Cortico-cortical evoked potentials for sites of early versus late seizure spread in stereoelectroencephalography

Bradley Lega, Sasha Dionisio, Patrick Flanigan, William Bingaman, Imad Najm, Dileep Nair, Jorge Gonzalez-Martinez

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)17-29
Number of pages13
JournalEpilepsy Research
StatePublished - Sep 1 2015


  • Cortical stimulation
  • Evoked potentials
  • Seizure networks
  • Stereoelectroencephalography

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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