Neuromechanical interaction in human snoring and upper airway obstruction

The fact that snoring and obstructive apnea only occur during sleep means t hat effective neuromuscular functioning of the upper airway during sleep is vital for the maintenance of unimpeded breathing. Recent clinical studies in humans have obtained evidence demonstrating that upper airway neural rec eptors sense the negative pressure generated by inspiration and "trigger," with a certain delay, reflex muscle activation evidence demonstrating upper airway neural receptors sense the negative pressure rated by inspiration t o sustain the airway that otherwise collapse. These findings have enabled u s to pro a model in which the mechanics is coupled to the neuromuscular phy siology through the generation of reflex wall stiffening proportional to th e retarded fluid pressure. Preliminary results on this model exhibit three kinds of behavior typical of unimpeded breathing, snoring, and obstructive sleep apnea, respectively. We suggest that the increased latency of the ref lex muscle activation in sleep, together with the reduced strength of the r eflex, have important clinical consequences.