[Paramedian bithalamic infarct syndrome: report of five new cases].

Five patients were examined suffering from bilateral paramedian thalamic infarction, caused by occlusion of the posterior paramedian thalamo-subthalamic arteries, when they begin from one single pedicle. All cases began with obnubilation or transitory coma, followed by hypersomnia. Four patients showed vertical gaze paralysis, and the fifth vertical nystagmus. In three cases, nuclear lesion of the III cranial nerve was observed along with alteration of the photomotor reflexes, and there was miosis in one case. All were suffering from weakness in one or another limb or facial paresis and generalised acute hypotonia: only one patient had hemihypostesia. All five had dysarthria, ataxy and dysmetria, one had asterixis and two spasmodic crying. Between 5 and 12 months later, one had akinetic mutism and vertical gaze paralysis as the most noteworthy signs. The neuroradiological images show a bilateral ischemic lesion in the paramedian thalamic region, which extends in some cases to the anterior nucleus and in one case to the pulvinars; the lesion continues through the subthalamic regions and the medial part of the mesencephalic tegmentum, with a clear extension to the medial region of the cerebral peduncles in three cases and to the tectum in one case.