Olfactory Training on Smell Dysfunction Patients in HK

Effect of Olfactory Training on Olfactory Dysfunction Patients in Hong Kong Population

• Causes of olfactory dysfunction can be classified into conductive and sensorineural causes.
• Conductive causes are mainly due to structural nasal problem, which can be treated by nasal surgery
• Sensorineural causes included post-infection, post-head injury, post Head and Neck irradiation and other central nervous system diseases.
• Olfactory Training is well established treatment for sensorineural olfactory dysfunction in foreign countries.
• Olfactory Training by neurological chemosensory stimulation using aromatic substances delivered via electronic portable aromatic rehabilitation (EPAR) diffuser was proved to be effective treatment in COVID-19 related olfactory dysfunction in recent Hong Kong study.
• However, there is a lack of local study on the effect of Olfactory Training in other non-COVID-19 sensorineural causes of olfactory dysfunction in Hong Kong population.

Study Overview

• Status: Recruiting
• Conditions: Anosmia; Olfaction Disorders; Hyposmia; Smell Disorders; Smell Loss; Smell Dysfunction; Olfactory Impairment
• Intervention / Treatment: Other: Olfactory Training; Other: Control

Detailed Description

Design Prospective double-blinded randomized control trial.

Study Period 1/7/2022 - 30/6/2024 for case recruitment.

Suitable patient will be recruited. Informed consent will be signed. Objective smell assessment will be done using the University of Pennsylvania Smell Identification Test (UPSIT) and Butanol Threshold Test (BTT). Subjective quality of life score will be obtained by Sino-Nasal Outcome Test (SNOT-22). Subjective smell and taste assessment will be assessed by Visual Analogue Scale (VAS). Patient will be randomized into treatment group and control group using computer generated list by an independent nursing staff. Doctors and the patients will be blinded during the study.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kai Chuen Fergus Wong, FRCSEd(ORL); Phone Number: 64600771; Email: wkc568@ha.org.hk
• Study Contact Backup: Name: Ka Chung Kwan, FRCSEd(ORL); Phone Number: 64600056

Study Locations

• Hong Kong
  • Hong Kong, Hong Kong
    • Recruiting
    • Pamela Youde Nethersole Eastern Hospital
    • Contact: Kai-Chuen, Fergus Wong

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Olfactory dysfunction > 6 months and < 5 years

Exclusion Criteria:

• History of significant head injury (fracture, ICH)
• History of brain surgery
• History of nasal surgery
• Active nasal disease
• Active neurological disease
• Poor premorbid status/ non-communicable patients
• Mentally incompetent patients
• <18 years' old
• Pregnancy
• Hypersensitivity to the aromatic substance.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Treatment arm; Olfactory training by neurological chemosensory stimulation using aromatic substances delivered via diffusers. Four aromatic substances will be used. Each substance will be given for 20 seconds sequentially, providing a total of 80 seconds of olfactory stimulation three times per day for 3 months.	Other: Olfactory Training; Four aromatic substances will be used (Citrus limon, Eucalyptus radiata, Pelargonium graveolens, Juniperus virginiana)
Placebo Comparator: Control arm; Same diffuser will be given to control group. All of the four essential oils will be replaced by normal saline using the same packing. Same treatment regime of 20 seconds for each diffuser three times per day for 3 months will be instructed to control group patients.	Other: Control; Normal Saline will be used

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Olfactory threshold changes after olfactory training after 3 months	Parameter: Olfactory threshold using Butanol Threshold Test (BTT)	3 months after starting smell training
Olfactory identification score changes after olfactory training after 3 months	Parameter: Olfactory identification using Smell Identification Test (UPSIT)	3 months after starting smell training
Quality of life changes after olfactory training after 3 months	Parameter: Subjective quality of life score using Sino-Nasal Outcome Test (SNOT-22)	3 months after starting smell training
Taste and smell changes after olfactory training after 3 months	Parameter: Subjective smell and taste assessment using Visual Analogue Scale (VAS)	3 months after starting smell training

Collaborators and Investigators

• Sponsor: Pamela Youde Nethersole Eastern Hospital
• Investigators: Principal Investigator: Kai Chuen Fergus Wong, FRCSEd(ORL), Pamela Youde Nethersole Eastern Hospital

Study record dates

Study Major Dates

• Study Start (Actual): July 1, 2022
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: April 14, 2022
• First Submitted That Met QC Criteria: May 3, 2022
• First Posted (Actual): May 6, 2022

Study Record Updates

• Last Update Posted (Actual): June 3, 2025
• Last Update Submitted That Met QC Criteria: May 28, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neurologic Manifestations; Nervous System Diseases; Sensation Disorders; Anosmia; Olfaction Disorders
• Other Study ID Numbers: OlfactoryTrainingHKRCT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No