Vestibular-evoked myogenic potentials and video head impulse test in cochlear otosclerosis

Background Otosclerosis is one of the most common causes of hearing loss in adults with clinical onset between 20 and 40 years of age. Vestibular symptoms may be the most agonizing and primary symptom in cases with otosclerosis, so the assessment of patients is important. The vestibular-evoked myogenic potentials test (VEMP) is used to assess the saccular and the utricular functions using cervical and ocular vestibular-evoked myogenic potentials (cVEMP and oVEMP), respectively. The video head impulse test (vHIT) which measure vestibulo-ocular reflex (VOR) to rapid impulsive head acceleration in the plane of each semicircular canal (SCC) has allowed quantitative monitoring of each canal function. Methods Twenty subjects with bilateral otosclerosis were studied, ranging in age from 30 to 55 years, divided into two groups. One group consisted of 10 adult patients with bilateral conductive otosclerosis. The second group consisted of 10 adult patients with bilateral mixed otosclerosis. All the patients underwent cVEMP and oVEMP, using a BC 500Hz tone burst stimulus and vHIT in three planes, left anterior right posterior (LARP), right anterior left posterior (RALP), and lateral SCCs. Results The findings indicate statistically significant differences in the peak-to-peak amplitudes of cVEMP and oVEMP in the two studied groups, and the mixed cases had lower amplitudes than conductive cases and a significant increase in p13 latencies. Also, there is a statistically significant difference in the lateral SCC gain between the two groups, as mixed cases had lower gain than conductive cases, but not for anterior or posterior SCCs, with no gain less than 0.8 in all three canals. Conclusion The findings suggested that the saccule is more liable to be affected by cochlear otosclerosis followed by the utricle. The three SCCs are mostly spared.