Olfactory ImpairmentPhase 2SCENT-OLNCT07689773
Study of Chemosensory Enhancement Through Neuromodulation Training (SCENT): Open Label
A Phase 2 study testing Trigeminal Nerve Stimulation-enhanced Smell Training in people with Olfactory Impairment, run by Medical University of South Carolina at 1 site in United States.
Trial summary
Smell dysfunction significantly impacts quality of life and safety, with limited effective treatments. This open-label study evaluates the preliminary efficacy of combining non-invasive trigeminal nerve stimulation (TNS) with standard smell training (ST) to improve olfactory function. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Olfactory Impairment
- What is being tested?
- Trigeminal Nerve Stimulation-enhanced Smell Training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Jul 2026to 30 Jun 2028
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age 18-80
- Self-reported or medically documented smell loss
- Treatment-seeking for their smell loss
- Naïve to TNS
- Able to comprehend English and provide informed consent
Who cannot join
- Medical Records not available to confirm eligibility
- Documented/Suspected head injury (e.g. sport, accident, blast exposure)
- Neurological disorder (e.g. epilepsy, neurodegenerative disorder)
- Serious mental illness (e.g. schizophrenia, bipolar disorder)
- Suicidal ideation within the last month
- Current (≤6 months) and/or heavy cigarette smokers (i.e. ≥ 10 pack-years)
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- Oral/nasal steroids or other intranasal medications
- Immunomodulatory medications
- Pregnant or trying to become pregnant
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Medical University of South Carolina
Charleston, South Carolina, 29425
Bernadette Cortese, Ph.D., 843-792-6922, corteseb@musc.edu
About this study
Smell dysfunction significantly impacts quality of life and safety, with limited effective treatments. This open-label study evaluates the preliminary efficacy of combining non-invasive trigeminal nerve stimulation (TNS) with standard smell training (ST) to improve olfactory function. Participants will complete 8 weeks of at-home treatment and attend three in-person visits for assessment. Improvements in smell, mood, sleep, and quality of life will be measured.
Read the detailed description
Smell dysfunction is a serious health issue associated with everyday dangers like the inability to correctly identify nearby hazards (e.g. burning, gas leaks, or spoiled food), psychosocial problems including social withdrawal and reduced quality and enjoyment of life, a myriad of psychiatric conditions, and a generally increased risk of mortality. Further escalating the gravity of olfactory dysfunction is mounting evidence of olfactory disturbance as prodromal to neurodegenerative disorder.
Smell/olfactory training (ST) has emerged as the first-line, and only (current) treatment for smell loss (SL). Classic ST requires twice daily practice of sniffing odorants over the course of 3 months to regenerate olfactory neurons, engage smell-related cognitive functions, and retrain the brain to smell. ST is promising as a stand-alone treatment for SL. However, limitations of ST include the burden of many months of daily practice that leads to sub-optimal compliance, dropout and modest effect sizes. Methods to accelerate and enhance the benefits of ST are needed.
The olfactory and intranasal trigeminal circuits are structurally and functionally coupled brain systems, both essential to smell function. In fact, there is widespread central overlap and convergence of these systems that is believed to underlie the strong mutual, inhibitory influence between the odor-processing functions of the olfactory pathway and the pungency-processing functions of the trigeminal pathway. Given the convergence and functional influence the circuits have on one another, it is likely that the trigeminal system can be leveraged to activate or enhance olfaction. As such, a method that directly engages the intranasal trigeminal system may be an effective strategy to improve olfactory function.
Trigeminal nerve stimulation (TNS) is a non-invasive, pain-free, method of neuromodulation that delivers low levels of electrical stimulation to the trigeminal circuit, having potential to enhance smell function through activation of the highly connected olfactory-intranasal trigeminal systems. The study investigator's previously published work demonstrated TNS-enhanced psychophysical detection of odorants in healthy adults. The TNS device is FDA 510(k)-cleared for the at-home treatment of pain and attention deficit hyperactivity disorder (ADHD); however, its use in this study is to enhance olfactory function.
For this study, the study investigators will conduct an at-home, open label trial of TNS-enhanced ST in adults. The primary objectives are to determine initial efficacy of TNS-enhanced ST at treating smell loss. Objectives will be achieved through the following aims:
Aim 1: Determine the effects of TNS-enhanced ST on olfactory deficits. The study investigators hypothesize that 8 weeks of TNS-enhanced ST will show significant improvement in psychophysical and subjective olfactory function at 8 weeks compared to baseline.
Aim 2: Determine if TNS-enhanced ST improve other symptoms associated with smell loss. The study investigators hypothesize that 8 weeks of TNS-enhanced ST will show significant improvement in mood, sleep and quality of life at 8 weeks compared to baseline.
- Conditions
- Olfactory Impairment
- Being tested
- Trigeminal Nerve Stimulation-enhanced Smell Training
- Keywords
- olfaction, smell loss, chronic rhinosinusitis, olfactory dysfunction, smell training, olfactory training, trigeminal nerve stimulation, sensory loss
- Medical subject headings
- Olfaction Disorders, Anosmia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Trigeminal Nerve Stimulation-enhanced Smell TrainingCombination product
TNS is a form of cranial nerve stimulation that uses a simple transcutaneous electrical nerve stimulation device, and adhesive electrodes that are attached to forehead to deliver low-level electrical current. Stimulating the trigeminal nerve activates the trigeminal afferent sensory pathway and central brain regions where the intranasal trigeminal and olfactory circuits converge. Smell Training requires 4 odors to be smelled individually for 10 sec each and record ratings.
| Study group | Role | What they receive |
|---|---|---|
| Open Label Trigeminal Nerve Stimulation-enhanced Smell Training (TNS-enhanced ST) | Experimental | TNS-enhanced ST will be administered at-home 5 days/week for 8 weeks. Participants will self-administer the first treatment of TNS-enhanced ST with the assistance and help of study staff. This includes attaching the gel pads to the forehead and turning the TNS system on for 30-min., training with different odorants and providing ratings on a website called REDCap, an easy-to-use, secure, internet-based data collection site. Receives: Combination Product: Trigeminal Nerve Stimulation-enhanced Smell Training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Psychophysical Olfactory Function from Baseline to 4 and 8 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.
Measured: 8 weeks
Change in Perceived Intensity of Odorants from Baseline to 4 and 8 Weeks
Perceived intensity on 100-mm visual analog scales with anchor points: 0="imperceptible" to 100="extremely intense".
Measured: 8 weeks
Change in Perceived Hedonics of Odorants from Baseline to 4 and 8 Weeks
Perceived hedonics on 100-mm visual analog scales with anchor points: 0="extremely unpleasant" to 100="extremely pleasant".
Measured: 8 weeks
Change in Olfactory-related Quality of Life from Baseline to 4 and 8 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.
Measured: 8 weeks
Change in Impact of Olfactory Loss from Baseline to 4 and 8 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).
Measured: 8 weeks
Secondary outcomes (4)
Change in Mood State from Baseline to 4 and 8 Weeks
The Profile of Mood States Short Form (POMS-SF) is a psychological rating scale used to assess transient, distinct mood states across six different dimensions including Tension or Anxiety, Anger or Hostility, Vigor or Activity, Fatigue or Inertia, Depression or Dejection, and Confusion or Bewilderment.
Measured: 8 weeks
Change in Sleep Quality from Baseline to 4 and 8 Weeks
The Pittsburgh Sleep Quality Index (PSQI) is a self-report questionnaire that assesses sleep quality over a 1-month time interval. The measure consists of 19 individual items, creating 7 components that produce one global score. Scores greater than 5 are indicative of a sleep disturbance.
Measured: 8 weeks
Change in Symptoms of Depression from Baseline to 4 and 8 Weeks
The Patient Health Questionnaire-9 (PHQ-9) is a self-administered 9-item questionnaire to screen for the presence and severity of depression. Items are rated on a 3pt scale ranging from 0="Not at all" to 3="Nearly every day". Total score ranges from 0-27 and is used to classify depression severity: 0-4=None/Minimal; 5-9=Mild; 10-14=Moderate; 15-19=Moderately Severe; 20-27=Severe.
Measured: 8 weeks
Change in Symptoms of Anxiety from Baseline to 4 and 8 Weeks
The Generalized Anxiety Disorder-7 (GAD-7) is a 7-item questionnaire to screen for presence and severity of anxiety disorder. Items are rated on a 3pt scale ranging from 0="Not at all" to 3="Nearly every day". Total score ranges from 0 to 21 and is used to classify anxiety severity: 0-4 (minimal anxiety), 5-9 (mild anxiety), 10-14 (moderate anxiety), 15-21 (severe anxiety).
Measured: 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Jul 2026
- Study start10 Jul 2026
- Primary completion30 Jun 2028 (estimated)
- Study completion30 Jun 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Olfactory ImpairmentStudies of the same condition, open and under way.
- More trials run by Medical University of South CarolinaThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Medical University of South Carolina
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Bernadette Cortese, Medical University of South Carolina
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07689773
- Sponsor's protocol ID
- Pro00151125
- Acronym
- SCENT-OL
- Status last verified
- Aug 2026
- First submitted
- 1 Jul 2026
- Last updated
- 12 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- Yes
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study of Chemosensory Enhancement Through Neuromodulation Training (SCENT): Open Label
- ClinicalTrials.gov ID
- NCT07689773
- Acronym / sponsor ID
- SCENT-OL / Pro00151125
- Conditions
- Olfactory Impairment
- Keywords
- olfaction, smell loss, chronic rhinosinusitis, olfactory dysfunction, smell training, olfactory training, trigeminal nerve stimulation, sensory loss
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- Medical University of South CarolinaUniversity, hospital or other
- Study start
- 10 Jul 2026 (actual)
- Primary completion
- 30 Jun 2028 (estimated)
- Study completion
- 30 Jun 2028 (estimated)
- First posted
- 8 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Smell dysfunction significantly impacts quality of life and safety, with limited effective treatments. This open-label study evaluates the preliminary efficacy of combining non-invasive trigeminal nerve stimulation (TNS) with standard smell training (ST) to improve olfactory function. Participants will complete 8 weeks of at-home treatment and attend three in-person visits for assessment. Improvements in smell, mood, sleep, and quality of life will be measured.
Detailed description
Smell dysfunction is a serious health issue associated with everyday dangers like the inability to correctly identify nearby hazards (e.g. burning, gas leaks, or spoiled food), psychosocial problems including social withdrawal and reduced quality and enjoyment of life, a myriad of psychiatric conditions, and a generally increased risk of mortality. Further escalating the gravity of olfactory dysfunction is mounting evidence of olfactory disturbance as prodromal to neurodegenerative disorder.
Smell/olfactory training (ST) has emerged as the first-line, and only (current) treatment for smell loss (SL). Classic ST requires twice daily practice of sniffing odorants over the course of 3 months to regenerate olfactory neurons, engage smell-related cognitive functions, and retrain the brain to smell. ST is promising as a stand-alone treatment for SL. However, limitations of ST include the burden of many months of daily practice that leads to sub-optimal compliance, dropout and modest effect sizes. Methods to accelerate and enhance the benefits of ST are needed.
The olfactory and intranasal trigeminal circuits are structurally and functionally coupled brain systems, both essential to smell function. In fact, there is widespread central overlap and convergence of these systems that is believed to underlie the strong mutual, inhibitory influence between the odor-processing functions of the olfactory pathway and the pungency-processing functions of the trigeminal pathway. Given the convergence and functional influence the circuits have on one another, it is likely that the trigeminal system can be leveraged to activate or enhance olfaction. As such, a method that directly engages the intranasal trigeminal system may be an effective strategy to improve olfactory function.
Trigeminal nerve stimulation (TNS) is a non-invasive, pain-free, method of neuromodulation that delivers low levels of electrical stimulation to the trigeminal circuit, having potential to enhance smell function through activation of the highly connected olfactory-intranasal trigeminal systems. The study investigator's previously published work demonstrated TNS-enhanced psychophysical detection of odorants in healthy adults. The TNS device is FDA 510(k)-cleared for the at-home treatment of pain and attention deficit hyperactivity disorder (ADHD); however, its use in this study is to enhance olfactory function.
For this study, the study investigators will conduct an at-home, open label trial of TNS-enhanced ST in adults. The primary objectives are to determine initial efficacy of TNS-enhanced ST at treating smell loss. Objectives will be achieved through the following aims:
Aim 1: Determine the effects of TNS-enhanced ST on olfactory deficits. The study investigators hypothesize that 8 weeks of TNS-enhanced ST will show significant improvement in psychophysical and subjective olfactory function at 8 weeks compared to baseline.
Aim 2: Determine if TNS-enhanced ST improve other symptoms associated with smell loss. The study investigators hypothesize that 8 weeks of TNS-enhanced ST will show significant improvement in mood, sleep and quality of life at 8 weeks compared to baseline.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Open Label Trigeminal Nerve Stimulation-enhanced Smell Training (TNS-enhanced ST) | Experimental | Combination Product: Trigeminal Nerve Stimulation-enhanced Smell TrainingTNS-enhanced ST will be administered at-home 5 days/week for 8 weeks. Participants will self-administer the first treatment of TNS-enhanced ST with the assistance and help of study staff. This includes attaching the gel pads to the forehead and turning the TNS system on for 30-min., training with different odorants and providing ratings on a website called REDCap, an easy-to-use, secure, internet-based data collection site. |
Who may qualify
- Ages
- 18 to 80 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Age 18-80
- Self-reported or medically documented smell loss
- Treatment-seeking for their smell loss
- Naïve to TNS
- Able to comprehend English and provide informed consent
Key exclusion criteria (9 listed)
- Medical Records not available to confirm eligibility
- Documented/Suspected head injury (e.g. sport, accident, blast exposure)
- Neurological disorder (e.g. epilepsy, neurodegenerative disorder)
- Serious mental illness (e.g. schizophrenia, bipolar disorder)
- Suicidal ideation within the last month
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Trigeminal Nerve Stimulation-enhanced Smell TrainingTNS is a form of cranial nerve stimulation that uses a simple transcutaneous electrical nerve stimulation device, and adhesive electrodes that are attached to forehead to deliver low-level electrical current. Stimulating the trigeminal nerve activates the trigeminal afferent sensory pathway and central brain regions where the intranasal trigeminal and olfactory circuits converge. Smell Training requires 4 odors to be smelled individually for 10 sec each and record ratings. | Combination product | Open Label Trigeminal Nerve Stimulation-enhanced Smell Training (TNS-enhanced ST) |
Primary outcome
Change in Psychophysical Olfactory Function from Baseline to 4 and 8 Weeks
Time frame: 8 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 8 Weeks
Time frame: 8 weeks
Perceived intensity on 100-mm visual analog scales with anchor points: 0="imperceptible" to 100="extremely intense".
Change in Perceived Hedonics of Odorants from Baseline to 4 and 8 Weeks
Time frame: 8 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 8 Weeks
Time frame: 8 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 8 Weeks
Time frame: 8 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).
4 secondary outcomes
Change in Mood State from Baseline to 4 and 8 Weeks
Time frame: 8 weeks
Change in Sleep Quality from Baseline to 4 and 8 Weeks
Time frame: 8 weeks
Change in Symptoms of Depression from Baseline to 4 and 8 Weeks
Time frame: 8 weeks
Change in Symptoms of Anxiety from Baseline to 4 and 8 Weeks
Time frame: 8 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Aug 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Trigeminal Nerve Stimulation-enhanced Smell Training in people with Olfactory Impairment, run by Medical University of South Carolina at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 9 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 12 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Bernadette Cortese, PhD (8437926922, corteseb@musc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in Psychophysical Olfactory Function from Baseline to 4 and 8 Weeks (time frame: 8 weeks). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Aug 2026.