Characteristics and Prognostic Factors of Swallowing Dysfunction in Patients with Lateral Medullary Infarction

Objectives: Lateral medullary infarction mainly impairs the pharyngeal phase of swallowing. We aimed to investigate the utility of the assessment tools of swallowing function in patients with lateral medullary infarction and to determine the factors that could predict the outcomes of swallowing function. Materials and Methods: 15 patients with lateral medullary infarction who were admitted to Suiseikai Kajikawa Hospital between August 1, 2016, and March 31, 2020 (age 62.7 +/- 14.8 years, 5 women) were enrolled in this prospective study. The diagnosis was made using brain magnetic resonance imaging. We analyzed the factors associated with severe swallowing dysfunction, which was defined as the necessity for tube feeding on the 90th day from admission, with multiple logistic regression analysis. Results: Multivariate analyses identified the repetitive saliva swallowing test, modified water swallowing test, and vertical spread of stroke lesions as independent significant factors affecting severe swallowing dysfunction (p = 0.002, 0.016, and 0.011, respectively). The sub-scores of the pharyngeal phase of the Mann Assessment of Swallowing Ability were also significantly associated with severe swallowing dysfunction (p < 0.001). However, tongue pressure, severe passage pattern abnormality on videofluoroscopic examination, and vertebral artery dissection were not significantly associated with swallowing dysfunction. Conclusions: Since lateral medullary infarction presents with swallowing dysfunction mainly in the pharyngeal phase, tools that can be used to evaluate the pharyngeal phase of swallowing, such as repetitive saliva swallowing test and modified water swallowing test, are moreuseful than measurement.