Prognostic utility of submental B/M-Mode ultrasonography for swallowing function assessment in post-stroke pharyngeal dysphagia: a preliminary study

Objective To evaluate the prognostic value of hyoid bone kinematic parameters measured via submental B/M-mode ultrasonography in post-stroke pharyngeal dysphagia, aiming to identify reliable predictors of swallowing recovery. Methods This study included 46 stroke patients with pharyngeal dysphagia, diagnosed via videofluoroscopic swallowing study (VFSS), and treated at the Department of Rehabilitation Medicine, Affiliated Brain Hospital of Nanjing Medical University (June 2020–August 2024). Swallowing function was assessed using seven pharyngeal phase parameters from the Videofluoroscopic Dysphagia Scale (VDS) at baseline and post-rehabilitation. Patients were stratified into favorable ( n = 26) and unfavorable ( n = 20) prognosis groups based on post-treatment VDS and Functional Oral Intake Scale (FOIS) scores. Submental B/M-mode ultrasonography quantified hyoid bone displacement parameters pre- and post-rehabilitation, including maximum displacement, anterior displacement, superior displacement, total movement duration, and hyoid-thyroid cartilage approximation ratio (ASR). Result No significant differences were observed between groups in baseline characteristics. Post-treatment, the favorable group showed significantly lower Rosenbek scores (p = 0.000) , reduced VDS scores (p = 0.000) , and decreased feeding tube dependency (p = 0.000) . Post-treatment, the favorable group exhibited greater anterior displacement (p = 0.011) , higher ASR (p = 0.000) , and shorter total movement duration ( p = 0.005 ). Logistic regression identified hyoid anterior displacement (odds ratio (OR) = 9.539, p = 0.011 ) and ASR (OR = 14.238, p = 0.001 ) as independent prognostic predictors. ROC curve analysis indicated that hyoid anterior displacement (area under the curve (AUC) = 0.720) and ASR (AUC = 0.816) were significant discriminators of favorable outcomes, with optimal cutoff values of 0.865 cm (92.3% sensitivity, 50.0% specificity) and 31.5% (84.6% sensitivity, 65.0% specificity), respectively. The combined model further improved predictive accuracy (AUC = 0.854, 84.6% sensitivity, 85.0% specificity). Conclusion Impaired hyoid anterior displacement and reduced ASR are critical pathophysiological mechanisms in post-stroke dysphagia. Combined assessment of these parameters provides significant clinical utility for prognosis and treatment planning.