Kinetic Modeling of the Hyoid Movement During Swallowing and the Comparison with Surface Electromyographic Activity: A Preliminary Study / 대한연하장애학회지

ABSTRACT

Objective@#The purpose of this study was to understand the mechanism of normal hyoid movement during swallowing by calculating the activity of each muscle involved in the hyoid movement and propose a new kinetic modeling of hyoid movement using videofluoroscopy images. @*Methods@#Eight healthy volunteers with an average age of 56.8 swallowed 2-ml of diluted barium under videofluoroscopy. A video image was digitized to analyze the movement of the hyoid bone. The activity of the muscles acting on the hyoid bone was calculated from the movement of the hyoid bone using kinetic modeling. A surface electromyogram was measured simultaneously with videofluoroscopy, and the muscle force calculated by kinetic modeling was compared with the muscle force measured by surface EMG. @*Results@#The muscles acting on the hyoid bone were divided into three groups according to the direction of force and analyzed. The contraction of the retractor muscle group was observed as a median of 433 ms (95% CI 264-602, P=0.012) earlier than the contraction of protractor muscle group in all subjects. Generally, the peak activity of each muscle group was observed in the order of retractor (0 ms), protractor (592 ms, 95% CI 429-755), and depressor (717 ms, 95% CI 535-899) muscle group. The contraction of the protractor muscle measured by surface electromyography showed an earlier onset latency with a median of 82 2 ms (95% CI 615-102 9, P=0.012 ) compared to the contraction of the protractor muscle calculated by kinetic modeling. @*Conclusion@#Kinetic modeling reflects the pattern of contraction in the order of retractor, protractor, depressor muscle groups, as previously known. And it was possible to evaluate the activity of the retractor muscle, which is difficult to evaluate by electromyogram.