Effects of temporary occlusion of a vertebral artery on the human vestibular system

Abstract

✓ Vestibular responses elicited by temporary occlusion of one vertebral artery were observed in 25 cases of intermittent vertebral artery compression (Power's syndrome) during surgical treatment by periarterial denervation of an isolated vertebral artery. This produced manifold varieties of spontaneous nystagmus, ocular movements without noticeable pupillary changes; the ocular manifestations included coarse vertical nystagmus, monocular horizontal nystagmus, convergence nystagmus, and conjugate or disconjugate eye movements. Subjective symptoms were observed in only approximately one half of the cases. These results support the concept that the vestibular nuclei as well as the oculomotor system in the brain stem are particularly sensitive to reduced blood flow through the vertebrobasilar arterial system. Examination of nystagmus under Frenzel glasses proved to be one of the most sensitive tests in evaluating the circulatory status of the brain stem.