LAUSR

A 52-year-old man presented with a 2-year history of sensory symptoms in his left shoulder and upper arm, as well as dizziness and almost fainting by extensively turning his head to the left. His relevant medical history included hypertension, thyroidectomy, and human immunodeficiency virus infection. Neurological examination showed neither signs of a unilateral vestibulopathy, nor nystagmus at rest, by gaze, or head-shaking. However, a horizontal spontaneous nystagmus was detected by turning the head to the left. Otherwise, the neurological examination showed no abnormalities. Magnetic resonance and computed tomographic imaging of the cervical spine and brain showed a left-sided foraminal C3–4 disk herniation with uncarthrosis, and a focal, nonsignificant stenosis of the vertebral artery (VA) at the same level (Fig, A, arrow). The right VA ended in the posterior inferior cerebellar artery, not contributing to the basilar artery supply. With Doppler ultrasound, a functional stenosis of the left VA was suspected during rotation of the head.