Ultrasonographic evaluation of hyoid-larynx approximation in dysphagic stroke patients

Hyoid-larynx approximation is an essential part of the swallowing process, and is related to airway protection. We aimed to evaluate the reliability of ultrasonographic examination of hyoid-larynx approximation and measure the approximation in stroke patients with or without dysphagia. Fifteen normal subjects and 40 stroke patients with or without dysphagia admitted to the Department of Rehabilitation Medicine of a tertiary hospital between July 2006 and February 2007 participated in this study. The distance between the thyroid cartilage and hyoid bone during swallowing was measured by ultrasound. Hyoid-larynx approximation was defined as the distance obtained by subtracting the shortest distance between the hyoid bone and thyroid cartilage during swallowing from the initial resting distance. Ten stroke patients with dysphagia also underwent standard videofluoroscopic swallowing study (VFSS). The change percentage of hyoid-larynx approximation was very similar between ultrasonographic examination and VFSS. There was no significant difference in resting distances between the thyroid cartilage and hyoid bone between normal subjects and stroke patients with or without dysphagia. Among stroke patients, hyoid-larynx approximation was less in the dysphagia group than in the nondysphagia group. In conclusion, ultrasound can quantitatively measure hyoid-larynx approximation with good reliability. Hyoid-larynx approximation was significantly reduced in stroke patients with dysphagia.