Clinical trial NCT05539560: The Effect of Olfactory Training in Patients With COVID-19 Induced Olfactory Dysfunction
Official title: The Effect of Olfactory Training in Patients With COVID-19 Induced Olfactory Dysfunction - A Randomized Placebo-controlled Clinical Trial
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: COVID-19
Keywords: Olfactory training
Quality of life
Olfactory dysfunction
Covid-19
Parosmia
Lead sponsor: Rigshospitalet, Denmark
Sponsor class: OTHER
First posted: 2022-09-14
Enrollment: 65
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: Aim: The aim is to investigate the effect of olfactory training with essential oils versus olfactory training with placebo-oils in patients with COVID-19 induced olfactory dysfunction

Study design: The study is a placebo-controlled randomized clinical trial with an intervention group and a control group. The intervention group receive four essential oils with scents of orange, lavender, clove, and peppermint. Patients in the control group receive a fragrance kit, consisting of the same containers, but with fragrance-free oils added. Both groups are instructed to smell each of the four oils for 30 seconds in the morning and evening, over a three-month intervention period. Patients are given a diary in which to record their olfactory training. The nurse or medical student instructing the patients in the training and performing the smell and taste tests is blinded.

Study population: Patients referred to the Unit for Sense of Taste and Smell in the Department of Otorhinolaryngology Head \& Neck and Audiology at Rigshospitalet.

Inclusion criteria:

* Impaired sense of taste and smell following COVID-19 \> 3 months
* Hyposmia (16.25-30.5) or anosmia (\<16) assessed by Sniffin' Sticks Olfactory Test for Threshold, Discrimination and Identification (TDI) performed in the Unit for Sense of Taste and Smell with or without parosmia based on medical history
* \> 18 years of age

Exclusion criteria:

* Cause of hyposmia, anosmia or parosmia other than COVID-19
* Does not read or speak Danish
* Lack of compliance to perform daily olfactory training

Procedures:

- TDI-test: To assess patients' sense of smell, the TDI-test with Sniffin' Sticks is used, which is a validated tool with normative data.

Questionnaires:

- 'Taste and Smell Tool for Evaluation' is used to investigate quality of life related to impaired sense of taste and smell.


Eligibility criteria: Inclusion Criteria:

* Olfactory dysfunction caused by COVID-19
* Hyposmia (16.25-30.5) or anosmia (\<16) with or without parosmia assessed by TDI test with Sniffin Sticks performed in the Unit for Sense of Taste and Smell
* \> 18 years of age

Exclusion Criteria:

* Cause of hyposmia, anosmia or parosmia other than COVID-19
* Does not read or speak Danish
* Lack of compliance to perform daily olfactory training

Primary outcomes:
measure: Change in Extended Sniffin' Sticks Test score
timeFrame: 3 months follow-up
Secondary outcomes:
measure: Change in Quality of Life
timeFrame: 3 months follow-up
Other outcomes:
Locations:
city: Copenhagen
country: Denmark
facility: Department of Otorhinolaryngology, Head and Neck Surgery & Audiology, Copenhagen University Hospital
Study officials:
affiliation: Rigshospitalet, Denmark
name: Vibeke G Backer, Professor
role: STUDY_CHAIR
References: