Abstracts

Rationale: Extensive compelling evidence has demonstrated the presence of a cortical network for the genesis and propagation of partial seizures. Thus, we evaluated the ictal findings in patients with partial epilepsy (PE) and its correlates with a structurally connected network and possible ipsilateral or contra-lateral propagation using Pairwise Granger Causality (PGC) analysis of raw data EEG recordings in a retrospective case-series study. Methods: First, we studied ictal onset (IO) of fifty-six partial complex seizures (PCS) . Then, we defined seizure directionality using PGC of EEG raw data. Last, we compared the findings against the contra-lateral, non-involved, control, frontal and temporal networks defined by visual analysis of EEG epochs and obtained 113 different PGC data points. Results: PGC was statistically significant, using one way analysis of variance (ANOVA), for intra-hemispheric directionality when the IO was over the right temporal lobe (p=0.0257). PGC showed a trend for a significant intra-hemispheric directionality when the IO was over the left temporal (p=0.0548) and right frontal lobe (p=0.0558). Conclusions: These preliminary findings indicate possible intra-hemispheric ictal propagation for subjects with PE of frontal or temporal ictal onset. It is unclear whether inter-hemispheric ictal propagation is not identifiable with PGC on human scalp EEG recordings. Further studies are indicated to evaluate alternatives methodologies in larger cohorts of individual affected with epilepsy.