The relationship of the nucleus ambiguus with prognosis of dysphagia in lateral medullary infarction

We investigated whether the prognosis for dysphagia associated with lateral medullary infarction (LMI) may be established using imaging findings, clinical disease type, or associated risk factors. The subjects included 37 men and 3 women with LMI (mean age, 58.5 years old; age range, 36-77 years old). Subjects were assigned to a poor-prognosis group, in which percutaneous endoscopic gastrostomy was required; a good-prognosis group, in which dysphagia improved; and a group without dysphagia. Imaging findings, clinical manifestations, and co-morbidities were compared among these groups. We found that posterolateral lesions in the upper medulla are more important than those affecting the nucleus ambiguus as a prognostic factor. Regarding dysphagia in LMI, lateral parvicellular reticular formation present in this region may cause neuronal intervention. Greater age may be a prognostic factor, but not clinical manifestations or risk factors. Clinical symptoms and signs, such as nystagmus, facial paralysis, and hoarseness may also have a prognostic role, since these are associated with the tipper portion of the medulla, which is anatomically proximal to the inferior cerebellar peduncle. In contrast, nausea and vomiting appeared to have a minimal role in affecting the prognosis.