Recognition of turn degree in vestibular disorder

Abstract

Recently, conventional rotation test (CR-test) is not agreed with important examination for patients of vestibular disorder. In the CR-test, the laterality of the vestibular disorder could not be known because the bilateral semicircular canals are stimulated at the same time when a head turns. In the other hand, the unilateral semicircular canal is stimulated at the caloric test. Therefore, caloric test is more poplar examination than CR-test however caloric test is unpleasant for patients. Observation of nystagmus after turns is important also in the CR-test, therefore patients with forced nystagmus after stimulation feel unpleasantness such as a wide berth. In this report, abnormality of the space perception was shown with quantification by the improved CR-test. This test is not invasive for patient at all, and is available simple using a revolving chair without any special equipment. Recommended movement of a revolving chair is 1/12-1/20 Hz and 90 degrees turn. When the chair is rotated to 90 degrees, the normal and nearly recovered subjects respond as “90 degrees”. In the other hand, patients of vestibular disorder responded the false degrees. Subjective rotation degree when the chair turned at 90 degrees was also recovered to normal after the vestibular function was recovered.