RESUMEN
STUDY OBJECTIVES: There are only a few reports on voluntary swallowing during sleep; therefore, this study aimed to propose a method for observing voluntary swallowing during sleep using polysomnography. The frequency of voluntary swallowing during sleep and the factors related to swallowing and aspiration during sleep were investigated. METHODS: Polysomnography records of 20 control subjects and 60 patients with obstructive sleep apnea (OSA) (mild, moderate, and severe groups; n = 20 each) were collected. Simultaneous increases in the electromyographic potentials of the submental and masseter muscles, termed coactivation, and declining oronasal airflow (SA) were extracted as "swallowing." The cough reflex that occurred during sleep was extracted as "aspiration." The frequency of swallowing events was compared among the different OSA severity groups. Subsequently, a multivariate regression analysis was performed. RESULTS: The average frequency of coactivation with SA in control subjects was 4.1 events/h and that without SA was 1.7 events/h. These frequencies increased with the severity of OSA during non-REM sleep. The distance of the hyoid to the Frankfurt plane was associated with the frequency of coactivation with (ß = 0.298, p = 0.017) as well as without SA (ß = 0.271, p = 0.038). The frequency of coactivation without SA was associated with aspiration (B = 0.192, p = 0.042). CONCLUSIONS: Our data provide new insights into the relationship between swallowing and aspiration during sleep. We found that the longer the distance from the hyoid bone to the Frankfurt plane, the higher the coactivation without SA, which could lead to aspiration during sleep. CLINICAL TRIALS: Retrospective observational study of swallowing during sleep in obstructive sleep apnea patients using polysomnography, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000050460, UMIN000044187.
Asunto(s)
Deglución , Apnea Obstructiva del Sueño , Deglución/fisiología , Humanos , Hueso Hioides , Polisomnografía , Sueño , Apnea Obstructiva del Sueño/complicacionesRESUMEN
Study Objectives: Animal studies suggest a pivotal role of the hyoid bone in obstructive sleep apnea (OSA). We aimed to explore the role of the hyoid bone in humans by testing the hypotheses that muscle paralysis and lung volume (LV) changes displace the hyoid bone position particularly in people with obesity and/or OSA. Methods: Fifty patients undergoing general anesthesia participated in this study (20 participants with nonobese, non-OSA; 8 people with nonobese OSA; and 22 people with obese OSA). Three lateral neck radiographs to assess the hyoid position (primary variable) and craniofacial structures were taken during wakefulness, complete muscle paralysis under general anesthesia, and LV increase under general anesthesia. LV was increased by negative extrathoracic pressure application and LV changes were measured with a spirometer. Analysis of covariance was used to identify statistical significance. Results: Muscle paralysis under general anesthesia significantly displaced the hyoid bone posteriorly (95% CI: 1.7 to 4.6, 1.5 to 5.2, and 1.1 to 4.0 mm in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively), and this was more prominent in people with central obesity. LV increase significantly displaced the hyoid bone caudally in all groups (95% CI: 0.2 to 0.7, 0.02 to 0.6, and 0.2 to 0.6 mm/0.1 liter LV increase in nonobese non-OSA, nonobese OSA, and obese OSA groups, respectively). Waist-hip ratio was directly associated with the caudal displacement during LV increase. Conclusions: The hyoid bone plays an important role in the pathophysiology of pharyngeal airway obstruction due to muscle paralysis and LV reduction, particularly in people with obesity. Clinical Trial: UMIN Clinical Trial Registry, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=cR000022635&language=E, UMIN000019578.