Evidence map›Paper›PMID 42378010›Full record

ArticleEpilepsia open2026

Relative entropy as a biomarker for vagus nerve stimulation response in epilepsy: Insights from intracerebral electroencephalography.

Štěpán Erben, Jan Cimbálník, Eva Zatloukalová, Petra Búřilová, Jan Vinklárek, Barbora Sklenárová, Jan Chrastina, Eva Brichtová, Jitka Kočvarová, Ondřej Strýček and 3 more

Abstract read
In one paragraph

Article in Epilepsia open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
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1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

13 authors.

Štěpán ErbenBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0001-9210-6686
Jan CimbálníkInstitute of Scientific Instrument of the Czech Academy of Sciences, Brno, Czech Republic.ORCID https://orcid.org/0000-0001-6670-6717
Eva ZatloukalováBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0003-4364-532X
Petra BúřilováDepartment of Health Science, Faculty of Medicine, Masaryk University, Brno, Czech Republic.ORCID https://orcid.org/0000-0002-8492-8994
Jan VinklárekBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0003-2342-815X
Barbora SklenárováBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0002-7265-9416
Jan ChrastinaDepartment of Neurosurgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.ORCID https://orcid.org/0000-0002-7529-773X
Eva BrichtováDepartment of Neurosurgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic.ORCID https://orcid.org/0000-0003-1348-1758
Jitka KočvarováBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0001-9139-1091
Ondřej StrýčekBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0003-3636-9056
Martin PailBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0003-2059-4822
Milan BrázdilBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0001-7979-2343
Irena DoležalováBrno Epilepsy Center, First Department of Neurology, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Member of ERN-EpiCARE, Brno, Czech Republic.ORCID https://orcid.org/0000-0002-3166-4817

Funding

Czech Science Foundation 22-28594KEuropean Union - Next Generation EU LX22NPO5107MH CZ - DRO 00209805
6 · The paper itself

Abstract

objectiveThis study aims to analyze differences in pre-implantation invasive electroencephalographic (IEEG) data between vagus nerve stimulation (VNS) responders (>50% seizure reduction) and VNS nonresponders (<50% seizure reduction).

methodsWe retrospectively identified 19 patients with drug-resistant focal epilepsy who underwent IEEG followed by VNS implantation instead of resective brain surgery. Resting-state IEEG recordings (30 min) were selected for all patients. Three biomarkers were analyzed in the IEEG data: (1) the number of interictal epileptiform discharges (IEDs), (2) the number of high-frequency oscillations (HFOs; ripples: 80-250 Hz, fast ripples: 250-600 Hz), and (3) relative entropy (all frequency bands, 80-250 Hz, and 250-600 Hz). Analyses were performed in three regions of interest: (1) the all contact zones (ACZ), (2) the seizure-onset zones (SOZ), and (3) the non-seizure onset zones (NON SOZ). Differences between VNS responders and nonresponders were then evaluated. Finally, a statistical classifier was constructed to predict VNS efficacy based on all three biomarkers in the ACZ, SOZ, and non-SOZ.

resultsThe only biomarker that revealed significant differences between VNS responders and nonresponders was Relative Entropy (SOZ: ripples [U = 1, p = 0.18] and fast ripples [U = 8.0, p = 0.009]), but analysis of effect size using Cliff's delta demonstrated large effects across all three zones in the raw signal, ripple, and fast ripple frequency bands. The best accuracy of 0.84 was obtained for the classifier based on the ACZ; the accuracy of the classifier for the SOZ and NON SOZ was 0.72 and 0.79, respectively. SIGNIFICANCE: Invasive electroencephalographic recordings can be used to predict pre-implantation VNS efficacy. In this context, Relative Entropy appears to be a crucial biomarker for distinguishing between VNS responders and nonresponders. PLAIN LANGUAGE SUMMARY: This study shows that brain recordings taken with internal electrodes can help doctors predict whether vagus nerve stimulation will successfully reduce a patient's seizures. We found that a specific measure of brain activity patterns, called Relative Entropy, is a key indicator of whether the treatment will be effective. These findings suggest that analyzing these brain signals can help identify the patients most likely to benefit from vagus nerve stimulation before the device is implanted.

Indexed as

Drug Resistant EpilepsyElectrocorticographyEpilepsies, PartialVagus Nerve StimulationAdolescentAdultBiomarkersElectroencephalographyEntropyFemaleHumansMaleMiddle AgedRetrospective StudiesTreatment OutcomeYoung AdultBiomarkershigh‐frequency oscillationsinterictal epileptiform dischargesintracerebral recordinginvasive EEGpre‐implantation predictionrelative entropy

Identifiers

PMID42378010
PMCPMC13394773

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.