SniffTrain: Effectiveness of Sniff Training in the Treatment of Post-Viral Anosmia

• Sniff Training Kits (Other): This study will test the ability of a structured smell training protocol (called "sniff training") to improved smell function. Participants will be asked to sniff inhaler cartridges containing different USDA GRAS (generally recognized as safe) odors (such as lemon, leather, strawberry, banana, etc). The amount of odor may differ, and odors may or may not be identified on the inhalers. The inhaler cartridge are provided at no charge to study participants in kits that contain four inhalers each.

Primary outcomes

• Improvement in Odor Perception [From enrollment to the end-of-study visit at 52 weeks]: The investigators will use a highly-validated psychophysical smell test (the Sniffin' Sticks Extended Test) to assess changes in olfactory perception and their duration. This test is the primary outcome measure. The resulting TDI score reflects performance on three related test components that measure odor detection Threshold, odor Discrimination, and odor Identification. The scale is 0-48, with higher scores indicating greater function. Investigators will also administer another highly-validated psychophysical smell test, the University of Pennsylvania Smell Identification Test (UPSIT). The score on this 40 point test will not be used to determine the primary outcome but will allow direct comparisons to some other studies that used this measure (higher scores indicated greater function).

Secondary outcomes

• Improvement in social and emotional loneliness [From enrollment to the end-of-study visit at 52 weeks]: Patients with smell loss often experience negative changes in mental health, including increased loneliness. The investigators will use the well-validated De Jong Gierveld short scale questionnaire, composed of six questions, to assess changes in the levels of emotional and social loneliness for each participant. Higher scores on the six-point scale indicates greater loneliness.
• Improvement in quality of life [From enrollment to the end-of-study visit at 52 weeks]: Patients with smell loss often experience negative changes in their quality of life. To assess changes in health-related quality of life, the investigators will administer the SF-12v2 Health Survey questionnaire (or alternatively the Child Health Questionnaire for participants younger than 18 years old). The SF12v2 provides summary, norm-based scores for mental and physical components, with scores of 50 corresponding to the US population average. Higher scores indicate better health-related quality of life.
• Changes in olfactory-associated quality of life [From enrollment to the end-of-study visit at 52 weeks]: Patients with smell loss often experience negative changes in their quality of life. To assess changes in quality of life aspects that have been previously shown to be correlated with olfactory function, the investigators will administer the olfactory-salient Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS). Higher scores on this 51 point scale indicate a greater negative impact of olfactory dysfunction on quality of life.
• Changes in cognitive function [From enrollment to the end-of-study visit at 52 weeks.]: Several studies have suggested that smell training can improve cognitive function. The investigators will administer the Montreal Cognitive Assessment (MoCA) to measure changes in multiple domains of cognitive function in study participants. The MoCA will only be administered to participants ages 14 years old and up. Higher scores on this 30 point scale indicate better cognitive performance.

Sex: All, ages: 10 Years to 60 Years

Inclusion Criteria:

* Aged 10 - 60 years old
* For adults, competent and willing to give informed consent
* For minors, competent and willing to give assent, with informed consent from the parent-guardian
* Willing to undergo study procedures
* Able to follow written and verbal instructions in English
* Be able to report test/questionnaire answers via a computer, tablet, or smartphone interface
* Have a diagnosis of anosmia or hyposmia resulting from a viral infection of the upper respiratory system, with the time since the initial loss of olfactory function > 3 months and < 2 years prior

Exclusion Criteria:

* Aged less than 10 years old, and greater than 60 years old
* Prisoners
* Cognitively impaired individuals

  * Individuals who are deemed to not have the capacity to consent by the study team through observation and direct interaction
  * Individuals 50-60 years old who score <31 on the TICS survey (to rule out potential dementia)
* Non-English speaking subjects
* Pregnant or breastfeeding
* Diseases of the central nervous system (including Alzheimer's disease, multiple sclerosis, Parkinson's disease, Huntington's disease, brain tumors), nasal obstruction (tumors/polyps)
* History of nasal or sinus surgery
* History of a severe head injury/concussion
* History of chronic sinus infections, allergic rhinitis, and active sinonasal disease
* History of radiation therapy to the head or neck (ever)
* Recent chemotherapy (within the last year)
* History of lung/pulmonary disease
* Diagnosis of an olfactory disorder with an etiology other than a viral infection of the upper respiratory system
* Use of the following medications (used within 3 months of enrollment):

  * Oral corticosteroids
  * Topical corticosteroids
  * Biologic agents used in the treatment of nasal/sinus inflammation (dupilumab, omalizumab, mepolizumab, tezepelumab)
  * Theophylline nasal spray
  * Nasal vitamin A
  * Nasal sodium citrate
* A time since loss of olfactory function < 3 months and > 2 years.

• Informed Consent Form: Minor Assent Form (PDF, 2026-06-11)
• Informed Consent Form: Age of Majority Consent Form (PDF, 2026-05-05)
• Informed Consent Form: Adult Consent Form (PDF, 2026-06-11)

• Steven Munger, Principal investigator, University of Virginia