[Illusion of visual tilt: a case].

A 21-year-old man experienced sudden and intense rotational vertigo. A moment later, he was amazed to see the whole visual world rotate clockwise progressively by about 160 degrees. On the following day, the visual tilt was only 30 degrees, and it soon receded completely, while headache appeared. CT scan, magnetic resonance imaging, vertebral arteriography, and cerebrospinal fluid analysis were normal, and the aetiology could not be ascertained. Illusions of visual tilt are an unusual consequence of disorders affecting the vestibular system. The locus of the impairment is usually in the brainstem, particularly in association with Wallenberg's syndrome. However, the peripheral vestibular pathways or the vestibular projections into the cerebral cortex may occasionally be involved. In the latter case, the visual tilt is part of a vestibular epileptic seizure.