Classification of vestibular brainstem disorders according to vestibulo-ocular reflex planes.

Evidence is presented for a preliminary and speculative classification of central vestibular disorders of the brain stem according to the three major planes of action of the vestibuloocular reflex (VOR), 1. Disorders of the VOR in horizontal (yaw) plane: horizontal nystagmus-vertigo; 2. Disorders of the VOR in sagittal (pitch) plane: downbeat or upbeat nystagmus-vertigo; 3. Disorders of the VOR in frontal (roll) plane: ocular tilt reaction and lateropulsion. [ABSTRACT FROM AUTHOR]