Evidence map›Paper›PMID 40152156›Full record

ArticleThe Laryngoscope2025

Functional but Not Structural Brain Changes After Olfactory Training in Women With COVID-19-Associated Olfactory Dysfunction.

Zetian Li, Julia Gebler, Akshita Joshi, Xinni Xu, Divesh Thaploo, Antje Hähner, Vittoria Avaro, Federico Calegari, Thomas Hummel

RetractedAbstract readRetracted Publication
PubMed Full text at PMC Publisher
In one paragraph

Article in The Laryngoscope, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It has been retracted, and should not be counted. Cited by 4 papers.

0numbers the graph read from it
0cells of the map it votes in
4citing 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

4 citing papers in PubMed.

  1. Review
  2. Article
  3. Review
  4. Review
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

9 authors.

Zetian LiSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.ORCID 0000-0003-2170-8916
Julia GeblerSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Akshita JoshiSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Xinni XuSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.ORCID 0000-0002-7534-2545
Divesh ThaplooSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Antje HähnerSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
Vittoria AvaroCRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany.
Federico CalegariCRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany.
Thomas HummelSmell & Taste Clinic, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

Funding

Deutsche Forschungsgemeinschaft DFG CA 893/22-1
6 · The paper itself

Abstract

backgroundOlfactory training (OT) is a recommended treatment for olfactory loss and has proven effective in clinical contexts, yet its effects on the central-nervous system remain unclear. This study aimed to investigate the functional and structural brain changes in patients with post-viral olfactory loss undergoing OT.

methodsTwenty patients with post-viral olfactory loss and 19 healthy controls underwent OT for 3 months. All participants were assessed using the Sniffin' Sticks test and magnetic resonance imaging (MRI). Voxel-based morphometry and olfactory bulb volumetry were performed on structural images. Presenting an unpleasant odor, n-butanol, in a canonical block design, functional MRI was performed using whole-brain and region of interest analyses.

resultsPatients with post-viral olfactory loss showed significant improvement following OT. Enhanced functional activations were observed in the orbitofrontal cortex and parahippocampus, while OT had little or no effects on brain structures.

conclusionThe present findings suggest that OT provides early perceptual and functional benefits, with structural changes potentially emerging later with extended training duration. LEVEL OF EVIDENCE: 2:

Indexed as

BrainCOVID-19Olfaction DisordersAdultCase-Control StudiesFemaleHumansMagnetic Resonance ImagingMiddle AgedOlfactory BulbOlfactory TrainingSARS-CoV-2SmellCOVIDMRIolfactory lossolfactory trainingsmell

Identifiers

PMID40152156
PMCPMC12082003

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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.