Teaching neuroimages: Compression of the eighth cranial nerve causes vestibular paroxysmia.

A 55-year-old man reported having recurrent spontaneous attacks of rotatory vertigo lasting 1–5 seconds and occurring up to 10 times daily and often associated with attacks of right ear tinnitus for more than 3 years. Caloric testing showed a right peripheral vestibular deficit. Cervical vestibular myogenic potentials showed impaired function of the right saccule. An audiogram was normal. MRI (figure, A and B) showed that the eighth nerve was in contact with the anterior inferior cerebellar artery. Vestibular paroxysmia was diagnosed. Carbamazepine resolved the symptoms but the patient discontinued it due to side effects. The symptoms recurred, and surgery was performed. Intraoperatively, compression of the eighth nerve was found (figure, C and D). He has had no further symptoms and takes no medication. These findings support the view that vascular compression of the root entry zone of the eighth cranial nerve can cause vestibular paroxysmia.