A neural prosthesis for obstructive sleep apnea

Electrical stimulation of the hypoglossal (XII) nerve has been demonstrated as an effective approach to treating obstructive sleep apnea (OSA). The physiological effects of conventional modes of stimulation (i.e., genioglossus activation or whole XII nerve stimulation), however, have yielded inconsistent and only partial alleviations of hypoapneic or apneic events. While selective stimulation of the multi-fasciculated XII nerve offers many stimulus options, it is not clear how they will functionally affect the upper airway (UAW). To study these effects, animal experiments in four beagles were performed to investigate changes in critical pressure (P,fit), during inspiration. For simulated inspiration, only whole XII nerve stimulation (-0.9 0.4 cmH(2)O) and co-activation of the GG + HG/SG muscles (-1.18 +/- 0.6 cmH(2)O) produced significant (p < 0.05) improvements in UAW stability (i.e., lowered P-crit), compared to baseline (452 +/- 0.32 cmH(2)O). The results of this study suggest that a multi-contact nerve electrode can achieve both UAW dilation and patency, comparable to that obtained with non-selective stimulation by selectively activating the various branches of the XII nerve.