Paroxysmal spontaneous nystagmus and vertigo evoked by lateral eye position

Prolonged lateral eye position to the extreme left for 5 to 20 seconds, without vestibular stimulation, induced intense attacks of nystagmus and rotational vertigo lasting 50-90 seconds in a patient. During the attacks the nystagmus beat to the right and counterclockwise, while the patient could look freely around. Clinical data were suggestive of repeated strokes in the vertebrobasilar territory, mainly affecting the right dorsolateral medulla oblongata including the vestibular nuclei. A paroxysmal attack of nystagmus and vertigo evoked by voluntary lateral eye position is an unusual clinical finding. This is discussed in the light of multisensory integration within the vestibular system, which also includes eye position information.