Evidence map›Paper›PMID 39487626›Full record

ArticleHuman brain mapping2024

Olfactory Dysfunction and Limbic Hypoactivation in Temporal Lobe Epilepsy.

Markus Schmidt, Tobias Bauer, Marcel Kehl, Anna Minarik, Lennart Walger, Johannes Schultz, Martin S Otte, Peter Trautner, Christian Hoppe, Tobias Baumgartner and 5 more

Abstract read
In one paragraph

Article in Human brain mapping, 2024. 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. Review
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

15 authors.

Markus SchmidtDepartment of Neuroradiology, University Hospital Bonn, Bonn, Germany.
Tobias BauerDepartment of Neuroradiology, University Hospital Bonn, Bonn, Germany.ORCID 0000-0002-0555-6214
Marcel KehlDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Anna MinarikDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Lennart WalgerDepartment of Neuroradiology, University Hospital Bonn, Bonn, Germany.
Johannes SchultzInstitute of Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.ORCID 0000-0003-4117-232X
Martin S OtteDepartment of Otorhinolaryngology, Head and Neck Surgery, Medical Faculty, University of Cologne, Cologne, Germany.
Peter TrautnerInstitute of Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.
Christian HoppeDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Tobias BaumgartnerDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Louisa Specht-RiemenschneiderCenter for Medical Data Usability and Translation, University of Bonn, Bonn, Germany.
Florian MormannDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Alexander RadbruchDepartment of Neuroradiology, University Hospital Bonn, Bonn, Germany.
Rainer SurgesDepartment of Epileptology, University Hospital Bonn, Bonn, Germany.
Theodor RüberDepartment of Neuroradiology, University Hospital Bonn, Bonn, Germany.ORCID 0000-0002-6180-7671

Funding

BONFOR Research Commission of the Medical Faculty of the University of Bonn 2022-1A-21BONFOR Research Commission of the Medical Faculty of the University of Bonn 2022-4-31
6 · The paper itself

Abstract

The epileptogenic network in temporal lobe epilepsy (TLE) contains structures of the primary and secondary olfactory cortex such as the piriform and entorhinal cortex, the amygdala, and the hippocampus. Olfactory auras and olfactory dysfunction are relevant symptoms of TLE. This study aims to characterize olfactory function in TLE using olfactory testing and olfactory functional magnetic resonance imaging (fMRI). We prospectively enrolled 20 individuals with unilateral TLE (age 45 ± 20 years [mean ± SD], 65% female, 90% right-handed) and 20 healthy individuals (age 33 ± 15 years [mean ± SD], 35% female, 90% right-handed). In the TLE group, the presumed seizure onset zone was left-sided in 75%; in 45% of the individuals with TLE limbic encephalitis was the presumed etiology; and 15% of the individuals with TLE reported olfactory auras. Olfactory function was assessed with a Screening Sniffin' Sticks Test (Burkhart, Wedel, Germany) during a pre-assessment. During a pre-testing, all individuals were asked to rate the intensity, valence, familiarity, and associated memory of five different odors (eugenol, vanillin, phenethyl alcohol, decanoic acid, valeric acid) and a control solution. During the fMRI experiment, all individuals repeatedly smelled eugenol (positively valenced odor), valeric acid (negatively valenced odor), and the control solution and were asked to rate odor intensity on a five-point Likert scale. We acquired functional EPI sequences and structural images (T1, T2, FLAIR). Compared to healthy individuals, individuals with TLE rated the presented odors as more neutral (two-sided Mann-Whitney U tests, FDR-p < 0.05) and less familiar (two-sided Mann-Whitney U tests, FDR-p < 0.05). fMRI data analysis revealed a reduced response contrast in secondary olfactory areas (e.g., hippocampus) connected to the limbic system when comparing eugenol and valeric acid in individuals with TLE when compared with healthy individuals. However, no lateralization effect was obtained when calculating a lateralization index by the number of activated voxels in the olfactory system (two-sided Mann-Whitney U test; U = 176.0; p = 0.525). TLE is characterized by olfactory dysfunction and associated with hypoactivation of secondary olfactory structures connected to the limbic system. These findings contribute to our understanding of the pathophysiology of TLE. This study was preregistered on OSF Registries (www.osf.io).

Indexed as

Epilepsy, Temporal LobeMagnetic Resonance ImagingOlfaction DisordersAdultFemaleHumansLimbic SystemMaleMiddle AgedYoung Adultfunctional MRIneurological disorderolfactometrysense of smell

Identifiers

PMID39487626
PMCPMC11530705

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.