The vestibular labyrinth consists of ? ve compartments: the lateral,
anterior, and posterior semicircular canals, the utricule, and the
saccule. At the beginning of the twentieth century, Robert Bárány
proposed the caloric test as a clinical test of the lateral semicircular
canal. This test enabled clinicians to assess the individual lateral
semicircular canal function easily by using the simple method of
irrigating the external ear canal with cold or warm water and observing
the induced nyst- mus. We believe that the caloric test was a
breakthrough in the ? eld of vestibular research. However, as far as the
other compartments were concerned, there was no simple clinical test
equal to the caloric test for the lateral semicircular canal function.
At the end of the twentieth century, the vestibular evoked myogenic
potential (VEMP) test was proposed as a new method for assessing the
individual saccule function. This test has some unique attributes.
First, it uses sound stimulation, even though it is a test of the
vestibular system. This appears to be a contradiction n-
rophysiologically. As a result, in its early stages there were
controversies conce- ing the origin of the responses. However, such
controversies have been overcome by basic neurophysiological studies and
clinical studies. Above all, sound sensit- ity of the saccular afferents
shown in cats and guinea pigs with single-unit recording methods became
the main supporting evidence. Nowadays, VEMP is one of the routine
clinical tests for balance disorder.
