Determining the Relationship Between Hyoid Bone Kinematics and Airway Protection in Swallowing

Research remains equivocal regarding the links between hyoid movement and penetration–aspiration. The aims of this study were (a) to explore associations between hyoid parameters, laryngeal vestibule closure (LVC) parameters, and penetration–aspiration on thin liquids; and (b) to determine which of these parameters are the strongest predictors of penetration–aspiration.This study involved retrospective analysis of an existing videofluoroscopy data set, collected in 305 participants (152 males) with noncongenital/nonsurgical/non-oncological risk for dysphagia. We extracted data for six thin liquid swallows per participant, and obtained measures of hyoid movement (peak position, speed) and LVC (complete/incomplete, timing, duration). Resulting values were coded as typical/atypical relative to healthy reference data. Relationships were explored using chi-square tests and odds ratios (a) for the entire data set and (b) for the subset of data with complete LVC. Hierarchical logistic regression models determined the strongest predictors of penetration–aspiration.Significant associations were found between penetration–aspiration and incomplete LVC, prolonged time-to-most-complete-LVC, short LVC duration, reduced anterior hyoid peak position, and reduced hyoid speed. Hyoid measures were also significantly associated with LVC parameters. In the first regression model, incomplete LVC and prolonged time-to-most-complete-LVC were the only significant predictors of penetration–aspiration. For cases with complete LVC, the only significant predictor was prolonged time-to-most-complete-LVC.Although reduced anterior hyoid peak position and speed are associated with penetration–aspiration on thin liquids, these measures do not independently account for penetration–aspiration when considered in conjunction with measures of LVC. When identifying mechanisms explaining penetration–aspiration, clinicians should focus on LVC (complete/incomplete) and timeliness of LVC.