Oral Session 3: Vestibular Function

The human vestibular system comprises five motion detectors, being the three semicircular canals for rotation detection and two otolith organs for linear acceleration detection. Whereas Unilateral Centrifugation (UC) [1] is used for over a decade to evaluate the utricle, the ocular vestibular evoked myogenic potential (oVEMP) test is a very recent test, claiming to be also a utricular test. The current study investigates to which extent there is a similarity between the asymmetry for utricular and horizontal canal function, using ENG, UC and oVEMP. We tested 257 patients with vestibular problems, visiting the department of otolaryngology in the Antwerp University Hospital. After the clinical investigation, the patients were referred to AUREA where either ENG and oVEMP was performed (N = 177), either ENG and UC (N = 80). For the ENG data, we used caloric asymmetry (%) as the outcome variable, based on the Jongkees formula for the slow component velocity at maximum. For UC testing we used utricular asymmetry, based on the ocular counter rolling, and for oVEMP we used the asymmetry between right and left side amplitude of the EMG signal of the inferior oblique muscle upon bone vibration with a Bruel and Kjaer minishaker at the forehead. Results: None of the correlations (ENG – UC) or (ENG – oVEMP) was statistically significant, with R values below 10%. These results indicate that evaluation of the function of horizontal semicircular canal and the otoliths is very independent, and conclusions on asymmetry in one system due to a lesion are not valid for the other system. Reference