Olfactory Training on Smell Dysfunction Patients in HK

NCT05364125 | Recruiting

• 1 other identifier: OlfactoryTrainingHKRCT
• Study Type: interventional
• Target: 80
• Locations: 1 country
• Sites: 1

Brief 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 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.

Conditions

Olfaction Disorders; Smell Disorders; Anosmia; Hyposmia; Olfactory Impairment; Smell Loss; Smell Dysfunction

Outcome Measures

Primary Outcomes (4)

• 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

Study Arms (2)

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.

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.

Other: Control

Interventions

Olfactory Training OTHER

Four aromatic substances will be used (Citrus limon, Eucalyptus radiata, Pelargonium graveolens, Juniperus virginiana)

Treatment arm

Control OTHER

Normal Saline will be used

Control arm

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Olfactory dysfunction \> 6 months and \< 5 years

You may not qualify if:

• 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.

Sponsors & Collaborators

• Pamela Youde Nethersole Eastern Hospital: lead

Study Sites (1)

Pamela Youde Nethersole Eastern Hospital

Hong Kong, Hong Kong

RECRUITING

MeSH Terms

Conditions

Olfaction Disorders; Anosmia

Interventions

Olfactory Training

Condition Hierarchy (Ancestors)

Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Therapeutics

Study Officials

• Kai Chuen Fergus Wong, FRCSEd(ORL)

  Pamela Youde Nethersole Eastern Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Kai Chuen Fergus Wong, FRCSEd(ORL)

CONTACT

64600771; wkc568@ha.org.hk

Ka Chung Kwan, FRCSEd(ORL)

CONTACT

64600056

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: INVESTIGATOR
• Masking Details: Randomly assigned by computer into treatment group and control group
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Consultant

Study Record Dates

• First Submitted: April 14, 2022
• First Posted: May 6, 2022
• Study Start: July 1, 2022
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027
• Last Updated: June 3, 2025

Record last verified: 2025-05

Data Sharing

• IPD Sharing: Will not share

Locations

HK (1)