LATE-BREAKING ABSTRACT: Randomised, sham-controlled, double-blind cross-over trial of transcutaneous electrical stimulation of the pharyngeal dilator muscles in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is characterised by a loss of neuromuscular tone of the upper airway dilator muscles while asleep. Positive airway pressure is a well-established long-term treatment, but patient compliance is limited. Alternative treatment options include the use of electrical current for hypoglossal nerve stimulation. This study investigated the effectiveness of transcutaneous electrical stimulation in patients with OSA. The current study was a randomised, sham-controlled and double blind cross-over trial using transcutaneous electrical stimulation of the upper airway dilator muscles in patients with OSA. Patients underwent a baseline polysomnography to assess the severity of OSA, followed by two randomly assigned nights of sham stimulation and active treatment. The primary outcome was the 4% oxygen desaturation index (ODI). 36 patients were recruited, the mean age was 50.8 (SD 11.2) years, 30 males, body-mass-index (BMI) mean 29.6 (SD 8.0) kg/m 2 , ODI median 25.7 (interquartile range, IQR 16.0-49.1) /hour. The ODI improved when comparing sham stimulation to active treatment (ODI median 26.9 (IQR 17.5-39.5) vs 19.5 (IQR 11.6-40.0) /hour; p=0.026) without affecting sleep architecture. Patients tolerated stimulation well, without adverse events. Responders (47.2%) were predominantly from the mild-moderate OSA category. In this subgroup, the oxygen desaturation index was reduced by 10.0 (95%CI 3.9-16.0) /hour (p Transcutaneous electrical stimulation of the pharyngeal dilators in patients with OSA can be delivered throughout the whole night. It is well tolerated and improves upper airway obstruction.