Open AccessAutomated long‐term EEG analysis to localize the epileptogenic zone
Author(s) -
Mierlo Pieter,
Strobbe Gregor,
Keereman Vincent,
Birot Gwénael,
Gadeyne Stefanie,
Gschwind Markus,
Carrette Evelien,
Meurs Alfred,
Van Roost Dirk,
Vonck Kristl,
Seeck Margitta,
Vulliémoz Serge,
Boon Paul
Publication year - 2017
Publication title -
epilepsia open
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.247
H-Index - 16
ISSN - 2470-9239
DOI - 10.1002/epi4.12066
Subject(s) - spike (software development) , ictal , electroencephalography , cluster (spacecraft) , resection , nuclear medicine , medicine , neuroscience , psychology , computer science , surgery , software engineering , programming language
Summary Objective We investigated the performance of automatic spike detection and subsequent electroencephalogram ( EEG) source imaging to localize the epileptogenic zone ( EZ ) from long‐term EEG recorded during video‐ EEG monitoring. Methods In 32 patients, spikes were automatically detected in the EEG and clustered according to their morphology. The two spike clusters with most single events in each patient were averaged and localized in the brain at the half‐rising time and peak of the spike using EEG source imaging. On the basis of the distance from the sources to the resection and the known patient outcome after surgery, the performance of the automated EEG analysis to localize the EZ was quantified. Results In 28 out of the 32 patients, the automatically detected spike clusters corresponded with the reported interictal findings. The median distance to the resection in patients with Engel class I outcome was 6.5 and 15 mm for spike cluster 1 and 27 and 26 mm for cluster 2, at the peak and the half‐rising time of the spike, respectively. Spike occurrence (cluster 1 vs. cluster 2) and spike timing (peak vs. half‐rising) significantly influenced the distance to the resection (p < 0.05). For patients with Engel class II , III , and IV outcomes, the median distance increased to 36 and 36 mm for cluster 1. Localizing spike cluster 1 at the peak resulted in a sensitivity of 70% and specificity of 100%, positive prediction value ( PPV ) of 100%, and negative predictive value ( NPV ) of 53%. Including the results of spike cluster 2 led to an increased sensitivity of 79% NPV of 55% and diagnostic OR of 11.4, while the specificity dropped to 75% and the PPV to 90%. Significance We showed that automated analysis of long‐term EEG recordings results in a high sensitivity and specificity to localize the epileptogenic focus.