Effects of Frequency Adjustment in Functional Electrical Stimulation on Genioglossus Muscle Activity

NCT07466888 | Recruiting DMC

• 1 other identifier: B-2506-978-001
• Study Type: interventional
• Target: 28
• Locations: 1 country
• Sites: 1

Brief 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. 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.

Conditions

Obstructive Sleep Apnea (OSA); Snoring

Keywords

Obstructive Sleep Apnea (OSA); Snoring; FES

Outcome Measures

Primary Outcomes (3)

• 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.

  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.

  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.

  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

  During each stimulation frequency and immediately after completion of all frequency conditions during a single study visit (~1 hour)

Study Arms (1)

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.

Device: Functional Electrical Stimulation Device

Interventions

Functional Electrical Stimulation Device 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.

Multi-frequency Functional Electrical Stimulation

Eligibility Criteria

• Age: 19 Years+
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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)
• 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

Sponsors & Collaborators

• Seoul National University Bundang Hospital: lead
• National Research Foundation of Korea: collaborator

Study Sites (1)

Seoul National University Bundang Hospital

Gyeonggi-do, Seongnam-si, 463-707, South Korea

RECRUITING

MeSH Terms

Conditions

Sleep Apnea, Obstructive; Snoring

Condition Hierarchy (Ancestors)

Sleep Apnea Syndromes; Apnea; Respiration Disorders; Respiratory Tract Diseases; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Wake Disorders; Nervous System Diseases; Respiratory Sounds; Signs and Symptoms, Respiratory; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Officials

• Jee Hyun Suh, M.D., Ph.D.

  Seoul National University Bundang Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Juseok Ryu, M.D., Ph.D.

CONTACT

+82-31-787-7739; jseok337@snu.ac.kr

Hyunjin KIM

CONTACT

+82-10-9974-7152

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Masking Details: This is an open-label study. Both participants and investigators are aware that functional electrical stimulation is administered during the study session. No sham stimulation or separate comparison group is included.
• Purpose: BASIC SCIENCE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: 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.

Study Record Dates

• First Submitted: February 24, 2026
• First Posted: March 12, 2026
• Study Start: January 6, 2026
• Primary Completion: March 1, 2026
• Study Completion: April 1, 2026
• Last Updated: March 12, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

KR (1)