Primary and secondary bilateral synchrony in epilepsy: differentiation by estimation of interhemispheric small time differences during short spike-wave activity

K. Kobayashi, Y. Ohtsuka, E. Oka, S. Ohtahara

Research output: Contribution to journalArticle

60 Citations (Scopus)

Abstract

Estimation of interhemispheric small time differences (TDs) during spike-wave bursts in the EEG by coherence and phase analysis is useful for differentiation between primary bilateral synchrony (PBS) and secondary bilateral synchrony (SBS) in epilepsy. Because the previous method via Fast Fourier Transform needed long bursts for reliable analysis, a method using a 2-dimensional autoregressive model was newly developed to enable estimation of TDs even in 1.2 sec bursts, and applied to 19 epileptic patients with apparently bilaterally synchronous spike-wave bursts. At the onsets of bursts, estimated maximal TDs were 5.8 msec or less and inconsistent in leading hemispheres in 10 patients with a clinical diagnosis of idiopathic, cryptogenic or symptomatic generalized epilepsy indicating PBS, while the maximal TDs were 9.3-41.5 msec and consistent in leading in 7 patients with clinically symptomatic partial epilepsy and also in two with idiopathic and symptomatic generalized epilepsy suggesting SBS. Among 8 patients with bursts which suggested SBS and long enough for evaluation of intra-burst TD variation, TDs tended to disappear in the middle to end parts of the bursts in 5 cases, but not in the other 3, suggesting 2 different pathophysiological mechanisms in SBS.

Original languageEnglish
Pages (from-to)93-103
Number of pages11
JournalElectroencephalography and Clinical Neurophysiology
Volume83
Issue number2
DOIs
Publication statusPublished - Aug 1992

Keywords

  • Autoregressive model
  • Coherence and phase analysis
  • EEG
  • Epilepsy
  • Secondary bilateral synchrony
  • Spike-waves

ASJC Scopus subject areas

  • Neuroscience(all)
  • Clinical Neurology

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