Episodic vertigo frequently occurs in patients suffering from ischemia in the distribution of the vertebrobasilar circulation. It may occur in isolation, with other symptoms of vertebrobasilar insufficiency or with persisting symptoms and signs of infarction of the brain stem and cerebellum. When other symptoms and signs are present, the diagnosis is usually obvious, whereas, when vertigo occurs in isolation it can be difficult to differentiate from more benign disorders involving the inner ear. Typical attacks of ischemic vertigo are abrupt in onset and last minutes. Since the inner ear is supplied by the vertebrobasilar circulation, inner ear symptoms are common with ischemia in this distribution. The labyrinth may be selectively vulnerable because it is an end circulation with minimal collaterals.