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

Peking University Third Hospital150 enrolled

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?

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Interventions

Conventional olfactory training deviceDEVICE

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.

Modified olfactory training deviceDEVICE

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.

Conventional olfactory training device with placeboDEVICE

Based on the traditional olfactory training device, four olfactory odors are replaced by placebo。

Eligibility

Sex: ALLMin age: 18 YearsMax age: 80 Years

Medical Language ↔ Plain English

Inclusion Criteria: 1. Age 18-80 years old, gender not limited. 2. Patients diagnosed with olfactory dysfunction following infections of the upper respiratory tract, as determined by Sniffin' Sticks test (including TDI value test). 3. Voluntarily signs the informed consent form. Exclusion Criteria: 1. Patients with post-traumatic olfactory dysfunction, rhinosinusitis-related dysfunction and olfactory dysfunction caused by other reasons. 2. Patients with concomitant sinonasal disease. 3. Patients with chronic diseases, such as hypertension, diabetes, bronchopneumonia, chronic obstructive pulmonary disease, etc. 4. Patients with serious coexisting diseases: such as malignant tumors, etc., with a life expectancy of less than 2 years. 5. Patients who cannot tolerate olfactory function testing and treatment. 6. Patients who have taken oral glucocorticoids, antibacterial drugs, anti-leukotrienes, antihistamines, or received olfactory training within four weeks will be excluded. 7. Patients who are receiving treatment that affects olfactory recovery. 8. Patients with smoking habits. 9. Patients who are already or plan to be pregnant. 10. 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). 11. Patients who did not consent for participating in the study.

Outcomes

Primary Outcomes

The total scores in the "Sniffin 'Sticks" test

This olfactory test consists of three subtests that respectively measure odor threshold (T), odor discrimination (D), and odor identification (I). Each subtest has a maximum score of 16, and the sum of the scores from the three subtests provides the global olfactory score (TDI score; Threshold, Discrimination, Identification) with a maximum of 48 points. Patients with a TDI composite score≥30.5 are defined as normosmic. In contrast, those with a TDI composite score between 16.5 and 30.5 are defined as hyposmic, and patients with a TDI composite score\<16.5 are defined as functionally anosmic. Based on previous literature, we have established a 5.5 points improvement in the TDI composite score as a significant change.