[A small cortical infarction showing dysarthria and left hypoglossal paresis]

We reported the case of a 77-year-old female who presented with left hypoglossal paresis and dysarthria due to a small cortical infarction. She was admitted to our hospital because of the sudden onset of dysarthria. A neurological examination revealed deviation of the tongue to the left and paretic dysarthria without motor paralysis in the extremities. Diffusion-weighted imaging of the brain revealed a slightly high signal intensity at the right precentral gyrus, indicating an acute brain infarction in the motor cortex. Carotid MR angiography revealed atherosclerotic changes seen at the right internal carotid artery, suggesting an atherothrombotic brain infarction with artery-to-artery embolism. The patient was discharged on the 17th day of hospitalization with slight left hypoglossal paresis. Isolated cranial nerve paresis is a rare symptom in stroke patients. Furthermore, in this patient, dysarthria in this case was more obvious than that of peripheral hypoglossal palsy. Recent electrophysiological has investigation indicates that the corticolingual tract plays a significant role in the presence of pure dysarthria in the stroke patients. This case indicate that cortical infarction in the primary motor cortex may produce isolated hypoglossal nerve paresis and dysarthria due to disruption of the corticolingual tract.