Smell Training for Loss of Smell After COVID-19

(OTTODC19 Trial)

Overseen By Frank Cloutier, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Université du Québec à Trois-Rivières

Disqualifiers: Chronic rhinosinusitis, Neurodegenerative diseases, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 3

Duration: 12 weeks

70 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

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.

Will I have to stop taking my current medications?

The trial information does not specify whether you need to stop taking your current medications.

Is smell training safe for humans?

Research suggests that smell training, used to help regain the sense of smell after COVID-19, is generally safe and does not have significant adverse effects. ^{1 2 3 4 5}

How is smell training different from other treatments for loss of smell after COVID-19?

Smell training is unique because it involves regularly exposing the nose to different scents to help regenerate smell receptors, and it's the only evidence-based treatment specifically for post-viral smell loss. Unlike other treatments, it doesn't involve medication and has no significant side effects. ^{1 2 4 5 6}

What data supports the effectiveness of the treatment Smell Training for Loss of Smell After COVID-19?

Research suggests that olfactory training, which involves regularly smelling different odors, can help improve smell loss after COVID-19. Studies have shown that this method was effective for smell issues caused by other infections, and it is considered a promising option for COVID-19-related smell problems. ^{1 2 5 7 8}

Who Is on the Research Team?

Johannes A Frasnelli, PhD

Principal Investigator

Université du Québec à Trois-Rivières

Are You a Good Fit for This Trial?

This trial is for individuals who had COVID-19 and are now experiencing persistent smell disorders. Participants must be able to give informed consent, understand French, and have internet access with an email.

Inclusion Criteria

I tested positive for COVID-19 and still can't smell properly.

Willing and able to provide written informed consent

I can understand and read French.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

1 visit (in-person)

Initial Meeting

Participants undergo initial olfactory evaluation and receive training instructions

1 day

1 visit (in-person)

Treatment

Participants perform olfactory training with assigned scents for 12 weeks

12 weeks

Self-administered, daily

Final Meeting

Participants undergo final olfactory evaluation after 12 weeks of treatment

1 day

1 visit (in-person)

Follow-up

Participants are monitored for changes in olfactory function post-treatment

4 weeks

What Are the Treatments Tested in This Trial?

Interventions

• Smell training

Trial Overview The study tests olfactory training (smell training) over 12 weeks using two sets of scents to improve the sense of smell after COVID-19. One group uses rose, orange, clove, eucalyptus; another uses cheese, coffee, strawberries, lemon.

How Is the Trial Designed?

Group I: Chemosensory training group 2 Experimental Treatment 1 Intervention

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.

Group II: Chemosensory training group 1 Experimental Treatment 1 Intervention

For 12 weeks, morning and evening, smell four odors namely eucalyptol, phenyl ethanol, Orange, and eugenol, for a total of five minutes per session.

Who Is Running the Clinical Trial?

Université du Québec à Trois-Rivières

Lead Sponsor

Trials

48

Recruited

4,500+

Published Research Related to This Trial

In a study of 52 patients with long COVID-19-related olfactory dysfunction, two-thirds reported subjective improvements in smell and taste, along with a significant reduction in the negative impact on their quality of life.

Olfactory training (OT) showed a modest average effect on smell recovery, but patients who fully complied with the training had a significantly higher chance of clinically meaningful improvement in their olfactory function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Olfactory training in long COVID-19 patients with lasting symptoms including olfactory dysfunction. Fjaeldstad, AW., Ovesen, T., Stankevice, D., et al.[2023]

Olfactory training (OT) significantly improved the sense of smell in COVID-19 patients with persistent olfactory dysfunction, especially in those who adhered to the training protocol, with continued improvements noted up to 12 months after starting OT.

Among 57 patients studied over 18 months, those who fully adhered to OT showed better psychophysical scores compared to those who did not, highlighting the importance of adherence for recovery, although both groups experienced similar rates of olfactory disturbances.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Effectiveness of olfactory training in COVID-19 patients with olfactory dysfunction: a prospective study. Lechien, JR., Vaira, LA., Saussez, S.[2023]

In a pilot study involving 50 participants (25 in the olfactory training group and 25 in the placebo group), olfactory training (OT) did not improve objective olfactory test scores but significantly enhanced participants' subjective sense of smell after 12 weeks.

The study also found that OT reduced the frequency of parosmia (distorted sense of smell) in the intervention group, suggesting potential benefits of OT for individuals experiencing post-COVID-19 olfactory dysfunction.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Olfactory Training Impacts Olfactory Dysfunction Induced by COVID-19: A Pilot Study. Bérubé, S., Demers, C., Bussière, N., et al.[2023]

Olfactory training significantly improved the sense of smell in patients with olfactory dysfunction after COVID-19, with a strong effect size (SMD = 1.0830) indicating that training was effective in enhancing olfactory scores.

Patients who underwent olfactory training during the acute phase of dysfunction (less than 30 days after onset) experienced greater improvements compared to those with chronic dysfunction, suggesting that earlier intervention may lead to better outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The Efficacy of Olfactory Training as a Treatment for Olfactory Disorders Caused by Coronavirus Disease-2019: A Systematic Review and Meta-Analysis. Hwang, SH., Kim, SW., Basurrah, MA., et al.[2023]

Olfactory training (OT) is being investigated as a promising treatment for smell disorders in COVID-19 patients, which can significantly affect their quality of life.

This systematic review will assess the effectiveness and safety of OT, providing crucial evidence to support its use in treating smell dysfunction caused by COVID-19.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Smell disorders in COVID-19 patients: role of olfactory training: A protocol for systematic review and meta-analysis. Zhang, Y., Mei, T., Chen, Y., et al.[2023]

In a pilot study involving 27 patients with persistent olfactory dysfunction due to COVID-19, those treated with a combination of oral corticosteroids and olfactory training showed significant improvement in their sense of smell compared to those who only received olfactory training.

The treatment was found to be safe, with only minimal and transient side effects reported by a few participants, indicating that this approach could be a promising option for patients suffering from long-lasting olfactory loss.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy and safety of oral corticosteroids and olfactory training in the management of COVID-19-related loss of smell. Le Bon, SD., Konopnicki, D., Pisarski, N., et al.[2021]

Olfactory dysfunction (OD) in COVID-19 is linked to damage in sustentacular cells that have ACE-2 receptors, which may lead to prolonged anosmia and increase the risk of neurodegenerative disorders.

Olfactory training (OT) has been shown to be an effective treatment for OD, promoting neural rearrangement and functional connectivity without significant adverse effects, making it a recommended intervention for patients with COVID-induced anosmia.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Olfactory training for olfactory dysfunction in COVID-19: A promising mitigation amidst looming neurocognitive sequelae of the pandemic. Ojha, P., Dixit, A.[2022]

In a clinical trial involving 185 patients with post-COVID-19 olfactory dysfunction, those treated with the anti-inflammatory supplement PEA-LUT alongside olfactory training showed significantly greater improvements in their sense of smell compared to those who received placebo with olfactory training.

The intervention group had a recovery rate of 92%, while only 42% of the control group improved, indicating that PEA-LUT effectively enhances the benefits of olfactory training in restoring olfactory function.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Ultramicronized Palmitoylethanolamide and Luteolin Supplement Combined with Olfactory Training to Treat Post-COVID-19 Olfactory Impairment: A Multi-Center Double-Blinded Randomized Placebo- Controlled Clinical Trial. Di Stadio, A., D'Ascanio, L., Vaira, LA., et al.[2023]

Citations

1. Denmark pubmed.ncbi.nlm.nih.gov

Olfactory training in long COVID-19 patients with lasting symptoms including olfactory dysfunction. [2023]

2. Germany pubmed.ncbi.nlm.nih.gov

Effectiveness of olfactory training in COVID-19 patients with olfactory dysfunction: a prospective study. [2023]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Olfactory Training Impacts Olfactory Dysfunction Induced by COVID-19: A Pilot Study. [2023]

4. United States pubmed.ncbi.nlm.nih.gov

The Efficacy of Olfactory Training as a Treatment for Olfactory Disorders Caused by Coronavirus Disease-2019: A Systematic Review and Meta-Analysis. [2023]

5. United States pubmed.ncbi.nlm.nih.gov

Smell disorders in COVID-19 patients: role of olfactory training: A protocol for systematic review and meta-analysis. [2023]

6. Germany pubmed.ncbi.nlm.nih.gov

Efficacy and safety of oral corticosteroids and olfactory training in the management of COVID-19-related loss of smell. [2021]

7. Australia pubmed.ncbi.nlm.nih.gov

Olfactory training for olfactory dysfunction in COVID-19: A promising mitigation amidst looming neurocognitive sequelae of the pandemic. [2022]

8. United Arab Emirates pubmed.ncbi.nlm.nih.gov

Ultramicronized Palmitoylethanolamide and Luteolin Supplement Combined with Olfactory Training to Treat Post-COVID-19 Olfactory Impairment: A Multi-Center Double-Blinded Randomized Placebo- Controlled Clinical Trial. [2023]