Abstract

A quite number of dizzy patients have symptoms suggestive of abnormal otolith function. However, only the pathology of the lateral semicircular canal is well investigated. Conventional laboratory tests to evaluate objective vestibular function, such as Caloric test and rotation test, are tests for the semicircular canals detecting angular acceleration, especially in yaw plane. Considering each vestibular system detects 2 different types of stimuli (angular acceleration and linear acceleration), otolith function test seems to be necessary for comprehensive examination of the patients. Up to now, there are few otolith functional tests useful in clinical settings. Off vertical axis rotation (OVAR) can be used to get information on vestibulo-ocular reflex, including the semicircular reflex, the otolith-ocular reflex, and semicircular canal-otolith interaction. In this section, OVAR will be introduced.