Unilateral thalamic infarction and vertical gaze palsy: cause or coincidence?

Although vertical gaze palsy (VGP) is commonly associated with lesions of the rostral mesencephalon, there is some evidence that VGP may also be caused by a unilateral thalamic lesion. The case of a 68-year-old man with persistent upward gaze palsy after a unilateral thalamic infarction, demonstrated on computed tomography and magnetic resonance imaging scans, is presented. Subsequent high-resolution magnetic resonance scanning, however, showed involvement of the rostral mesencephalon as well. The authors suggest that in previous patients with VGP ascribed to a unilateral thalamic infarction, a coexisting mesencephalic involvement may have been missed because of inappropriate imaging techniques. Strong evidence of unilateral thalamic infarction as a cause of VGP is still lacking.