Olfaction DisordersNCT05364125
Olfactory Training on Smell Dysfunction Patients in HK
A study testing Olfactory Training in people with Olfaction Disorders and Smell Disorders, run by Pamela Youde Nethersole Eastern Hospital at 1 site in Hong Kong.
Trial summary
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… Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Olfaction Disorders, Smell Disorders, Anosmia
- What is being tested?
- Olfactory Training
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- 1 siteHong Kong
- Study dates
- 1 Jul 2022to 30 Jun 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Olfactory dysfunction > 6 months and < 5 years
Who cannot join
- 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
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- Mentally incompetent patients
- <18 years' old
- Pregnancy
- Hypersensitivity to the aromatic substance.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Ka Chung Kwan, FRCSEd(ORL) contact
Hong Kong1 site, 1 recruiting
- Recruiting
Pamela Youde Nethersole Eastern Hospital
Hong Kong
Kai-Chuen, Fergus Wong
About this study
Official title: 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.
Read the 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.
- Conditions
- Olfaction Disorders, Smell Disorders, Anosmia, Hyposmia, Olfactory Impairment, Smell Loss
- Being tested
- Olfactory Training, Control
- Medical subject headings
- Olfaction Disorders, Anosmia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Olfactory TrainingOther
Four aromatic substances will be used (Citrus limon, Eucalyptus radiata, Pelargonium graveolens, Juniperus virginiana)
ControlOther
Normal Saline will be used
| Study group | Role | What they receive |
|---|---|---|
| Treatment arm | Experimental | 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. Receives: Other: Olfactory Training |
| Control arm | Placebo comparator | 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. Receives: Other: Control |
What is being measured
The primary outcome is the main question the study is designed to answer.
Olfactory threshold changes after olfactory training after 3 months
Parameter:
Olfactory threshold using Butanol Threshold Test (BTT)
Measured: 3 months after starting smell training
Olfactory identification score changes after olfactory training after 3 months
Parameter:
Olfactory identification using Smell Identification Test (UPSIT)
Measured: 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)
Measured: 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)
Measured: 3 months after starting smell training
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 May 2022
- Study start1 Jul 2022
- Primary completion30 Jun 2027 (estimated)
- Study completion30 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Olfaction DisordersStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Investigator
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Pamela Youde Nethersole Eastern Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Fergus Wong Kai Chuen, Pamela Youde Nethersole Eastern Hospital
- Investigators
- Kai Chuen Fergus Wong, FRCSEd(ORL), Principal investigator, Pamela Youde Nethersole Eastern Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05364125
- Sponsor's protocol ID
- OlfactoryTrainingHKRCT
- Status last verified
- May 2025
- First submitted
- 14 Apr 2022
- Last updated
- 3 Jun 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Jun 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effect of Olfactory Training on Olfactory Dysfunction Patients in Hong Kong Population
- ClinicalTrials.gov ID
- NCT05364125
- Acronym / sponsor ID
- OlfactoryTrainingHKRCT
- Conditions
- Olfaction Disorders, Smell Disorders, Anosmia, Hyposmia, Olfactory Impairment, Smell Loss
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Pamela Youde Nethersole Eastern HospitalUniversity, hospital or other
- Study start
- 1 Jul 2022 (actual)
- Primary completion
- 30 Jun 2027 (estimated)
- Study completion
- 30 Jun 2027 (estimated)
- First posted
- 6 May 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
- 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.
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 design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Treatment arm | Experimental | Other: Olfactory TrainingOlfactory 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. |
| Control arm | Placebo comparator | Other: ControlSame 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. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Olfactory dysfunction > 6 months and < 5 years
Key exclusion criteria (10 listed)
- History of significant head injury (fracture, ICH)
- History of brain surgery
- History of nasal surgery
- Active nasal disease
- Active neurological disease
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Olfactory TrainingFour aromatic substances will be used (Citrus limon, Eucalyptus radiata, Pelargonium graveolens, Juniperus virginiana) | Other | Treatment arm |
| ControlNormal Saline will be used | Other | Control arm |
Primary outcome
Olfactory threshold changes after olfactory training after 3 months
Time frame: 3 months after starting smell training
Parameter: Olfactory threshold using Butanol Threshold Test (BTT)
Olfactory identification score changes after olfactory training after 3 months
Time frame: 3 months after starting smell training
Parameter: Olfactory identification using Smell Identification Test (UPSIT)
Quality of life changes after olfactory training after 3 months
Time frame: 3 months after starting smell training
Parameter: Subjective quality of life score using Sino-Nasal Outcome Test (SNOT-22)
Taste and smell changes after olfactory training after 3 months
Time frame: 3 months after starting smell training
Parameter: Subjective smell and taste assessment using Visual Analogue Scale (VAS)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Jun 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Ka Chung Kwan, FRCSEd(ORL) contact
Kai Chuen Fergus Wong, FRCSEd(ORL) principal investigator
Pamela Youde Nethersole Eastern Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Olfactory Training in people with Olfaction Disorders and Smell Disorders, run by Pamela Youde Nethersole Eastern Hospital at 1 site in Hong Kong.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 3 Jun 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Hong Kong. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Kai Chuen Fergus Wong, FRCSEd(ORL) (64600771, wkc568@ha.org.hk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Olfactory threshold changes after olfactory training after 3 months (time frame: 3 months after starting smell training). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Jun 2025.