Continuous Transcutaneous Submental Electrical Stimulation in Obstructive Sleep Apnea

Background The therapeutic value of transcutaneous electrical stimulation of the genioglossus muscle in patients with obstructive sleep apnea (OSA) to reduce sleep-disordered breathing is unclear. Methods Contraction of the genioglossus muscles during transcutaneous stimulation was investigated using ultrasonography in 11 healthy subjects (seven men, mean [SD] age 30 [6] years; BMI, 24.2 [3.5] kg/m2). Esophageal and gastric pressures were measured with balloon catheters, and transesophageal diaphragm electromyogram (EMGdi) was recorded during polysomnography in 11 patients with OSA (eight men, aged 51 [16] years; BMI, 42.0 [9.7] kg/m2) while transcutaneous electrical stimulation of the genioglossus was applied in non-rapid eye movement sleep (stage N2). Results Ultrasonography measurements showed a significant increase in tongue diameter during stimulation (sagittal: 10.0% [2.8%]; coronal: 9.4 % [3.7%]). The measurements were reproducible and repeatable. In patients with OSA, snoring decreased during stimulation (P < .001) and oxygenation improved (P = .001); the respiratory disturbance index (RDI) fell from 28.1 (26.3) to 10.2 (10.2) events per hour during stimulation (P = .002), returning to 26.6 (26.0) events per hour after stimulation was stopped. Transdiaphragmatic pressure swing decreased from 24.1 (13.5) cm H2O to 19.7 (7.1) cm H2O (P = .022), increasing to 24.2 (10.8) cm H2O afterward, and EMGdi fell from 23.8% max (12.6% max) to 15.7% max (6.4% max) (P < .001), rising to 22.6% max (10.4% max) post stimulation. Conclusions Continuous transcutaneous electrical stimulation of the genioglossus contracts the genioglossus muscle and reduces ventilatory load and neural respiratory drive in patients with OSA. The therapeutic value of transcutaneous electrical stimulation of the genioglossus muscle in patients with obstructive sleep apnea (OSA) to reduce sleep-disordered breathing is unclear. Contraction of the genioglossus muscles during transcutaneous stimulation was investigated using ultrasonography in 11 healthy subjects (seven men, mean [SD] age 30 [6] years; BMI, 24.2 [3.5] kg/m2). Esophageal and gastric pressures were measured with balloon catheters, and transesophageal diaphragm electromyogram (EMGdi) was recorded during polysomnography in 11 patients with OSA (eight men, aged 51 [16] years; BMI, 42.0 [9.7] kg/m2) while transcutaneous electrical stimulation of the genioglossus was applied in non-rapid eye movement sleep (stage N2). Ultrasonography measurements showed a significant increase in tongue diameter during stimulation (sagittal: 10.0% [2.8%]; coronal: 9.4 % [3.7%]). The measurements were reproducible and repeatable. In patients with OSA, snoring decreased during stimulation (P < .001) and oxygenation improved (P = .001); the respiratory disturbance index (RDI) fell from 28.1 (26.3) to 10.2 (10.2) events per hour during stimulation (P = .002), returning to 26.6 (26.0) events per hour after stimulation was stopped. Transdiaphragmatic pressure swing decreased from 24.1 (13.5) cm H2O to 19.7 (7.1) cm H2O (P = .022), increasing to 24.2 (10.8) cm H2O afterward, and EMGdi fell from 23.8% max (12.6% max) to 15.7% max (6.4% max) (P < .001), rising to 22.6% max (10.4% max) post stimulation. Continuous transcutaneous electrical stimulation of the genioglossus contracts the genioglossus muscle and reduces ventilatory load and neural respiratory drive in patients with OSA.