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Recruiting NCT06829706

The Efficacy of Modified Olfactory Training Method for Patients With Post-viral Olfactory Dysfunction

No phase Interventional Olfactory Dysfunction Post Viral Olfactory Dysfunction (PVOD)

For patients and families

In plain language

An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.

What is being studied
The protocol lists: Conventional olfactory training device, Modified olfactory training device, Conventional olfactory training device with placebo.
Who it may be relevant to
Registry conditions: Olfactory Dysfunction, Post Viral Olfactory Dysfunction (PVOD). Basic parameters: 18 years — 80 years · All.
What needs checking
Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
Where it takes place
China
Next step
Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →

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Official title

A Randomized Trail Protocol to Access Efficacy of Modified Olfactory Training Method for Patients With Post-viral Olfactory Dysfunction

Overview

The goal of this clinical trial is to validate the effectiveness of the modified olfactory training device, the main questions it aims to answer are: Is the modified olfactory training device effective in treating patients with post-viral olfactory dysfunction? Compared to the conventional device, how efficient is the modified olfactory training device for improving olfactory function?

Detailed description

Background The aim of this article is to present the research protocol for a randomized, controlled, multi-center, placebo study that will assess the olfactory function and the effect of an intervention based on olfactory training in patients with post-viral olfactory dysfunction, and compare it with traditional olfactory training. The sample selection will follow the multi-center principle. The olfactory training (OT) intervention will last for 12 weeks.

Evaluation The primary endpoint will be the change in olfactory ability from baseline to the 12-week intervention or control period. The intervention effect will be evaluated by the total score of the Sniffer Stick Test (SST)-Threshold, Discrimination and Identification (TDI)-Extended Version. Secondary endpoints will be changes in olfactory bulb volume and shape, olfactory-related brain area volume, olfactory and trigeminal nerve-related potentials, and cognitive questionnaires.

Conclusion（objective） The present study aimed to explore the efficacy of the modified olfactory training device (MOT), and compare COT and MOT with respect to the resultant improvement in olfactory function.

At the same time, our study will use a variety of outcome indicators to evaluate the changes in patients before and after treatment, which will lay the foundation for exploring the mechanism of olfactory training in treating patients with post-viral olfactory disorders.

Interventions

  • Device Conventional olfactory training device
    Conventional olfactory training was designed by Hummel et al. They performed OT using four odors (phenyl ethyl alcohol, rose; eucalyptol, eucalyptus; citronella, lemon; and eugenol, cloves), which are representative of four odor categories on the odor prism proposed by Henning.
  • Device Modified olfactory training device
    Participants will use a modified olfactory training device based on expiratory pressure. Its bidirectional airflow and unidirectional pressure characteristics significantly increased the deposition rate of olfactory odors in the olfactory cleft area, making the patient feel stronger in the nasal cavity during olfactory training.
  • Device Conventional olfactory training device with placebo
    Based on the traditional olfactory training device, four olfactory odors are replaced by placebo。

Primary outcome measures

  • The total scores in the "Sniffin 'Sticks" test [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
Secondary outcome measures (7)
  • OB volume and shape measurement [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • MRI volumetric evaluation related to GM [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • MRI volumetric evaluation related to WM [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • MRI volumetric evaluation related to CSF [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • Event-related potentials (ERPs) [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • Questionnaire of Olfactory Disorders [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]
  • Visual analogue scale for olfactory training [Time frame: Baseline,Month 3,Month 6,Month 12,Month 24]

Eligibility criteria

Inclusion criteria

  • Age 18-80 years old, gender not limited.
  • Patients diagnosed with olfactory dysfunction following infections of the upper respiratory tract, as determined by Sniffin' Sticks test (including TDI value test).
  • Voluntarily signs the informed consent form.

Exclusion criteria

  • Patients with post-traumatic olfactory dysfunction, rhinosinusitis-related dysfunction and olfactory dysfunction caused by other reasons.
  • Patients with concomitant sinonasal disease.
  • Patients with chronic diseases, such as hypertension, diabetes, bronchopneumonia, chronic obstructive pulmonary disease, etc.
  • Patients with serious coexisting diseases: such as malignant tumors, etc., with a life expectancy of less than 2 years.
  • Patients who cannot tolerate olfactory function testing and treatment.
  • Patients who have taken oral glucocorticoids, antibacterial drugs, anti-leukotrienes, antihistamines, or received olfactory training within four weeks will be excluded.
  • Patients who are receiving treatment that affects olfactory recovery.
  • Patients with smoking habits.
  • Patients who are already or plan to be pregnant.
  • According to the judgment of the researchers, the patient cannot complete this study or cannot comply with the requirements of this study (such as memory or behavior abnormalities, depression, heavy drinking, previous breach of contract).
  • Patients who did not consent for participating in the study.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation
Randomized
Model
Parallel assignment
Masking
Double blind
Primary purpose
Treatment

Study locations

China · 1 center
  • Bejing — Beijing

Publications

  • Xie J, Li Y, He H, Liu Y, Chen L, Liu X, Zhao D, Wu D. Randomised trial protocol to assess efficacy of modified olfactory training method for patients with postinfectious olfactory dysfunction. BMJ Open. 2025 Dec 23;15(12):e101183. doi: 10.1136/bmjopen-2025-101183. PMID 41436263

Identifiers

NCT: NCT06829706 · 9059103

Primary sources (government registries)

View this study on ClinicalTrials.gov ↗