Isolated vestibular syndromes due to brainstem and cerebellar lesions.

Dizziness/vertigo is the most common symptoms of posterior circulation strokes. Isolated vestibular symptoms and signs without other neurologic deficits have been found in infarctions involving the brainstem and cerebellum. In the brainstem, infarctions responsible for isolated vestibular syndrome are usually restricted to the dorsal portion that contains the vestibular nucleus and the nucleus prepositus hypoglossi. Cerebellar lesions confined to the flocculus, tonsil, and nodulus also produce isolated vertigo and imbalance. The cerebellar peduncle, as a conduit between the brainstem and cerebellum, can also produce isolated vestibular syndrome when damaged. Recognition of these isolated central vestibular syndromes aids in defining the function of each structure and in localizing the involved neural structures based upon the vestibular and ocular motor findings.