Isolated rotational vertigo due to internal capsular infarction.

Isolated rotational vertigo is most often associated with disorders of the semicircular canals, vestibular nerve, brainstem, or cerebellum but rarely observed following a supratentorial stroke. A 64-year-old man developed sudden onset of vertigo and horizontal right-beating nystagmus with a torsional component in primary and eccentric gazes, unsteady gait, and axial lateropulsion to the right side. Magnetic resonance imaging demonstrated an infarction in the posterior limb of left internal capsule, an unusual cause of the patient's signs and symptoms.