Hyoid movement and laryngeal penetration during sequential swallowing.

This study examined hyoid movement during sequential swallowing and evaluated the relationship among trajectory patterns, swallowing types based on laryngeal movement and laryngeal penetration. Twelve healthy adults underwent videofluorography during sequential swallowing. Each swallow was classified into two types: opened laryngeal vestibule after swallow (i-Segmental type) and closed laryngeal vestibule after swallow (i-Continuous type). Each participant's swallowing type was classified by the same method. We analyzed two-dimensional movements of the hyoid, and the trajectories were classified into three patterns: hyoid moved in the anterosuperior direction after the onset of swallow (pattern L); hyoid moved in the anterosuperior direction after the onset of swallow, beyond the mandibular plane (pattern X); and the hyoid was above the mandibular plane at the onset of swallow, and then it moved in the inferior direction (pattern U). Two-way ANOVA revealed that there was a significant interaction between the swallowing type and trajectory pattern, and laryngeal penetration was the highest for the combination of individual swallow of i-Continuous type and pattern L. In sequential swallowing, the existence of a penetration-prone swallowing pattern combination was an interesting phenomenon relevant to eating management for dysphagic patients; however further study in patient groups is required.