Dynamic suprahyoid muscle ultrasound in assessing oropharyngeal dysphagia in neurological disorders.

Background: Appropriate evaluation and management of dysphagia are essential in neurological disorders. However, there is currently a lack of a simple yet reliable method for dysphagia evaluation.

Aim: This study aimed to investigate the usefulness of new dynamic M-mode ultrasonography (US) parameters of suprahyoid muscle (SHM) to evaluate dysphagia.

Design: Prospective observational, cross-sectional study.

Setting: Inpatient setting at neurology department of tertiary medical center.

Population: A total of 89 patients with dysphagia and 175 healthy volunteers were enrolled in the study. Patients were subdivided into mild and severe dysphagia groups depending on the need for dietary changes and disease classification, which included amyotrophic lateral sclerosis, peripheral neuromuscular diseases, and stroke.

Methods: Dynamic M-mode US was performed during swallowing to obtain the SHM thickness (the baseline thickness of the SHM), SHM displacement (peak-to-peak amplitude of SHM movement), SHM difference (SHM displacement - SHM thickness), SHM ratio (SHM displacement/SHM thickness), peak-to-peak time, and total duration. A videofluoroscopic swallowing study (VFSS) was performed.

Results: Significant differences were found in SHM displacement and SHM difference according to dysphagia severity (P<0.001). The SHM ratio, total duration (P<0.001), and peak-to-peak time (P=0.001) differed significantly according to the patients' underlying diseases. The pharyngeal delay time and penetration-aspiration scale from the VFSS demonstrated significant negative correlations with SHM displacement and difference (P<0.001). By combining SHM difference and total duration, patients with dysphagia could be distinguished from healthy controls, with the highest negative predictive value of 95.6%.

Conclusions: Dynamic M-mode US of the SHM provided added value in evaluating the severity of dysphagia and differentiating swallowing mechanics of dysphagia related to underlying neurological disorders.

Clinical rehabilitation impact: Dynamic M-mode US of the SHM can serve as a supportive tool for rapid screening and repetitive follow-up of patients with dysphagia, which would contribute to dysphagia rehabilitation in patients with various neurological disorders.