HyposmiaOTTODC19NCT05384561
Olfactory Training as a Treatment for Olfactory Dysfunction Post COVID-19
A study testing Smell training in people with Hyposmia and COVID-19, run by Université du Québec à Trois-Rivières at 1 site in Canada.
Trial summary
Olfactory dysfunction is a defining symptom of COVID-19 infection. Studies have demonstrated improved olfaction in patients with post infectious olfactory dysfunction after an olfactory training (OT). Read more about this study
- Who is it for?
- Ages 18 years and older
- What is being tested?
- Smell training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 70 participants
- Where
- 1 siteCanada
- Study dates
- 31 May 2022to Sep 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 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Patient diagnosed positive for COVID-19 with persistent olfactory dysfunction
- Willing and able to provide written informed consent
- Understand and read the French language
- Have an internet connection and a working email address
Who cannot join
- Anosmia and hyposmia pre-covid-19
- Be known chronic rhinosinusitis with or without nasal polyposis
- Have received radiotherapy or chemotherapy for Head and Neck Tumors
- Have a diagnosis of Alzheimer's, Parkinson's, multiple sclerosis or any other neurodegenerative disease 5. Have a brain tumor or ENT diagnosis 6. History of naso-sinus surgery; 7. History of traumatic brain injury
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Canada1 site, 1 recruiting
- Recruiting
Université du Québec à Trois-Rivières
Trois-Rivières, Quebec, G8Z 4M3
Frank Cloutier, PhD, 18193765011 ext. 3360, frank.cloutier@uqtr.ca
Simon Bérubé, Med Student, simon.berube.1@umontreal.ca
About this study
Official title: L'entraînement Olfactif Comme Traitement de la Dysfonction Olfactive Post COVID-19
Olfactory dysfunction is a defining symptom of COVID-19 infection. Studies have demonstrated improved olfaction in patients with post infectious olfactory dysfunction after an olfactory training (OT). The aim of this study is to assess the clinical outcomes of olfactory training (12 weeks) therapy in the treatment of persistent olfactory dysfunctions after COVID-19. Specially, we aim to compare the effectiveness of two different olfactory training (different odors).
A group will train themselves with 4 scents (rose, orange, clove and eucalyptus) and another group with 4 different scents (cheese, coffee, strawberries and lemon). Olfaction sensory evaluation will be performed by using different olfaction tests (Sniffin' Sticks and UPSIT) and complete questionnaires to assess olfactory perception and particularly parosmia and phantosmia.
Read the detailed description
Patients who meet the criteria, who have agreed to participate in this research project and sign the consent form will be placed in one of the following two groups:
● Experimental group (olfactory training)
- Initial meeting: Each participant will be asked for a session of approximately 1:30 h which will take place in a ventilated room in the laboratory of Dr. Johannes Frasnelli at UQTR. During the hour preceding this evaluation, subjects will be asked not to smoke, eat or drink anything other than water and not to wear perfume. A research assistant will be responsible for completing the various tests. During this meeting, the following tests will be done:
- Data collection (case report form): medical and socio-demographic questionnaire that will be used for data analysis.
- A nasal obstruction criterion scale - NOSE
- A subjective questionnaire on the impact of OD on quality of life - sQOD-NS
- Chemosensory Dysfunction Home Test - TMSC
- The UPSIT 40 test
- The Sniffin' Sticks test
- Test to assess the manifestation of parosmia and phantosmia
- Teaching on the olfactory rehabilitation kit and explanation of the training protocol.
- Treatment (12 weeks): Following the initial meeting, patients can begin training: ■ Participants will bring their training kit with them following the olfactory evaluation.
- Final meeting: After 12 weeks of treatment, an appointment will be scheduled with the participant. The olfactory evaluation will be done as described in the initial meeting. During the hour preceding this evaluation, subjects will be asked not to smoke, eat or drink anything other than water and not to wear perfume. A research assistant will be responsible for administering the various tests. During this meeting, the following tests will be done:
- A subjective questionnaire on the impact of OD on quality of life - sQOD-NS
- Chemosensory Dysfunction Home Test - TMSC
- The UPSIT 40 test
- The Sniffin' Sticks test
- Test to assess the manifestation of parosmia and phantosmia
- Conditions
- Hyposmia, COVID-19, Parosmia, Anosmia, SARS-CoV-2 Infection
- Being tested
- Smell training
- Keywords
- Olfactory training, Chemosensory impairments, Persistent smell impairment
- Medical subject headings
- Anosmia, COVID-19, Olfaction Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Smell trainingOther
Also called Chemosensory training group
For 12 weeks, morning and evening, smell four different odors or four odorless substances for a total of five minutes per session.
| Study group | Role | What they receive |
|---|---|---|
| Chemosensory training group 1 | Experimental | For 12 weeks, morning and evening, smell four odors namely eucalyptol, phenyl ethanol, Orange, and eugenol, for a total of five minutes per session. Receives: Other: Smell training |
| Chemosensory training group 2 | Experimental | For 12 weeks, morning and evening, smell four odors namely coffee aroma, cheese aroma, strawberries, and limon, for a total of five minutes per session. Receives: Other: Smell training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Changes from baseline in olfactory score on the University of Pennsylvania Identification Test (UPSIT) [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
The UPSIT includes 4 odor-impregnated booklets that contain 10 forced-choice multiple choice questions each for participants to scratch-and-sniff to identify various odors and is a commercially available test. Normosmia is defined as ≥34 for males and ≥35 for females, and a change of 4 points or more from baseline indicates a clinically meaningful result.
Measured: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
Changes from baseline in olfactory score on the Sniffin's Sticks test
Sniffin' Sticks test and Taste strips: Sniffin' Sticks test (Burghardt®, Wedel, Germany) is a psychophysical test. It allows semi-objective assessment of the patient's olfactory performance by means of 3 subtests: threshold test, identification test and discrimination test. The Sniffin' Sticks Olfactory Test Kits contain pen like bodies as, for example, in pens used to write on flipcharts or whiteboards.These pen-like bodies, however, contain a fibre stick which is filled with scents. For testing, the cap should be removed so the patient can smell on the tip of the pen.
Measured: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
n-house test for chemosensory dysfunction (TMSC)
The TMSC is a 55-item questionnaire evaluating the three chemical senses: olfaction, taste and the trigeminal sense. First, questions with a 10-point visual analog scale make a subjective self-assessment of each of the three senses. Multiple-choice questions establish the precise characteristics of the dysfunctions of each of the senses if they are present. Secondly, a psychophysical test is administered remotely using substances typical of North American cuisines. Substances are first sniffed (peanut butter, jam, vinegar, coffee) then tasted (peanut butter, jam, salt water (1 tsp/250mL), sugar water (3 tsp/250mL)). The perceived intensity of each of the substances is reported each time on a visual analogue scale of 10 points.
Measured: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
Parosmia and phantosmia assessment test
This test has a first part with four questions that aim to assess the presence of parosmia or phastosmia. Patients who have reported parosmia or phantosmia will be asked to complete a second part with six questions focusing on the quality of their olfactory distortion.
Measured: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
The abridged version of the Questionnaire of Olfactory Disorders - Negative Statements (sQOD-NS)
The sQOD-NS is a validated questionnaire that measures the quality of life specific to olfactory functions. The questionnaire measures 7 items with a 4-point Likert scale.
Measured: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
Secondary outcomes (1)
Nasal Obstruction Symptom Evaluation (NOSE)
A visual analog scale (scale from "not a problem" to "severe problem") is used by participants to assess their nasal obstruction. The duration of this test is approximately 2 minutes.
Measured: Measurement will be taken at time zero (pre-intervention)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 May 2022
- Study start31 May 2022
- Primary completionSep 2027 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HyposmiaStudies 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
- Participant
- Enrolment
- 70 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Université du Québec à Trois-Rivières
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Johannes A Frasnelli, PhD, Principal investigator, Université du Québec à Trois-Rivières
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05384561
- Sponsor's protocol ID
- OTTODC192022JFUQTR
- Acronym
- OTTODC19
- Status last verified
- Jul 2026
- First submitted
- 19 May 2022
- Last updated
- 31 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- L'entraînement Olfactif Comme Traitement de la Dysfonction Olfactive Post COVID-19
- ClinicalTrials.gov ID
- NCT05384561
- Acronym / sponsor ID
- OTTODC19 / OTTODC192022JFUQTR
- Conditions
- Hyposmia, COVID-19, Parosmia, Anosmia, SARS-CoV-2 Infection
- Keywords
- Olfactory training, Chemosensory impairments, Persistent smell impairment
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 70 participants (estimated)
- Lead sponsor
- Université du Québec à Trois-RivièresUniversity, hospital or other
- Study start
- 31 May 2022 (actual)
- Primary completion
- Sep 2027 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 20 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.
Olfactory dysfunction is a defining symptom of COVID-19 infection. Studies have demonstrated improved olfaction in patients with post infectious olfactory dysfunction after an olfactory training (OT). The aim of this study is to assess the clinical outcomes of olfactory training (12 weeks) therapy in the treatment of persistent olfactory dysfunctions after COVID-19. Specially, we aim to compare the effectiveness of two different olfactory training (different odors).
A group will train themselves with 4 scents (rose, orange, clove and eucalyptus) and another group with 4 different scents (cheese, coffee, strawberries and lemon). Olfaction sensory evaluation will be performed by using different olfaction tests (Sniffin' Sticks and UPSIT) and complete questionnaires to assess olfactory perception and particularly parosmia and phantosmia.
Detailed description
Patients who meet the criteria, who have agreed to participate in this research project and sign the consent form will be placed in one of the following two groups:
● Experimental group (olfactory training)
- Initial meeting: Each participant will be asked for a session of approximately 1:30 h which will take place in a ventilated room in the laboratory of Dr. Johannes Frasnelli at UQTR. During the hour preceding this evaluation, subjects will be asked not to smoke, eat or drink anything other than water and not to wear perfume. A research assistant will be responsible for completing the various tests. During this meeting, the following tests will be done:
- Data collection (case report form): medical and socio-demographic questionnaire that will be used for data analysis.
- A nasal obstruction criterion scale - NOSE
- A subjective questionnaire on the impact of OD on quality of life - sQOD-NS
- Chemosensory Dysfunction Home Test - TMSC
- The UPSIT 40 test
- The Sniffin' Sticks test
- Test to assess the manifestation of parosmia and phantosmia
- Teaching on the olfactory rehabilitation kit and explanation of the training protocol.
- Treatment (12 weeks): Following the initial meeting, patients can begin training: ■ Participants will bring their training kit with them following the olfactory evaluation.
- Final meeting: After 12 weeks of treatment, an appointment will be scheduled with the participant. The olfactory evaluation will be done as described in the initial meeting. During the hour preceding this evaluation, subjects will be asked not to smoke, eat or drink anything other than water and not to wear perfume. A research assistant will be responsible for administering the various tests. During this meeting, the following tests will be done:
- A subjective questionnaire on the impact of OD on quality of life - sQOD-NS
- Chemosensory Dysfunction Home Test - TMSC
- The UPSIT 40 test
- The Sniffin' Sticks test
- Test to assess the manifestation of parosmia and phantosmia
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Chemosensory training group 1 | Experimental | Other: Smell trainingFor 12 weeks, morning and evening, smell four odors namely eucalyptol, phenyl ethanol, Orange, and eugenol, for a total of five minutes per session. |
| Chemosensory training group 2 | Experimental | Other: Smell trainingFor 12 weeks, morning and evening, smell four odors namely coffee aroma, cheese aroma, strawberries, and limon, for a total of five minutes per session. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Patient diagnosed positive for COVID-19 with persistent olfactory dysfunction
- Willing and able to provide written informed consent
- Understand and read the French language
- Have an internet connection and a working email address
Key exclusion criteria (4 listed)
- Anosmia and hyposmia pre-covid-19
- Be known chronic rhinosinusitis with or without nasal polyposis
- Have received radiotherapy or chemotherapy for Head and Neck Tumors
- Have a diagnosis of Alzheimer's, Parkinson's, multiple sclerosis or any other neurodegenerative disease 5. Have a brain tumor or ENT diagnosis 6. History of naso-sinus surgery; 7. History of traumatic brain injury
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 |
|---|---|---|
| Smell trainingAlso: Chemosensory training groupFor 12 weeks, morning and evening, smell four different odors or four odorless substances for a total of five minutes per session. | Other | Chemosensory training group 1, Chemosensory training group 2 |
Primary outcome
Changes from baseline in olfactory score on the University of Pennsylvania Identification Test (UPSIT) [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
Time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
The UPSIT includes 4 odor-impregnated booklets that contain 10 forced-choice multiple choice questions each for participants to scratch-and-sniff to identify various odors and is a commercially available test. Normosmia is defined as ≥34 for males and ≥35 for females, and a change of 4 points or more from baseline indicates a clinically meaningful result.
Changes from baseline in olfactory score on the Sniffin's Sticks test
Time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
Sniffin' Sticks test and Taste strips: Sniffin' Sticks test (Burghardt®, Wedel, Germany) is a psychophysical test. It allows semi-objective assessment of the patient's olfactory performance by means of 3 subtests: threshold test, identification test and discrimination test. The Sniffin' Sticks Olfactory Test Kits contain pen like bodies as, for example, in pens used to write on flipcharts or whiteboards.These pen-like bodies, however, contain a fibre stick which is filled with scents. For testing, the cap should be removed so the patient can smell on the tip of the pen.
n-house test for chemosensory dysfunction (TMSC)
Time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
The TMSC is a 55-item questionnaire evaluating the three chemical senses: olfaction, taste and the trigeminal sense. First, questions with a 10-point visual analog scale make a subjective self-assessment of each of the three senses. Multiple-choice questions establish the precise characteristics of the dysfunctions of each of the senses if they are present. Secondly, a psychophysical test is administered remotely using substances typical of North American cuisines. Substances are first sniffed (peanut butter, jam, vinegar, coffee) then tasted (peanut butter, jam, salt water (1 tsp/250mL), sugar water (3 tsp/250mL)). The perceived intensity of each of the substances is reported each time on a visual analogue scale of 10 points.
Parosmia and phantosmia assessment test
Time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
This test has a first part with four questions that aim to assess the presence of parosmia or phastosmia. Patients who have reported parosmia or phantosmia will be asked to complete a second part with six questions focusing on the quality of their olfactory distortion.
The abridged version of the Questionnaire of Olfactory Disorders - Negative Statements (sQOD-NS)
Time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)
The sQOD-NS is a validated questionnaire that measures the quality of life specific to olfactory functions. The questionnaire measures 7 items with a 4-point Likert scale.
1 secondary outcome
Nasal Obstruction Symptom Evaluation (NOSE)
Time frame: Measurement will be taken at time zero (pre-intervention)
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 31 Jul 2026.
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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.
Johannes A Frasnelli, PhD principal investigator
Université du Québec à Trois-Rivières
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Smell training in people with Hyposmia and COVID-19, run by Université du Québec à Trois-Rivières at 1 site in Canada.
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 4 inclusion and 4 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 31 Jul 2026. 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 Canada. 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. 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 Johannes A Frasnelli, PhD (18193765011 ext. 3589, johannes.a.frasnelli@uqtr.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Changes from baseline in olfactory score on the University of Pennsylvania Identification Test (UPSIT) [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention) (time frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention)). The study lists 5 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 31 Jul 2026.