[A case of "ping-pong ball eye movement (author's transl)].

We experienced a rare and peculiar eye movement in a comatose patient with ruptured intracranial aneurysm. The patient's eyes moved quickly and irregulary from one extreme position to the other with whirling and bounding components. Such abnormal eye movement occasionally halted, but abruptly reappeared. We named this abnormal eye movement which had never been reported before, "ping-pong eye movement". Neuropathological study revealed a subarachnoid hemorrhage and the diffuse infarction in the right remporal lobe, and a smal clot in the fourth ventricle without specific findings in the brainstem and the cerebellum. Consideration was made that the hemorrhage in the fourth ventricle resulted in a hyper-irritable state in the fastigial nuclei, from which the abnormal discharges were driven to the reticular formation, the vestibular nuclei, the MLF, and the oculomotor complexes. We conclude that this "ping-pong" ball eye movement" might be the appearance of epilepsy in the eyes, due to the epileptogenic focus of the fastigial nuclei.