Cortical Function Changes During Swallowing in Patients With Dysphagia in Lateral Medullary Syndrome

The goal of this observational study is to detect the alteration of cortical activation and functional connectivity during swallowing in patients with Lateral Medullary Syndrome (LMS) dysphagia by functional near infrared spectroscopy (fNIRS). The main questions it aims to answer are: * The alteration of cortical activation during swallowing in patients with LMS compared with healthy subjects. * The alteration of cortical functional connectivity during swallowing in patients with LMS compared with healthy subjects. fNIRS will be used to detect cortical activation and functional connectivity during swallowing tasks in LMS patients and healthy subjects, and to compare the differences between patients and healthy subjects.