Association Between Smell Training and Quality of Life in Patients With Impaired Sense of Smell Following COVID-19 (SMELLT2022)

Association Between Olfactory Training and Quality of Life in Patients With Impaired Sense of Taste and Smell Following COVID-19

Aim: The aim is to investigate whether guided systematic olfactory training with essential oils to improve impaired sense of smell following COVID-19, can improve patients' quality of life.

Hypothesis: The impaired quality of life in patients with impaired sense of smell following COVID-19, can be significantly improved in patients performing olfactory training with essential oils, compared to patients performing olfactory training with placebo oils.

Study design: The study is a 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 (15-30) or anosmia (<15) assessed by Sniffin' Sticks Olfactory Test for Threshold, Discrimination and Identification (TDI) performed in the Unit for Sense of Taste and Smell or medical assessment of parosmia based on medical history
• > 18 years of age

Exclusion criteria:

• Cause of hyposmia, anosmia or parosmia other than COVID-19
• Impaired sense of taste and smell >24 months
• 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.
• Taste test: To assess patients' sense of taste, taste sprays with the basic tastes are used.

Questionnaires:

• 'Taste and Smell Tool for Evaluation' is used to investigate quality of life related to impaired sense of taste and smell.
• 'Major Depression Inventory' (MDI) is used in the project to assess whether the patient is depressed and to make a possible assessment of the severity of depression.

Study Overview

• Status: Recruiting
• Conditions: COVID-19
• Intervention / Treatment: Other: Olfactory training with essential oils; Other: Olfactory training with fragrance-free oils

• Study Type: Interventional
• Enrollment (Estimated): 150
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Vibeke Backer, Professor; Phone Number: +45 35456033; Email: nina.vibeke.backer@regionh.dk
• Study Contact Backup: Name: Ditte G Gertz Mogensen, PhD-student; Phone Number: +45 35457508; Email: ditte.gertz.mogensen@regionh.dk

Study Locations

• Denmark
  • Copenhagen, Denmark, 2100
    • Recruiting
    • Department of Otorhinolaryngology, Head and Neck Surgery & Audiology, Copenhagen University Hospital
    • Contact: Ditte Gertz Mogensen, PhD-student; Phone Number: +45 35457508; Email: ditte.gertz.mogensen@regionh.dk
    • Contact: Vibeke Backer, Professor; Phone Number: +45 3545 6033; Email: nina.vibeke.backer@regionh.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Olfactory dysfunction caused by COVID-1
• Hyposmia (15-30) or anosmia (<15) assessed by TDI test with Sniffin Sticks performed in the Unit for Sense of Taste and Smell or medical assessment of 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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Intervention group; Olfactory training twice a day with essential oils	Other: Olfactory training with essential oils; Olfactory training twice daily with essential oils from Urtegaarden Aps with scents of orange, lavender, clove and peppermint. The olfactory training is performed every morning and evening, by smelling each of the oils for 30 seconds.; Other Names: Urtegaarden ApS Essential Oils
Placebo Comparator: Control group; Olfactory training twice a day with fragrance-free oils	Other: Olfactory training with fragrance-free oils; Olfactory training twice daily with fragrance-free oils from Urtegaarden Aps in the same four containers as the intervention group. The olfactory training is performed every morning and evening, by smelling each of the oils for 30 seconds.; Other Names: Urtegaarden ApS Essential Oils (Fragrance-free custom made)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Quality of Life	Change in Quality of Life measured by the questionnaire Taste and Smell Tool for Evaluation. The minimum score is 21 and the maximum score is 105. A higher score means worse outcome (quality of life).	3 months follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Extended Sniffin' Sticks Test score	Change in TDI score measured by Burghart Extended Sniffin' Sticks Test (TDI test). The TDI test, consists of a threshold test, a discrimination test, and an identification test. The results of the three subtests makes a total TDI score, where the minimum score is 1 and the maximum score is 48. A score >30 indicates normal olfactory function, a score between 15-30 indicates hyposmia and a score <15 indicates anosmia in the form of severely impaired or complete loss of olfaction.	3 months follow-up
Change in Major Depression Inventory score (MDI)	Change in MDI score measured by Major Depression Inventory. The theoretical sum score ranges from 0 (no depression) to 50 (maximum depression).	3 months follow-up

Collaborators and Investigators

• Sponsor: Ditte Gertz Mogensen
• Investigators: Study Chair: Vibeke G Backer, Professor, Rigshospitalet, Denmark

Study record dates

Study Major Dates

• Study Start (Actual): June 29, 2022
• Primary Completion (Estimated): April 30, 2024
• Study Completion (Estimated): September 30, 2025

Study Registration Dates

• First Submitted: September 2, 2022
• First Submitted That Met QC Criteria: September 13, 2022
• First Posted (Actual): September 14, 2022

Study Record Updates

• Last Update Posted (Estimated): November 16, 2023
• Last Update Submitted That Met QC Criteria: November 15, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: Quality of life; Covid-19; Olfactory dysfunction; Olfactory training
• Additional Relevant MeSH Terms: Coronavirus Infections; Coronaviridae Infections; Nidovirales Infections; RNA Virus Infections; Virus Diseases; Infections; Respiratory Tract Infections; Respiratory Tract Diseases; Pneumonia, Viral; Pneumonia; Lung Diseases; COVID-19
• Other Study ID Numbers: 2022-ENT-1-olfactory

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No