Accuracy of the Sensory Test Using the Laryngopharyngeal Endoscopic Esthesiometer in Obstructive Sleep Apnea

INTRODUCTION: Obstructive sleep apnea-hypopnea syndrome (OSA) patients might have varying degrees of laryngopharyngeal mechanical hyposensitivity; however, these findings come from studies performed with methods having weak inter-rater reliability and accuracy evidence. The purpose of this study is to validate the measurement of laryngopharyngeal mechanosensitivity in patients with OSA using a recently developed laryngopharyngeal endoscopic esthesiometer and rangefinder (LPEER). The LPEER includes an air-pulse generator and an endoscopic laser rangefinder and works coupled to a conventional fiberoptic endoscope. This device generates air-pulses ranging from 0.04 mN to 16.5 mN in order to cover a wide range of laryngopharyngeal reflexes and sensory thresholds. Depending on the reflex or sensory threshold to be explored the LPEER is configured to deliver a sequence of 10 air-pulses of different intensity. METHODS: The study will be prospective, double blinded, and with a randomized and crossover assignment of the raters. Subjects will be recruited from patients with suspected OSA referred for baseline polysomnography to a sleep laboratory of a tertiary care university hospital. They will undergo a laryngopharyngeal sensory test using the LPEER, which includes measurement of the thresholds for the velopharyngeal, hypopharyngeal and aryepiglottic fold psychophysical sensitivity. Intra- and inter-rater reliability will be evaluated using the Bland-Altman's limits of agreement plot, the intraclass correlation coefficient, and the Pearson or Spearman correlation coefficient, depending on the distribution of the variables. Diagnostic accuracy will be evaluate plotting ROC-curves using as reference standard basal polysomnogram. The sensory threshold values for patients with mild, moderate, and severe OSA, will be determined and compared using ANOVA or Kruskal Wallis test, depending on the distribution of the variables.The discriminative capacity as well as correlations between laryngopharyngeal sensory thresholds and OSA severity indexes will be explored in subgroups of subjects with normal and abnormal sensation. The relationship between sensory thresholds and OSA severity indexes will be explored by linear equations as well as by second- and higher-order polynomial equations. The laryngopharyngeal endoscopic esthesiometer and rangefinder (LPEER), could be a new tool for the evaluation and monitoring of laryngopharyngeal sensory involvement in patients with OSA, which, if proved valid, could help to increase the knowledge about the pathophysiological mechanisms of this condition and potentially help finding new therapeutic interventions for OSA. ETHICS: This study will follow the Declaration of Helsinki principles and national legal regulations about research in human subjects. The protocol was approved by the Institutional Review Board of Fundacion Neumologica Colombiana and all recruited subjects will provided a signed informed consent. DISSEMINATION: The results will be disseminated through conference presentations and peer-reviewed publication.