Laryngeal Hyposensitivity in Obstructive Sleep Apnea

Introduction: Impaired laryngopharyngeal sensation has been implicated in obstructive sleep apnea (OSA) and may play an important pathophysiological role. We evaluated sensory function in OSA by examining the laryngeal adductor reflex (LAR) response rate and temporal profile to tactile stimulation.

Methods: Laryngeal sensation testing was performed in awake adults with and without diagnosed OSA by stimulating the medial aryepiglottic fold or arytenoid using 30-mm 5-0 and 4-0 nylon Cheung-Bearelly monofilaments. Video analysis by two independent reviewers evaluated for the presence of the LAR in response to satisfactory stimuli and LAR latency to vocal fold adduction.

Results: Twenty-six OSA and 12 control subjects were tested with 270 satisfactory stimuli. The mean full LAR response rate to 4-0 stimulation was 38.3% in OSA vs 86.9% in control subjects (p <0.001) and to 5-0 stimulation was 27% in OSA vs 63.9% in control subjects (p <0.001). The mean LAR latency to vocal fold closure in OSA was 123.7 ms (SD 35.8) vs 156.4 ms (SD 44.3) in control (p = 0.04) subjects. OSA LAR latency was positively correlated with the apnea-hypopnea index (r = 0.30; p = 0.008).

Conclusion: The OSA group exhibited reduced LAR response rates and shortened LAR latency, where latency was correlated with disease severity. Laryngeal hyposensitivity was affirmed and changes to LAR sensorimotor temporal dynamics were revealed. These pathophysiological alterations to the LAR may be accounted for by decreased somatosensory receptor sensitivity, increased sympathetic tone, and reorganized brain stem function in OSA.

Level of evidence: 3 Laryngoscope, 134:3856-3861, 2024.