Anatomic consistencies across epilepsies: A stereotactic-EEG informed high-resolution structural connectivity study

Pierre Besson*, S. Kathleen Bandt, Timothcrée Proix, Stanislas Lagarde, Viktor K. Jirsa, Jean Philippe Ranjeva, Fabrice Bartolomei, Maxime Guye

*Corresponding author for this work

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Drug-resistant localization-related epilepsies are now recognized as network diseases. However, the exact relationship between the organization of the epileptogenic network and brain anatomy overall remains incompletely understood. To better understand this relationship, we studied structural connectivity obtained from diffusion weighted imaging in patients with epilepsy using both stereoelectroencephalography (SEEG)-determined epileptic brain regions and whole-brain analysis. High resolution structural connectivity analysis was applied in 15 patients with drug-resistant localization-related epilepsies and 36 healthy control subjects to study structural connectivity changes in epilepsy. Two different methods of structural connectivity analysis were carried out using diffusion weighted imaging, one focusing on the relationship between epileptic regions determined by SEEG investigations and one blinded to epileptic regions looking at whole-brain connectivity. First, we performed zone-based analysis comparing structural connectivity findings in patients and controls within and between SEEG-defined zones of interest. Next, we performed whole-brain structural connectivity analysis in all subjects and compared findings to the same SEEG-defined zones of interest. Finally, structural connectivity findings were correlated against clinical features. Zone-based analysis revealed no significant decreased structural connectivity within nodes of the epilepsy network at the group level, but did demonstrate significant structural connectivity differences between nodes of the epileptogenic network (regions involved in seizures generation and propagation) and the remaining of the brain in patients compared to controls. Whole-brain analyses showed a total of 133 clusters of significantly decreased structural connectivity across all patients. One cluster of significantly increased structural connectivity was identified in a single patient. Clusters of decreased structural connectivity showed topographical preference for both the salience and default mode networks despite clinical heterogeneity within our patient sample. Correlation analysis did not reveal any significant findings regarding either the effect of age at disease onset, disease duration or post-surgical outcome on structural connectivity. Taken together, this work demonstrates that structural connectivity disintegration targets distributed functional networks while sparing the epilepsy network.

Original languageEnglish (US)
Pages (from-to)2639-2652
Number of pages14
JournalBrain
Volume140
Issue number10
DOIs
StatePublished - Jan 1 2017

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Keywords

  • SEEG
  • brain networks
  • diffusion weighted imaging
  • epilepsy
  • structural connectivity

ASJC Scopus subject areas

  • Clinical Neurology

Cite this

Besson, P., Bandt, S. K., Proix, T., Lagarde, S., Jirsa, V. K., Ranjeva, J. P., Bartolomei, F., & Guye, M. (2017). Anatomic consistencies across epilepsies: A stereotactic-EEG informed high-resolution structural connectivity study. Brain, 140(10), 2639-2652. https://doi.org/10.1093/brain/awx181