Laryngeal and velopharyngeal sensory impairment in obstructive sleep apnea

Study Objective: To determine whether mucosal sensory dysfunction is present at multiple upper-airway sites in patients with obstructive sleep apnea (OSA). Design: Physiologic testing of consecutive patients with OSA and nonsnoring controls. Setting: University hospital sleep center. Participants: Thirty-nine subjects with OSA and 17 controls. Interventions: Endoscopic testing was used to determine sensory detection thresholds for air-pressure pulses delivered to the oropharynx, velopharynx, hypopharynx, and larynx (aryepiglottic eminence). The air-pulse stimulus intensity required to elicit the protective laryngeal adductor reflex was also determined. Measurements and Results: There was a significant impairment in sensory detection threshold for OSA versus control subjects in the oropharynx, as previously described by ourselves using other techniques, as well as at the velopharynx (median 11 mm Hg [confidence interval 9-11] for subjects with OSA vs 8 mm Hg [confidence interval 4-11] for controls, P = .03) and, at the larynx, 4 mm Hg [confidence interval 2-9] for subjects with OSA vs 2 mm Hg [confidence interval 2-3] for controls, P < .001). The threshold stimulus intensity for the laryngeal adductor reflex was also significantly higher for OSA subjects. For OSA patients with abnormal laryngeal sensation (61% of OSA subjects), there were significant correlations between laryngeal sensory values and measures of apnea severity, including apnea-hypopnea index (r= 0.82, P < .001) and nadir SaO(2) (r= -0.48, P < .05). Conclusion: Mucosal sensory function is impaired at multiple upper-airway sites in OSA.