Evidence map›Paper›PMID 40916858›Full record

ArticleMovement disorders clinical practice2026

Prodromal Lewy Body Symptoms and α-Synuclein Seeding in Idiopathic Olfactory Dysfunction.

Oskar Hoffmann McWilliam, Remarh Bsoul, Gunhild Waldemar, Steen Gregers Hasselbalch, Anja Hvid Simonsen, Marie Bruun, Laura Storm Næsborg Andersen, Christian von Buchwald, Kasper Aanæs, Christian K Pedersen and 6 more

Abstract read
In one paragraph

Article in Movement disorders clinical practice, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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

1 citing paper in PubMed.

  1. 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

16 authors.

Oskar Hoffmann McWilliamDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.ORCID https://orcid.org/0000-0001-9728-8773
Remarh BsoulDepartment of Pathology, Danish Reference Center for Prion Disease, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Gunhild WaldemarDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Steen Gregers HasselbalchDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Anja Hvid SimonsenDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Marie BruunDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Laura Storm Næsborg AndersenDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Christian von BuchwaldDepartment of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Kasper AanæsDepartment of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Christian K PedersenDepartment of Otolaryngology, Head and Neck Surgery and Audiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Ida S B AndersenDepartment of Otolaryngology, Head and Neck Surgery and Audiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Magne BechDepartment of Otolaryngology, Head and Neck Surgery and Audiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Clara Hageman PinborgDepartment of Otolaryngology, Head and Neck Surgery and Audiology, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Aušrinė AreškevičiūtėDepartment of Pathology, Danish Reference Center for Prion Disease, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Eva Løbner LundDepartment of Pathology, Danish Reference Center for Prion Disease, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.
Kristian Steen FrederiksenDepartment of Neurology, Danish Dementia Research Centre, Copenhagen University Hospital-Rigshospitalet, Copenhagen, Denmark.

Funding

Aase og Ejnar Danielsens FondAlzheimer-ForskningsfondenEllen Mørchs FondGrosserer L. F. Foghts FondHarboefondenJascha FondenKong Christian den Tiendes FondOverretssagfører L. Zeuthens MindelegatRigshospitalet's Research Council
6 · The paper itself

Abstract

backgroundEarly identification of pathological α-synuclein deposition (αSynD) may improve understanding of Lewy body disorder (LBD) progression and enable timely disease-modifying treatments.

objectivesWe investigated αSynD using a seed amplification assay and assessed prodromal LBD symptoms in individuals with idiopathic olfactory dysfunction (iOD).

methodsIn this cross-sectional, case-control study, we included iOD participants and normosmic healthy controls (HC) aged 55 to 75 years without diagnoses of dementia with Lewy bodies, Parkinson's disease (PD), or other major neurological disorders. iOD was defined as hyposmia without any known causes. The primary outcome was αSynD detection in skin and olfactory mucosa. Secondary outcomes included prodromal LBD symptoms: cognitive dysfunction, rapid eye movement sleep behavior disorder (RBD), motor and nonmotor symptoms (Movement Disorders Society-Unified Parkinson's Disease Rating Scale [MDS-UPDRS] Parts I-III), and prodromal PD risk.

resultsWe recruited 44 iOD participants (mean age 65) and 50 HCs (mean age 67). Eighteen iOD participants (41%) were αSynD positive in skin and/or olfactory mucosa compared to 1 HC (2%, P < 0.0001). iOD participants had higher rates of cognitive dysfunction (48% vs. 24%, P = 0.02), possible RBD (41% vs. 16%, P = 0.01), and elevated MDS-UPDRS I-III (median [interquartile range]: 15 [7-22] vs. 5.5 [3-11], P < 0.0001). Dysautonomia symptoms did not differ significantly. In the iOD group, 45% met probable/possible prodromal PD criteria versus 1 control (P < 0.0001). However, αSynD-αSynD-negative iOD participants had a nonsignificantly higher prodromal PD risk compared to αSynD-positive individuals.

conclusionsiOD exhibits high αSynD prevalence and prodromal LBD symptoms, supporting its role as an early LBD marker and potential model for early intervention and mechanistic studies.

Indexed as

alpha-SynucleinLewy Body DiseaseOlfaction DisordersProdromal SymptomsAgedCase-Control StudiesCognitive DysfunctionCross-Sectional StudiesFemaleHumansMaleMiddle AgedOlfactory MucosaParkinson DiseaseREM Sleep Behavior Disorderalpha-Synucleindementia with Lewy bodieshyposmiaolfactory dysfunctionParkinson's diseaseprodromal α‐synucleinopathyseed amplification assay

Identifiers

PMID40916858
PMCPMC12911455

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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.