[Supranuclear vertical gaze palsy: bilateral thalamo-mesencephalic lesions demonstrated by MRI]

The exact location for the major control center of the vertical gaze, which is referred to as rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), has been documental in a few autopsy studies. However, CT in some of the case reports of vertical gaze palsy have not clearly delineated this nucleus and its nearby complex anatomical structures. Discrete small, bilateral, symmetric infarcts in the thalamo-mesencephalic junction were demonstrated by MRI in a 59-year-old female patient who had sustained vertical gaze palsy over a period of nine years. Neurological examination revealed severe supranuclear combined downward and upward vertical gaze palsy, incomplete convergence, and slight limitation in adduction of the right eye. There was neither ptosis, pupillary disturbance, nor any further abnormalities of horizontal eye movements. The vertical vestibulo-ocular reflex was maintained, being similar to the other reported cases of vertical gaze palsy. MRI has advantages over CT in demonstrating lesions in the thalamo-mesencephalic junction in the cases of vertical gaze palsy, because clearer sagittal images can be obtained.