Visual-OLfactory Training in Participants With COVID-19 Resultant Loss of Smell (VOLT)
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ClinicalTrials.gov Identifier: NCT04710394 |
Recruitment Status :
Completed
First Posted : January 14, 2021
Last Update Posted : June 21, 2022
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Olfactory dysfunction is a defining symptom of COVID-19 infection. As the number of total, confirmed COVID-19 cases approached 19 million in the United States, it is estimated that there will be 250,000 to 500,000 new cases of chronically diminished smell (hyposmia) and loss of smell (anosmia) this year. Olfactory dysfunction is proposed to worsen numerous common co-morbidities in patients and has been shown to lead to a decreased quality of life. There are very few effective treatments for hyposmia or anosmia, and there is no gold standard of treatment.
One proposed treatment option is smell training, which has shown promising yet variable results in a multitude of studies. It garners its theoretical basis from the high degree of neuroplasticity within the olfactory system, both peripherally and centrally. However, due to a relative inadequacy of proper studies on olfactory training, it is unknown what the most efficacious method in which to undergo the training is. This study proposes two novel procedural modifications to smell training in an attempt to enhance its efficacy. The investigators propose using a bimodal visual-olfactory approach, rather than relying on olfaction alone, during smell training, as well as using patient-preferred scents in the training that are identified as important by the study participant, rather than pre-determined scents with inadequate scientific backing. The investigators hypothesize that by utilizing bimodal visual-olfactory training and patient-selected scents, the olfactory training will be more efficacious and more motivating for participants.
Condition or disease | Intervention/treatment | Phase |
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Anosmia Covid19 Ageusia Hyposmia Hypogeusia SARS-CoV-2 Infection COVID-19 Pandemic | Behavioral: Smell Training | Not Applicable |

Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 240 participants |
Allocation: | Randomized |
Intervention Model: | Factorial Assignment |
Intervention Model Description: | Two-by-two factorial interventional study design will lend to achieving the study aims. Participants meeting eligibility criterion will be randomized to one of four arms:
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Masking: | Double (Participant, Care Provider) |
Primary Purpose: | Treatment |
Official Title: | Efficacy of Bimodal Visual-Olfactory Training in Participants With COVID-19 Resultant Hyposmia or Anosmia Using Participant-Preferred Scents |
Actual Study Start Date : | January 11, 2021 |
Actual Primary Completion Date : | March 11, 2022 |
Actual Study Completion Date : | March 11, 2022 |

Arm | Intervention/treatment |
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Active Comparator: Unimodal Olfactory Training with Conventional Odors
Participants will undergo smell training without a visual component, and train using 4 pre-determined scents: rose, lemon, eucalyptus, and clove.
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Behavioral: Smell Training
Participants will be provided with 4 labeled jars, each containing an odor pre-impregnated cotton pad. Participants will sniff each scent for 10 seconds, twice daily, once in the morning and once in evening. The participant will take 30 seconds of rest between each scent. All participants will undergo this smell training regimen for 12 weeks.
Other Name: Olfactory Training |
Experimental: Unimodal Olfactory Training with Patient-Preferred Odors
Participants will undergo smell training without a visual component, and undergo an odor selection process in which they choose four scents to train with that they identify as important. A total of 24 scents will be included for patients to select from, including: Lemon, Orange, Grapefruit, Lime, Eucalyptus, Peppermint, Spearmint, Tea Tree, Rose, Lavender, Jasmine, Geranium, Frankincense, Cedarwood, Juniper, Sandalwood, Black Pepper, Oregano, Rosemary, Clove, Vanilla, Coffee, Cinnamon, Nutmeg.
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Behavioral: Smell Training
Participants will be provided with 4 labeled jars, each containing an odor pre-impregnated cotton pad. Participants will sniff each scent for 10 seconds, twice daily, once in the morning and once in evening. The participant will take 30 seconds of rest between each scent. All participants will undergo this smell training regimen for 12 weeks.
Other Name: Olfactory Training |
Experimental: Bimodal Visual, Olfactory Training with Conventional Odors
Participants will undergo smell training while simultaneously focusing on a picture of the odor, and train using 4 pre-determined scents: rose, lemon, eucalyptus, and clove.
|
Behavioral: Smell Training
Participants will be provided with 4 labeled jars, each containing an odor pre-impregnated cotton pad. Participants will sniff each scent for 10 seconds, twice daily, once in the morning and once in evening. The participant will take 30 seconds of rest between each scent. All participants will undergo this smell training regimen for 12 weeks.
Other Name: Olfactory Training |
Experimental: Bimodal Visual, Olfactory Training with Patient-Preferred Odors
Participants will undergo smell training while simultaneously focusing on a picture of the odor, and undergo an odor selection process in which they choose four scents to train with that they identify as important. A total of 24 scents will be included for patients to select from, including: Lemon, Orange, Grapefruit, Lime, Eucalyptus, Peppermint, Spearmint, Tea Tree, Rose, Lavender, Jasmine, Geranium, Frankincense, Cedarwood, Juniper, Sandalwood, Black Pepper, Oregano, Rosemary, Clove, Vanilla, Coffee, Cinnamon, Nutmeg.
|
Behavioral: Smell Training
Participants will be provided with 4 labeled jars, each containing an odor pre-impregnated cotton pad. Participants will sniff each scent for 10 seconds, twice daily, once in the morning and once in evening. The participant will take 30 seconds of rest between each scent. All participants will undergo this smell training regimen for 12 weeks.
Other Name: Olfactory Training |
- University of Pennsylvania Smell 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.
- Clinical Global Impression Severity (CGI-S) Scale [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention) ]The CGI-S is a subjective rating scale in which a participant can rate the severity of their dysfunction. The scale is rated from 1-7 with 1 being normal sense of smell, 4 being moderate loss of smell, and 7 being complete loss of smell. Each rating has a definition to better elucidate what any particular rating might mean, so as to decrease variability between patient responses with the same subjective level of dysfunction or improvement.
- Clinical Global Impression Improvement (CGI-I) Scale [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention) ]The CGI-I is a subjective rating scale in which a participant can rate the rate the improvement (or lack thereof) of their dysfunction after smell training. The scale is rated from 1-7 with 1 being very much improved sense of smell, 4 being no change in sense of smell, and 7 being very much worse sense of smell. Each rating has a definition to better elucidate what any particular rating might mean, so as to decrease variability between patient responses with the same subjective level of dysfunction or improvement.
- Olfactory Dysfunction Outcomes Rating (ODOR) [ Time Frame: Measurement will be taken at time zero (pre-intervention) and 12 weeks (post-intervention) ]A 28-item health-related quality of life instrument specific for olfactory dysfunction developed by Dr. Jake Lee in Dr. Jay F. Piccirillo's lab at Washington University.

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Ages Eligible for Study: | 18 Years to 70 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Subjective or clinically diagnosed olfactory dysfunction of 3 months duration or longer initially diagnosed within 2 weeks of a COVID-19 infection
Exclusion Criteria:
- Diagnosed olfactory dysfunction due to head trauma
- Chronic rhinosinusitis
- Congenital olfactory dysfunction
- Nasal polyps
- Neurodegenerative disorders (for example, Alzheimer or Parkinson Disease)
- Pre-Assessment UPSIT score ≥34 for males and ≥35 for females
- Pregnant
- Inability to read, write, and understand English
- Inability to perform home olfactory training (for example, due to limited access to internet)
- Residence outside of the the United States of America
- Previously conducting smell training

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04710394
United States, Missouri | |
Washington University School of Medicine in Saint Louis | |
Saint Louis, Missouri, United States, 63108 |
Principal Investigator: | Jay F. Piccirillo, M.D., FACS | Washington University School of Medicine |
Publications:
Responsible Party: | Washington University School of Medicine |
ClinicalTrials.gov Identifier: | NCT04710394 |
Other Study ID Numbers: |
7011897206 |
First Posted: | January 14, 2021 Key Record Dates |
Last Update Posted: | June 21, 2022 |
Last Verified: | June 2022 |
Individual Participant Data (IPD) Sharing Statement: | |
Plan to Share IPD: | Yes |
Plan Description: | Data and research resources generated from this clinical trial will be made available by request, while safeguarding the privacy of participants in accordance with NIH policy and HIPAA guidelines. The data to be shared will include information about the project, protocol, data dictionary, and the final individual de-identified research subject data. These data will include the responses to the baseline and post-intervention Olfactory Dysfunction Outcomes Rating (ODOR), Clinical Global Impression Severity (CGI-S) Scale , University of Pennsylvania Smell Identification Test (UPSIT), post-intervention Clinical Global Impression Improvement (CGI-I) Scale, and treatment assignment. |
Supporting Materials: |
Study Protocol Statistical Analysis Plan (SAP) |
Time Frame: | The data will be made available within 12 months of the completion date of the research project, for 2 subsequent years. |
Access Criteria: | Data access will be arranged through a data-sharing agreement, which will indicate the criteria for data access, documentation of IRB approval from requestor's institution, incorporation of appropriate privacy and confidentiality standards to ensure data security at the recipient site, and prohibit manipulation of data for the purposes of identifying subjects or redistribution to third parties. Data access will be managed by the Research Compliance and Recruitment Coordinator, and data maintenance will be managed by the Study Biostatistician. |
URL: | http://otolaryngologyoutcomesresearch.wustl.edu/ |
Studies a U.S. FDA-regulated Drug Product: | No |
Studies a U.S. FDA-regulated Device Product: | No |
Anosmia Loss of Smell Loss of Taste Hyposmia |
Ageusia Covid-19 SARS-CoV-2 |
COVID-19 Anosmia Ageusia Pneumonia, Viral Pneumonia Respiratory Tract Infections Infections Virus Diseases Coronavirus Infections Coronaviridae Infections |
Nidovirales Infections RNA Virus Infections Lung Diseases Respiratory Tract Diseases Olfaction Disorders Sensation Disorders Neurologic Manifestations Nervous System Diseases Taste Disorders |