This study investigated the effects of Mendelsohn maneuver with three-dimensional kinematic analysis. Nine female speech-language pathologists (nine females, mean ± SD 27.1 ± 3.5 years old) underwent 320-row area detector scan during swallows of 4-ml nectar-thick liquid using with no maneuvers (control) and with Mendelsohn maneuver (MM). Critical event timing (hyoid, soft palate, epiglottis, laryngeal vestibule, true vocal cords (TVC), UES), hyoid and laryngeal excursion, cross-sectional area of UES, and volume of pharyngeal cavity and bolus were measured and compared between two swallows. In MM, all the events were significantly prolonged with delayed termination time (p < 0.05) except UES opening. The onset, termination, and duration of UES opening were not significantly affected by MM nor was timing of bolus transport. The hyoid bone was positioned significantly higher at maximum displacement (p = 0.011). Pharyngeal constriction ratio was 95.1% in control and 100% of all subjects in MM. Duration of minimum pharyngeal volume was significantly longer in MM than in control (p = 0.007). The MM produces several distinct changes in the kinematics of swallowing in healthy subjects with no dysphagia. The changes in the timing and magnitude of hyoid displacements and prolonged closure of the pharynx during swallowing suggest the utility of MM for improving the safety and efficiency of swallowing in selected cases.
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