Obstructive Sleep Apnea (OSA)NCT07466888
Effects of Frequency Adjustment in Functional Electrical Stimulation on Genioglossus Muscle Activity
A study testing Functional Electrical Stimulation Device in people with Obstructive Sleep Apnea (OSA) and Snoring, run by Seoul National University Bundang Hospital at 1 site in South Korea.
Trial summary
This single-group interventional study investigates the safety and physiologic effects of functional electrical stimulation (FES) applied to the tongue and submental muscles in adults at high risk for sleep apnea. Read more about this study
- Who is it for?
- Ages 19 years and olderHealthy volunteers can take part
- Conditions the study is for
- Obstructive Sleep Apnea (OSA), Snoring
- What is being tested?
- Functional Electrical Stimulation Device
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 28 participants
- Where
- 1 siteSouth Korea
- Study dates
- 6 Jan 2026to Apr 2026
- Phase
- Interventional
- 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 19 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adults aged 19 years or older
- STOP questionnaire score ≥ 2
- Able to read and write in Korean
- Voluntarily provides written informed consent to participate in the study
Who cannot join
- Refusal to undergo study procedures or failure to provide informed consent
- Cognitive impairment or psychiatric disorders that interfere with the ability to follow study instructions
- Pregnant or breastfeeding women
- Known allergy or hypersensitivity to electrical stimulation pads or related materials (e.g., silicone, polypropylene, polyethylene)
- Skin conditions preventing application of electrical stimulation (e.g., hypersensitive skin)
- Medical conditions considered unsuitable for participation by the investigator (e.g., epilepsy, malignant tumor, high fever, diabetes mellitus, use of anticoagulants, phlebitis, thrombophlebitis, hemophilia)
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- Infectious disease or local conditions at the stimulation site (e.g., inflammation, wounds, abscess, edema)
- Known cardiac disease or presence of a cardiac pacemaker or implanted electrical stimulation device
- History of surgery involving the submental area or upper airway region
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Hyunjin KIM contact
South Korea1 site, 1 recruiting
- Recruiting
Seoul National University Bundang Hospital
Gyeonggi-do, Seongnam-si, 463-707
Hyunjin KIM, +82-10-9974-7152, RQ300@snubh.org
About this study
This single-group interventional study investigates the safety and physiologic effects of functional electrical stimulation (FES) applied to the tongue and submental muscles in adults at high risk for sleep apnea. Participants will receive five stimulation frequencies (15, 25, 35, 45, and 75 Hz) in randomized order during a single visit. Ultrasound and tongue pressure (IOPI) measurements, as well as subjective assessments of discomfort and perceived effects, will be conducted before, during, and after stimulation. The primary objective is to evaluate changes in muscle thickness, length, and tongue strength across different stimulation frequencies. Secondary objectives include assessing participant discomfort, safety, and subjective treatment effects.
Read the detailed description
Reduced tone and weakness of the genioglossus muscle are critical factors in the pathophysiology of obstructive sleep apnea (OSA). In addition to the genioglossus, other upper airway-related muscles, including the thyrohyoid and additional infrahyoid muscles, contribute to airway stability. These muscles differ in anatomical depth from the skin surface and in muscle thickness, which necessitates differentiated electrical stimulation approaches to ensure selective activation and safety.This clinical trial is designed to evaluate the safety and efficacy of functional electrical stimulation (FES) applied to the genioglossus muscle with modulation of stimulation frequency. The study aims to determine whether frequency adjustment influences muscle morphology and functional outcomes.The primary objective is to assess frequency-dependent changes in muscle length and thickness using ultrasonography, as well as differences in tongue strength measured by the Iowa Oral Performance Instrument (IOPI) before and after electrical stimulation.The secondary objective is to evaluate discomfort, safety, and subjective treatment effects through questionnaires administered before and after the electrical stimulation intervention.
- Conditions
- Obstructive Sleep Apnea (OSA), Snoring
- Being tested
- Functional Electrical Stimulation Device
- Keywords
- Obstructive Sleep Apnea (OSA), Snoring, FES
- Medical subject headings
- Sleep Apnea, Obstructive, Snoring
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Functional Electrical Stimulation DeviceDevice
A functional electrical stimulation device is applied to the submental region using surface adhesive electrodes. Stimulation is delivered at five different frequencies (15, 25, 35, 45, and 75 Hz) in randomized sequence during a single study visit. Each frequency is administered within the same session to evaluate immediate physiologic responses of the tongue muscles. Participants are blinded to the stimulation frequency applied during each condition.
| Study group | Role | What they receive |
|---|---|---|
| Multi-frequency Functional Electrical Stimulation | Experimental | All participants receive a single-session multi-frequency functional electrical stimulation protocol (15-75 Hz) applied in randomized order. Ultrasound and tongue pressure (IOPI) measurements are performed before and after stimulation, while subjective assessments of discomfort and perceived effects are collected during each stimulation frequency. Participants are blinded to stimulation frequency. Receives: Device: Functional Electrical Stimulation Device |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in genioglossus muscle thickness measured by ultrasonography
The thickness of the genioglossus muscle is measured using ultrasonography before and immediately after electrical stimulation at each frequency (15, 25, 35, 45, and 75 Hz) during a single study visit.
Measured: Before and immediately after stimulation at each frequency during a single study visit (~1 hour)
Change in genioglossus muscle length measured by ultrasonography
The length of the genioglossus muscle is measured using ultrasonography before and immediately after electrical stimulation at each frequency (15, 25, 35, 45, and 75 Hz) during a single study visit.
Measured: Before and immediately after stimulation at each frequency during a single study visit (~1 hour)
Change in tongue strength measured by the Iowa Oral Performance Instrument (IOPI)
Tongue strength is measured using the Iowa Oral Performance Instrument (IOPI) in kilopascals (kPa) before electrical stimulation and immediately after completion of all frequency conditions during a single study visit (~1 hour). IOPI scores range from 0 kPa (no measurable pressure) to approximately 70 kPa (maximum tongue strength), with higher scores indicating greater tongue strength.
Measured: Before stimulation and immediately after completion of all frequency conditions during a single study visit (~1 hour)
Secondary outcomes (1)
Participant-reported discomfort associated with electrical stimulation
Participant discomfort is assessed using a 1-5 Likert scale questionnaire during each stimulation frequency and immediately after completion of all frequency conditions during the study visit (~1 hour). Scale interpretation: 1 = very uncomfortable, 2 = uncomfortable, 3 = neutral, 4 = comfortable, 5 = very comfortable. Higher scores indicate greater comfort.
Measured: During each stimulation frequency and immediately after completion of all frequency conditions during a single study visit (~1 hour)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Mar 2026
- Study start6 Jan 2026
- Primary completionMar 2026 (estimated)
- Study completionApr 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep Apnea (OSA)Studies of the same condition, open and under way.
- More trials run by Seoul National University Bundang HospitalThe 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 N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- This is a single-group interventional study in which all participants undergo a multi-frequency functional electrical stimulation protocol during a single study visit. The protocol includes five stimulation frequencies (15, 25, 35, 45, and 75 Hz) applied in randomized order within the same session. Outcomes are assessed before, during, and immediately after stimulation to evaluate within-subject physiologic responses.
- Masking
- None (open label)
- Enrolment
- 28 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Seoul National University Bundang Hospital
- Sponsor type
- University, hospital or other
- Collaborators
- National Research Foundation of Korea
- Responsible party
- Principal investigator, JeeHyun Suh, Seoul National University Bundang Hospital
- Investigators
- Jee Hyun Suh, M.D., Ph.D., Principal investigator, Seoul National University Bundang Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07466888
- Sponsor's protocol ID
- B-2506-978-001
- Status last verified
- Mar 2026
- First submitted
- 24 Feb 2026
- Last updated
- 12 Mar 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 12 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Frequency Adjustment in Functional Electrical Stimulation on Genioglossus Muscle Activity
- ClinicalTrials.gov ID
- NCT07466888
- Acronym / sponsor ID
- B-2506-978-001
- Conditions
- Obstructive Sleep Apnea (OSA), Snoring
- Keywords
- Obstructive Sleep Apnea (OSA), Snoring, FES
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 28 participants (estimated)
- Lead sponsor
- Seoul National University Bundang HospitalUniversity, hospital or other
- Collaborators
- National Research Foundation of Korea
- Study start
- 6 Jan 2026 (actual)
- Primary completion
- Mar 2026 (estimated)
- Study completion
- Apr 2026 (estimated)
- First posted
- 12 Mar 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.
This single-group interventional study investigates the safety and physiologic effects of functional electrical stimulation (FES) applied to the tongue and submental muscles in adults at high risk for sleep apnea. Participants will receive five stimulation frequencies (15, 25, 35, 45, and 75 Hz) in randomized order during a single visit. Ultrasound and tongue pressure (IOPI) measurements, as well as subjective assessments of discomfort and perceived effects, will be conducted before, during, and after stimulation. The primary objective is to evaluate changes in muscle thickness, length, and tongue strength across different stimulation frequencies. Secondary objectives include assessing participant discomfort, safety, and subjective treatment effects.
Detailed description
Reduced tone and weakness of the genioglossus muscle are critical factors in the pathophysiology of obstructive sleep apnea (OSA). In addition to the genioglossus, other upper airway-related muscles, including the thyrohyoid and additional infrahyoid muscles, contribute to airway stability. These muscles differ in anatomical depth from the skin surface and in muscle thickness, which necessitates differentiated electrical stimulation approaches to ensure selective activation and safety.This clinical trial is designed to evaluate the safety and efficacy of functional electrical stimulation (FES) applied to the genioglossus muscle with modulation of stimulation frequency. The study aims to determine whether frequency adjustment influences muscle morphology and functional outcomes.The primary objective is to assess frequency-dependent changes in muscle length and thickness using ultrasonography, as well as differences in tongue strength measured by the Iowa Oral Performance Instrument (IOPI) before and after electrical stimulation.The secondary objective is to evaluate discomfort, safety, and subjective treatment effects through questionnaires administered before and after the electrical stimulation intervention.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- This is a single-group interventional study in which all participants undergo a multi-frequency functional electrical stimulation protocol during a single study visit. The protocol includes five stimulation frequencies (15, 25, 35, 45, and 75 Hz) applied in randomized order within the same session. Outcomes are assessed before, during, and immediately after stimulation to evaluate within-subject physiologic responses.
| Arm | Type | Receives |
|---|---|---|
| Multi-frequency Functional Electrical Stimulation | Experimental | Device: Functional Electrical Stimulation DeviceAll participants receive a single-session multi-frequency functional electrical stimulation protocol (15-75 Hz) applied in randomized order. Ultrasound and tongue pressure (IOPI) measurements are performed before and after stimulation, while subjective assessments of discomfort and perceived effects are collected during each stimulation frequency. Participants are blinded to stimulation frequency. |
Who may qualify
- Ages
- 19 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Adults aged 19 years or older
- STOP questionnaire score ≥ 2
- Able to read and write in Korean
- Voluntarily provides written informed consent to participate in the study
Key exclusion criteria (9 listed)
- Refusal to undergo study procedures or failure to provide informed consent
- Cognitive impairment or psychiatric disorders that interfere with the ability to follow study instructions
- Pregnant or breastfeeding women
- Known allergy or hypersensitivity to electrical stimulation pads or related materials (e.g., silicone, polypropylene, polyethylene)
- Skin conditions preventing application of electrical stimulation (e.g., hypersensitive skin)
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 |
|---|---|---|
| Functional Electrical Stimulation DeviceA functional electrical stimulation device is applied to the submental region using surface adhesive electrodes. Stimulation is delivered at five different frequencies (15, 25, 35, 45, and 75 Hz) in randomized sequence during a single study visit. Each frequency is administered within the same session to evaluate immediate physiologic responses of the tongue muscles. Participants are blinded to the stimulation frequency applied during each condition. | Device | Multi-frequency Functional Electrical Stimulation |
Primary outcome
Change in genioglossus muscle thickness measured by ultrasonography
Time frame: Before and immediately after stimulation at each frequency during a single study visit (~1 hour)
The thickness of the genioglossus muscle is measured using ultrasonography before and immediately after electrical stimulation at each frequency (15, 25, 35, 45, and 75 Hz) during a single study visit.
Change in genioglossus muscle length measured by ultrasonography
Time frame: Before and immediately after stimulation at each frequency during a single study visit (~1 hour)
The length of the genioglossus muscle is measured using ultrasonography before and immediately after electrical stimulation at each frequency (15, 25, 35, 45, and 75 Hz) during a single study visit.
Change in tongue strength measured by the Iowa Oral Performance Instrument (IOPI)
Time frame: Before stimulation and immediately after completion of all frequency conditions during a single study visit (~1 hour)
Tongue strength is measured using the Iowa Oral Performance Instrument (IOPI) in kilopascals (kPa) before electrical stimulation and immediately after completion of all frequency conditions during a single study visit (~1 hour). IOPI scores range from 0 kPa (no measurable pressure) to approximately 70 kPa (maximum tongue strength), with higher scores indicating greater tongue strength.
1 secondary outcome
Participant-reported discomfort associated with electrical stimulation
Time frame: During each stimulation frequency and immediately after completion of all frequency conditions during a single study visit (~1 hour)
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 Mar 2026.
- Individual participant dataSharing planned: No
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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.
Hyunjin KIM contact
Jee Hyun Suh, M.D., Ph.D. principal investigator
Seoul National University Bundang Hospital
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Functional Electrical Stimulation Device in people with Obstructive Sleep Apnea (OSA) and Snoring, run by Seoul National University Bundang Hospital at 1 site in South Korea.
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 4 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 Mar 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 South Korea. 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.
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 Juseok Ryu, M.D., Ph.D. (+82-31-787-7739, jseok337@snu.ac.kr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in genioglossus muscle thickness measured by ultrasonography (time frame: Before and immediately after stimulation at each frequency during a single study visit (~1 hour)). The study lists 3 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 Mar 2026.