Closed-loop Stimulations of Hypoglossal Nerve Using Its Spontaneous Activity as the Feedback Signal

Electrical recruitment of the upper airway (UAW) muscles has been attempted as a treatment method for Obstructive Sleep Apnea (OSA) [l-61. Hypoglossal nerve (HG) and genioglossus muscle (GG) stimulations have given successful results in OSA patients [3-61. A reliable method for detection of obstructions is needed to trigger the stimulations in phase with respiration during obstructive breaths before this technique can be used clinically. In this paper, we investigate the possibility of closed-loop HG nerve stimulations using its spontaneous activity for detection of obstructions in a dog model. The activity of the HG nerve is recorded with chronically implanted nerve cuff electrodes in sleeping dogs while a force is being applied onto the submental region to collapse the airways. The increase in the phasic HG activity as a response to the submental force is used to trigger the stimulations. Closed-loop stimulations are shown to relieve the UAWs from the collapsing effect of the submental force.