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SCENT for Long COVID: Smell Dysfunction Study

This study is for people experiencing ongoing smell loss or changes (like diminished, distorted, or absent smell) due to Long COVID. It's testing two at-home treatments: Trigeminal Nerve Stimulation (TNS), which uses gentle electrical stimulation on the forehead to improve smell, and Active Smell Training, which involves sniffing various strong scents and doing smell-related tasks. A comparison group will do Placebo Smell Training with weaker scents. The study aims to see how well these treatments improve your sense of smell and how you perceive odors after 4 and 12 weeks. You can join if you are 18-65, have had COVID-related smell loss for at least one month, had a normal sense of smell before COVID, and haven't tried these treatments before. The study status is currently unclear.

Study design
This is an interventional study planning to enroll 145 participants. It compares two active treatments (Trigeminal Nerve Stimulation and Active Smell Training) to a placebo smell training.
What's involved
You will conduct daily at-home treatment sessions, attend three in-person study visits at MUSC, and complete electronic questionnaires over 12 weeks.
Compensation
Not stated in the trial record.
Follow-up
Your smell function will be measured at 4 weeks, 12 weeks, and again at six months after the start of the trial.

AI-generated from the public study record. Only the study team can confirm whether you're eligible — confirm details with them before making decisions.

NCT05855369

Study of Chemosensory Enhancement Through Neuromodulation Training (SCENT for Long COVID)

Recruiting
PHASE2Ages 18–65InterventionalTreatment
Medical University of South Carolina
~145 participants
Updated 2026-04-02 on ClinicalTrials.gov
What's tested:Trigeminal Nerve Stimulation (TNS)Active Smell Training (ST)Placebo Smell Training (PBO)

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Change in Psychophysical Olfactory Function from Baseline to 4 and 12 Weeks
Measured over 2 times: 4 weeks, 12 weeks
+4 more outcomes measured

Conditions

Smell Dysfunction
Olfactory Disorder
Long COVID

Explore related trials

Post-Acute Sequelae of COVID-19Smell Dysfunction

NCT05855369

Where you'd take part

This study runs at 1 site. They're the same protocol — you choose where, and that choice sets who your contact draft is addressed to.

  • Medical University of South Carolina

    Charleston, South Carolinastudy coordinator listed

    Recruiting

Sites open and close at different times, so the status above is per site — it can differ from the study's overall status.

Who to contact

Bernadette M. Cortese, Ph.D.
[email protected]
843-792-6922
Email the study team

Opens a ready-to-send draft in your own email app — review before sending.

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Eligibility criteria

Inclusion

treatment-seeking for COVID-related persistent SL (anosmia, hyposmia, phantosmia or parosmia)
at least 1-month from SARS-coV-2 PCR-positive and/or rapid home-positive tests
normal sense of smell prior to COVID
naïve to both smell training (ST) and trigeminal nerve stimulation (TNS)
able to comprehend English and provide informed consent

Exclusion

history of head injury (e.g. sport, accident, combat blast)
sinonasal condition (e.g. upper respiratory infection, rhinosinusitis, polyps)
neurological disorder (e.g. epilepsy, neurodegenerative disorder, narcolepsy)
serious mental illness (e.g. schizophrenia, bipolar, or other psychotic disorder)
suicidal ideation within the last month
current (≤6 months) heavy cigarette smoker (heavy defined as ≥ 10 pack-years)
oral/nasal steroids or other intranasal medications within the last month
immunomodulatory medications
pregnant or trying to become pregnant

What this trial measures

  • Change in Psychophysical Olfactory Function from Baseline to 4 and 12 Weeks2 times: 4 weeks, 12 weeks

    Sniffin' Sticks (Bughardt Messtechnik, Wedel Germany) will be used to determine odor threshold (T), odor discrimination (D), and odor identification (I), each on 16-point scales, and summed for a total TDI score. Higher scores indicate better function.

  • Change in Perceived Intensity of Odorants from Baseline to 4 and 12 Weeks2 times: 4 weeks, 12 weeks

    Perceived intensity on 100-mm visual analog scales with anchor points: 0="imperceptible" to 100="extremely intense" will be rated for suprathreshold concentrations of PEA, vanilla, eugenol, and eucalyptus.

  • Change in Perceived Hedonics of Odorants from Baseline to 4 and 12 Weeks2 times: 4 weeks, 12 weeks

    Perceived hedonics on 100-mm visual analog scales with anchor points: 0="extremely unpleasant" to 100="extremely pleasant".

  • Change in Olfactory-related Quality of Life from Baseline to 4 and 12 Weeks2 times: 4 weeks, 12 weeks

    The Modified Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS) consists of 17 negative statements (rated on a scale from 0 to 3; total score ranging from 0 to 51), with lower scores indicating better olfactory-related quality of life.

  • Change in Impact of Olfactory Loss from Baseline to 4 and 12 Weeks2 times: 4 weeks, 12 weeks

    The Impact of Olfactory Loss Visual Analog Scale (IOL-VAS) consists of 9 separate items assessing the impact of olfactory loss upon mood, food enjoyment, social interactions, safety, hygiene, sex, cooking, appetite, and weight changes, rated from 0 (no impact) to 10 (biggest impact possible).