Evidence map›Paper›PMID 40493007›Full record

ArticleEpilepsia2025

Magnetoencephalographic detection of the epileptic activity localized in the hippocampus using stereotactic electroencephalography and magnetoencephalography simultaneously.

Akitake Okamura, Akira Hashizume, Kota Kagawa, Go Seyama, Atsuo Yoshino, Shigeto Yamawaki, Nobutaka Horie, Koji Iida

Abstract read
In one paragraph

Article in Epilepsia, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
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

2 citing papers in PubMed.

  1. Article
  2. Article
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

8 authors.

Akitake OkamuraDepartment of Neurosurgery, Hiroshima University Hospital, Hiroshima, Japan.ORCID https://orcid.org/0000-0002-8534-8801
Akira HashizumeDepartment of Neurosurgery, Hiroshima University Hospital, Hiroshima, Japan.
Kota KagawaDepartment of Neurosurgery, Hiroshima University Hospital, Hiroshima, Japan.
Go SeyamaDepartment of Neurosurgery, Hiroshima University Hospital, Hiroshima, Japan.
Atsuo YoshinoCenter for Brain, Mind and KANSEI Science Research, Hiroshima University, Hiroshima, Japan.
Shigeto YamawakiCenter for Brain, Mind and KANSEI Science Research, Hiroshima University, Hiroshima, Japan.
Nobutaka HorieDepartment of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Koji IidaEpilepsy Center, Hiroshima University Hospital, Hiroshima, Japan.

Funding

Japan Science and Technology Agency (JST) JPMJMS2296Japan Society for the Promotion of Science 23K11919
6 · The paper itself

Abstract

objectiveTo evaluate the ability of magnetoencephalography (MEG) to detect the activity of a deep brain structure, particularly the hippocampus, using simultaneous stereotactic electroencephalography (SEEG) and MEG recordings.

methodsWe included six patients with intractable temporal lobe epilepsy who underwent simultaneous SEEG and MEG. We recorded SEEG spikes and examined the MEG waveforms. We defined S-MEG spikes as MEG spikes synchronized with SEEG spikes in the deep brain structures. We examined the proportion of S-MEG spikes relative to SEEG spikes, the amplitude of S-MEG spikes, and the signal-to-noise ratio (SNR). We also examined the relationship between the spread of epileptic activity and the SNR of S-MEG spikes. We used SEEG spike-indexed averaging to improve the SNR and visualize the source of the S-MEG spikes.

resultsWe recorded 1630 SEEG spikes, of which 575 (35.3%) were identified as S-MEG spikes. The mean amplitude of the S-MEG spikes derived from hippocampal spikes was 163 femtotesla per centimeter (fT/cm), significantly lower than the amplitude from spikes of cortical tissue (p < .001). The mean SNR of S-MEG spikes derived from hippocampal spikes was 0.96, significantly lower than that of cortical tissue spikes (p < .001). The mean SNR of S-MEG spikes derived from hippocampal interelectrode synchronized SEEG spikes was 1.09, significantly greater than the mean SNR of 0.92 without interelectrode synchronization (p = .0035). SEEG spike-indexed averaging could improve the poor SNR and depict dipoles in the hippocampi. SIGNIFICANCE: We detected MEG spikes localized in the hippocampus, the amplitude and SNR of which were significantly lower than those of spikes originating from the cortex. As it spreads, hippocampal epileptic activity becomes easier to detect with MEG, but it remains challenging for MEG to improve the poor SNR to detect the limited hippocampal activity without SEEG.

Indexed as

Drug Resistant EpilepsyElectroencephalographyEpilepsy, Temporal LobeHippocampusMagnetoencephalographyStereotaxic TechniquesAdultFemaleHumansMaleMiddle AgedSignal-To-Noise RatioYoung Adultepilepsyhippocampusmagnetoencephalographysimultaneous recordingstereotactic electroencephalography

Identifiers

PMID40493007
PMCPMC12455452

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC
Read underepoch 390

Registered trials

None linked

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.