors.forename: Bradley
authors.initials: B
authors.lastname: Lega
authors.affiliation: Epileptology, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA.
authors.forename: Sasha
authors.initials: S
authors.lastname: Dionisio
authors.affiliation: Epileptology, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Flanigan
authors.affiliation: Epilepsy Surgery, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA.
authors.forename: William
authors.initials: W
authors.lastname: Bingaman
authors.affiliation: Epileptology, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA.
authors.forename: Imad
authors.initials: I
authors.lastname: Najm
authors.affiliation: Epileptology, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA.
authors.forename: Dileep
authors.initials: D
authors.lastname: Nair
authors.affiliation: Epilepsy Surgery, The Cleveland Clinic Epilepsy Institute, Cleveland, OH 44195, USA. Electronic address: GONZALJ1@ccf.org.
authors.forename: Jorge
authors.initials: J
authors.lastname: Gonzalez-Martinez
mesh_terms: D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D004558:Electric Stimulation / Q000379:methods; D000069280:Electrocorticography / Q000379:methods; D004567:Electrodes, Implanted; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012640:Seizures / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Cortical stimulation; Evoked potentials; Seizure networks; Stereoelectroencephalography