How important is the seizure onset zone for seizure dynamics?

Seizure. 2015 Feb;25:160-6. doi: 10.1016/j.seizure.2014.10.013. Epub 2014 Oct 31.

Abstract

Purpose: Research into epileptic networks has recently allowed deeper insights into the epileptic process. Here we investigated the importance of individual network nodes for seizure dynamics.

Methods: We analysed intracranial electroencephalographic recordings of 86 focal seizures with different anatomical onset locations. With time-resolved correlation analyses, we derived a sequence of weighted epileptic networks spanning the pre-ictal, ictal, and post-ictal period, and each recording site represents a network node. We assessed node importance with commonly used centrality indices that take into account different network properties.

Results: A high variability of temporal evolution of node importance was observed, both intra- and interindividually. Nevertheless, nodes near and far off the seizure onset zone (SOZ) were rated as most important for seizure dynamics more often (65% of cases) than nodes from within the SOZ (35% of cases).

Conclusion: Our findings underline the high relevance of brain outside of the SOZ but within the large-scale epileptic network for seizure dynamics. Knowledge about these network constituents may elucidate targets for individualised therapeutic interventions that aim at preventing seizure generation and spread.

Keywords: Centrality; Epileptic networks; Graph analysis; Node importance; Seizure onset zone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Brain / physiopathology*
  • Child
  • Electrodes, Implanted
  • Electroencephalography
  • Epilepsy / physiopathology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neural Pathways / physiopathology
  • Retrospective Studies
  • Seizures / physiopathology*
  • Signal Processing, Computer-Assisted
  • Young Adult