An interventional study of Functional Electrical Stimulation Device in Obstructive Sleep Apnea (OSA) and Snoring, sponsored by Seoul National University Bundang Hospital. Recruiting at 1 site in South Korea. Open to participants aged 19 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-12.
Sponsored by Seoul National University Bundang Hospital · Not applicable, Interventional, and Basic science
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.
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.
2,240 studies on the registry are indexed under Sleep Apnea, Obstructive; 475 are open to participants now.
This study's planned enrollment of 28 is below the median of 52 across 1,472 interventional studies indexed under Sleep Apnea, Obstructive.
Browse Sleep Apnea, Obstructive studies →Seoul National University Bundang Hospital is the lead sponsor of 376 studies on the registry; 56 are open to participants now.
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Exclusion Criteria:
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An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Device: Functional Electrical Stimulation Device
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.
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.
Time frame: 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.
Time frame: 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.
Time frame: Before stimulation and immediately after completion of all frequency conditions during a single study visit (~1 hour)
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.
Time frame: During each stimulation frequency and immediately after completion of all frequency conditions during a single study visit (~1 hour)
Plan to share: No
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