Objective: To compare the videofluoroscopic findings between the patients with lateral medullary infarct and middle cerebral artery infarct and to investigate specific findings relevant to lateral medullary infarct.

Method: Among patients with stroke taking videofluoroscopic study for swallowing problems, thirteen patients had a lesion in lateral medulla in imaging study and twenty-six patients in middle cerebral arterial territory. The findings of videofluoroscopic study on two groups were analyzed and compared.

Results: In oral phase, the ability of mastication and bolus formation were better in lateral medullary group. In pharyngeal phase, lateral medullary group revealed significantly impaired triggering of pharyngeal reflex, impaired laryngeal elevation, larger amount of residual materials, repeated swallow, delayed pharyngeal transit time, weaker pharyngeal muscle contraction, and poorer upper esophageal sphincter relaxation. Inadequate relaxation of upper esophageal sphincter was most significant factor in indicating the possibility of lateral medullary infarct (positive predictability 90.0%). Inadequate triggering of pharyngeal swallow indicated least possibility of lateral medullary infarct (negative predictability 92.3%).

Conclusion: Lateral medullary group has the characteristics of more impaired pharyngeal function and better oral function during swallowing than middle cerebral artery group in videofluoroscopic study. Inadequate upper esophageal relaxation and triggering of pharyngeal swallow are the most predictive for lateral medullary infarct.