Abstract
A comparative study was conducted for clinical symptoms and MRI findings in 8 cases of cortical central facial monoparesis, and the somatotopy in the precentral motor gyrus was discussed. Six cases with cortical infarction and one case each with subcortical hemorrhage and metastatic brain tumor were included in this study. The precentral gyrus was arbitrarily divided into 3 segments, the upper, middle and lower one-third, between the longitudinal cerebral fissure and Sylvian fissure on a coronal MRI scan through the precentral gyrus. The lesions in all cases were situated in the middle segment of the precentral gyrus, and none extended into the upper one-third. Two cases with complicated facial palsy had localized lesions in the middle segment, three cases with dysphagia, dysarthria, and lingual paresis had more extensive lesions in the middle and lower one-third, and the remaining three cases with lesions involving the deep white matter also exhibited unilateral spatial neglect or aphasia. None of the 8 cases showed a discrepancy between voluntary and emotional facial movements, and it was inferred that the neural pathways for these two different types of motor control of the facial muscles run adjacent to each other in the vicinity of the precentral gyrus.
