Influence of effortful swallowing on the temporal and kinematic variables in healthy subjects

Abstract

Introduction: We investigated the influence of the effortful swallowing maneuver on the movements of the hyoid bone, the larynx and the epiglottis in healthy subjects. Methods: A total of 41 healthy subjects (20 men, 21 women) swallowed 10ml of diluted barium solution using two swallowing strategies

normal swallowing and effortful swallowing. The frame-by-frame movement of anatomical structures such as the hyoid bone, the larynx and the epiglottis were tracked from digitized videofluoroscopic images. Both temporal and kinematic variables were analyzed. Results: Compared to normal swallowing strategy, effortful swallowing yielded significantly larger vertical displacement of the hyoid bone (17.48±6.07 vs. 13.88±5.48mm

p<0.001), vertical (26.24±8.29 vs. 23.54±6.84mm, p=0.003) and horizontal (8.01±2.89 vs. 6.97±2.42mm, p=0.019) displacement of the larynx. Maximal angle of the epiglottic rotation was larger with effortful swallowing than with normal swallowing (115.19±15.13 vs. 103.30±22.35°

p=0.001). In addition, total durations of hyoid vertical excursions (1.57±0.60 vs. 1.35±0.26sec

p=0.027), hyoid horizontal excursion (1.66±0.52 vs. 1.35±0.22sec

p=0.001), vertical excursion of the larynx (1.60±0.58 vs. 1.34±0.25sec

p=0.012) and epiglottic rotation (1.12±0.53 vs. 0.88±0.17sec

p=0.004) were greater in effortful swallowing maneuver than in normal swallowing Conclusions: The effortful swallowing maneuver extended the hyoid excursion, the laryngeal excursion and the epiglottic rotation in healthy subjects. These results suggest that the effortful swallowing maneuver might have a favorable effect on airway protection.