Clinical Study of 46 Patients with Lateral Medullary Infarction

Background: Lateral medullary infarction (LMI) exhibits a variety of clinical features. Various bulbar symptoms can occur in LMI.

Methods: Neuroradiologic findings of 46 LMI patients were examined. Their infarcts were categorized into the rostral, middle, and caudal groups and were further subdivided into the anteromedial, anterolateral, lateral (L), and posterior regions.

Results: The middle medulla was the most common site (27 patients). Most lesions affected the L region alone (25 patients). Dysarthria and facial palsy occurred significantly more frequently in the rostral group than those in the caudal group. Severe truncal ataxia was significantly more common in the caudal group than that in the rostral group. Twenty-five of the 28 patients with severe truncal ataxia displayed vestibular symptoms; otherwise, the other 3 patients showed absence of vestibular symptoms. Soft palate paralysis occurred at a significantly high frequency in the patients with dysphagia and hoarseness compared with the patients without these 2 symptoms. Segmental sensory disturbance occurred in 5 patients, 4 of whom exhibited atypical patterns.

Conclusions: The results of our comparisons between the rostral and caudal groups were consistent with those of previous studies. The presence of severe truncal ataxia without vestibular symptoms in LMI was atypical. An analysis of the bulbar symptoms indicated that the extent to which soft palate paralysis contributed to dysphagia was associated with the severity of ischemia in the nucleus ambiguus. The present study showed variability in clinical features of LMI, which was related to differences in the severity and the extent of ischemia in the lateral medulla.