Sonographic analysis of laryngeal elevation during swallowing

Background: Swallowing disorders are common symptoms in many neurological diseases. The aim of this pilot-study was to analyse vertical laryngeal excursion during swallowing non-invasively using ultrasound sonographic techniques in patients with dysphagia compared with healthy volunteers. Methods: Data were obtained from 42 healthy volunteers (mean age: 57 ± 19 years) and 18 patients (mean age: 63 ± 8 years) with dysphagia due to different neurological diseases using a 7.5 MHz linear array probe, which was placed in longitudinal position above the larynx. This allowed visualization of the contour and the acoustic shadow of the hyoid bone and the thyroid cartilage. The distance between the hyoid bone and the upper end of the thyroid cartilage during laryngeal elevation was readily assessed by video-mode function. Results: In healthy subjects we found a mean distance of 220 (± 30) mm at rest; the shortest distance during swallowing of 5 or 10 ml water was 85 (± 11) mm and represents a reduction of 61 % (± 3) under physiological conditions. The mean relative laryngeal elevation in the patients with neurogenic dysphagia was reduced to only 42 % (± 10) (p < 0.0001). Conclusions: Ultrasound is a viable and non-invasive method in the investigation of laryngeal elevation during swallowing. It allows direct visualization of impaired laryngeal motion in patients with neurogenic dysphagia.