First results on daytime submandibular electrostimulation of suprahyoidal muscles to prevent night-time hypopharyngeal collapse in obstructive sleep apnea syndrome

Daytime submandibular electrostimulation (dSE) of suprahyoidal muscles was applied to prevent sleep-associated collapse of the tongue into the hypopharyngeal airway. By placing the stimulatory electrodes intra- and extraorally, recruitment of stimulated muscle fibers at low current densities was improved. The significant impact of electrostimulation on suprahyoidal muscle force was initially demonstrated in healthy controls as compared to placebo-treated volunteers. The morphology of suprahyoidal muscles was not affected by this treatment. A patient with obstructive sleep apnea syndrome initially presented with a respiratory disturbance index (RDI) of 13.2, an oxygen desaturation index of 23 and a minimal oxygen saturation of 75%. After two weeks of placebo treatment (TENS-stimulation), respiratory parameters remained unchanged. Two weeks of dSE treatment, however, improved the RDI to 3.9, the oxygen desaturation index from 23 to 2.8 and the minimal oxygen saturation from 75% to 88%. 3D-sonography showed considerable hypertrophy of the stimulated muscles. These results indicate that dSE may prevent episodes of apnea induced by sleep-associated hypopharyngeal collapse of the tongue.