The myopathic endotype of obstructive sleep apnea

There is a wide range of therapeutic options available for the treatment of obstructive sleep apnea, which is due to the heterogeneic nature of the condition.  Indeed, obstructive sleep apnea can present differently in both children and adults. However, the common goal of various therapies is to achieve upper airway homeostasis and avoid upper airway collapse during sleep, including its sequela of apnea, hypopnea, arousals, etc. It is now taught that obstructive sleep apnea endotyping refers to the underlying pathophysiologic mechanisms that precipitate upper airway collapse. These four endotypic traits are commonly classified as: Pharyngeal collapsibility (Pcrit); Upper airway dilator muscle responsiveness; Respiratory arousal threshold, and Loop gain.  Thus, upper airway collapsibility (Pcrit) may be related to structural concerns (such as craniofacial architecture), which might require either non-surgical or surgical intervention; however, confounding metabolic factors, such as obesity, might also need to be taken into consideration. On the other hand, poor upper airway muscle responsiveness may be present as myopathic conditions (either syndromic or non-syndromic). Here, patient-directed interventions, such as oral myofunctional therapy, come to the forefront although some novel medical devices and apps have recently become available. Other unfavorable upper airway behavior, such as loop gain, represents ventilatory control instability, while respiratory effort related arousals indicate a neurologic basis for sleep fragmentation. Thus, the mechanisms by which diverse treatment approaches address the various endotypes of obstructive sleep apnea require further discussion. Therefore, the aim of this presentation is to clarify therapeutic mechanisms available for the management of obstructive sleep apnea because a substantial proportion of patients do not respond to, or adhere to, anatomically directed therapy, and there is a shift toward characterizing endotypic traits to enable precision, mechanism-targeted management. Specifically, this presentation will note how the mechanism(s) by which oral myofunctional therapies successfully ameliorate the severity of OSA require positioning in the context of neuromuscular control, functional response and dynamic upper airway behavior that deploys an integrated approach to upper airway homeostasis.