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