Altered sensorium, confusion, and vertical gaze paresis: the top of the basilar syndrome

The term "top of the basilar" has been used in reference to a group of signs and symptoms of midbrain, diencephalic, and posteroinferior hemispheric dysfunction. It has been attributed to ischemia in the territory of second- and third-order vessels that arise from the uppermost portion of the basilar artery. We report our experience with four patients who had alteration of consciousness, confusion, and vertical gaze paresis accompanied by other physical abnormalities. Extensive evaluation did not help in documenting the lesions or in understanding their pathogenesis. The top of the basilar syndrome is a not uncommon form of stroke and carries a variable prognosis. Treatment by anticoagulation may prevent further infarction in selected patients who are seen early.