Evidence map›Paper›PMID 41281896›Full record

ArticleBrain, behavior, & immunity - health2025

Functional olfactory impairment and fatigue in post-COVID-19 syndrome including ME/CFS - a longitudinal prospective observational study.

Lil Meyer-Arndt, Greta Pierchalla, Lukas Mödl, Felix Wohlrab, Franziska Legler, Uta Hoppmann, Claudia Kedor, Kirsten Wittke, Helma Freitag, Frank Konietschke and 5 more

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Article in Brain, behavior, & immunity - health, 2025. 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
–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

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

15 authors.

Lil Meyer-ArndtExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Greta PierchallaCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Otorhinolaryngology, CCM and CVK, 10117, Berlin, Germany.
Lukas MödlCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, 10117, Berlin, Germany.
Felix WohlrabExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Franziska LeglerExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Uta HoppmannExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Claudia KedorCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt Universität zu Berlin and Berlin Institute of Health, Institute of Medical Immunology, 13353, Berlin, Germany.
Kirsten WittkeCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt Universität zu Berlin and Berlin Institute of Health, Institute of Medical Immunology, 13353, Berlin, Germany.
Helma FreitagCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt Universität zu Berlin and Berlin Institute of Health, Institute of Medical Immunology, 13353, Berlin, Germany.
Frank KonietschkeCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Biometry and Clinical Epidemiology, 10117, Berlin, Germany.
Heidi OlzeCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Otorhinolaryngology, CCM and CVK, 10117, Berlin, Germany.
Friedemann PaulExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Carmen ScheibenbogenCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt Universität zu Berlin and Berlin Institute of Health, Institute of Medical Immunology, 13353, Berlin, Germany.
Judith Bellmann-StroblExperimental and Clinical Research Center, A Cooperation between the Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
Ulrike Förster-RuhrmannCharité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Department of Otorhinolaryngology, CCM and CVK, 10117, Berlin, Germany.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Post-COVID-19 syndrome (PCS) affects a significant proportion of individuals, with olfactory impairment and fatigue as prominent long-term symptoms. A subset of PCS patients with pronounced fatigue meets the diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), here referred to as PCS-ME/CFS. This study explores the relationship between PCS, fatigue, and olfactory function, and investigates the potential of olfactory impairment as a diagnostic and prognostic marker. We assessed olfactory function up to 28 months post-COVID-19 in 45 PCS patients (22 PCS, 23 PCS-ME/CFS) using the extended Sniffin' Sticks test, which evaluates odor threshold, discrimination, and identification, providing a composite score. Fatigue severity and health-related quality of life were assessed using validated questionnaires, a standardized test measured cognitive function, and handgrip strength indicated physical fatiguability. Both PCS and PCS-ME/CFS patients showed significant improvement in olfactory function, with all patients returning to normosmia after 20 months, regardless of diagnosis. While odor threshold was the most affected olfactory measure in Sniffin' Sticks testing, odor identification was the only measure that remained impaired over time. Olfactory impairment correlated with cognitive, physical, and mental performance, with stronger correlations in the PCS group, particularly linking better odor discrimination at baseline to improved daily functioning and health-related quality of life after 20 months. Our findings suggest that odor identification assessed in standardized testing may remain impaired the longest in patients with persisting symptoms after COVID-19, reflecting persisting central processing difficulties. Correlations between olfactory performance, cognitive function, and physical ability point to shared underlying mechanisms. Early olfactory improvements may be linked to better long-term cognitive outcomes, highlighting a possible prognostic role of olfactory function in these patients.

Indexed as

Cognitive deficitsFatigueME/CFSOlfactory dysfunctionPost-COVID-19 syndrome

Identifiers

PMID41281896
PMCPMC12634829

What OpenQuestion holds

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LicenceCC BY-NC-ND
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Registered trials

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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.