Obstructive sleep apnea (OSA) is a highly prevalent disease resulting from dynamic upper airway collapse during sleep. Continuous positive airway pressure (CPAP) is highly efficacious but high rates of non-adherence to CPAP leaves large number of OSA patients at risk for cardiometabolic sequelae. Inspire™ is an FDA-approved hypoglossal nerve stimulation device (HGNS) used in select patients with OSA who are intolerant of CPAP. The device consists of an implanted impulse generator with a stimulating cuff lead around the distal hypoglossal nerve. Despite these stringent selection criteria, up to one-third of patients implanted have inadequate responses to HGNS and remain at risk for complications from untreated OSA. The current proposal builds on routine clinical care to characterize upper airway biomechanics and determine predictors of clinical responses to HGNS therapy. Drug induced sleep endoscopy (DISE) is a prerequisite for HGNS treatment and represents an ideal opportunity to rapidly characterize upper airway dynamics under controlled, standardized conditions. The amount of nasal pressure required to relieve airway obstruction (minimal therapeutic pressure) is a significant predictor of successful treatment of OSA with HGNS. As a result, CPAP titration (measuring pharyngeal collapse patterns at varying nasal pressures) has become an integral part of DISE to select parties for HGNS at multiple institutions. Nevertheless, changes in upper airway collapsibility in response HGNS may differ significantly between patients. This stud will examine if changes in upper airway patency with direct genioglossus muscle stimulation at the time of DISE predicts successful treatment with HGNS as defined by a 50% reduction on apnea-hypopnea index (AHI) and an on-treatment AHI \<20.