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Reproducibility of interictal spike propagation in children with refractory epilepsy
Author(s) -
Tomlinson Samuel B.,
Wong Jeremy N.,
Conrad Erin C.,
Kennedy Benjamin C.,
Marsh Eric D.
Publication year - 2019
Publication title -
epilepsia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.687
H-Index - 191
eISSN - 1528-1167
pISSN - 0013-9580
DOI - 10.1111/epi.14720
Subject(s) - ictal , electroencephalography , spike (software development) , epilepsy , reproducibility , neuroscience , psychology , audiology , medicine , mathematics , computer science , statistics , software engineering
Summary Objective Interictal spikes are a characteristic feature of invasive electroencephalography (EEG) recordings in children with refractory epilepsy. Spikes frequently co‐occur across multiple brain regions with discernable latencies, suggesting that spikes can propagate through distributed neural networks. The purpose of this study was to examine the long‐term reproducibility of spike propagation patterns over hours to days of interictal recording. Methods Twelve children (mean age 13.1 years) were retrospectively studied. A mean ± standard deviation (SD) of 47.2 ± 40.1 hours of interictal EEG recordings were examined per patient (range 17.5‐166.5 hours). Interictal recordings were divided into 30‐minute segments. Networks were extracted based on the frequency of spike coactivation between pairs of electrodes. For each 30‐minute segment, electrodes were assigned a “Degree Preference (DP)” based on the tendency to appear upstream or downstream within propagation sequences. The consistency of DPs across segments (“DP‐Stability”) was quantified using the Spearman rank correlation. Results Regions exhibited highly stable preferences to appear upstream, intermediate, or downstream in spike propagation sequences. Across networks, the mean ± SD DP‐Stability was 0.88 ± 0.07, indicating that propagation patterns observed in 30‐minute segments were representative of the patterns observed in the full interictal window. At the group level, regions involved in seizure generation appeared more upstream in spike propagation sequences. Significance Interictal spike propagation is a highly reproducible output of epileptic networks. These findings shed new light on the spatiotemporal dynamics that may constrain the network mechanisms of refractory epilepsy.