Vertigo and drop attacks caused by acute transient monocular disequilibrium (Halpern's syndrome).

Among the causes of acute vertigo the syndrome of sensorimotor induction in unilateral disequilibrium (Halpern's syndrome) should be considered. This syndrome was found in a patient and described in detail. The major features of this syndrome are the displacement of vertical and horizontal axes induced by looking with the "affected" eye only, which are further aggravated by applying red filters to the eyes only, which are further aggravated by applying red filters to the eyes and corrected by blue filters. The symptomatology is described and discussed in detail. Theories causing this syndrome are discussed.