Abstract
Vestibular evoked myogenic potentials are tests used to evaluate the integrity of the vestibular system. In this study, we aimed to assess cervical and ocular vestibular-evoked myogenic potentials in patients who underwent CyberKnife treatment for vestibular schwannoma.
The study included 23 patients who received Cyberknife treatment for VS and 26 healthy patients without complaints. The patients were given a 97 dB, 500 Hz tone-burst stimulus using monaural air conduction with the ICS-CHARTER EP 200 audiometry device, and cervical and ocular vestibular-evoked myogenic potential tests were applied. In analyzing the results, we assessed the failure rates in obtaining vestibular-evoked myogenic potential responses and the mean and standard deviation values of P1 latency, N1 latency, P1-N1 interval, and P1-N1 interpeak amplitude, and calculated the amplitude asymmetry ratio.
When comparing sick and healthy ears within the patient group, a statistically significant difference in non-response rates was found for both cervical and ocular vestibular-evoked myogenic potential tests. Comparing the patient group to the control group based on the vestibular-evoked myogenic potentials asymmetry rate revealed significant differences in both cervical and ocular vestibular-evoked myogenic potentials. Upon examining the ocular vestibular evoked myogenic potential responses, only a significant difference was noted in P1 latency. When analyzing the patient group by hearing level, ocular vestibular-evoked myogenic potential responses were statistically significantly reduced among patients with hearing levels greater than 60 dB. Conversely, no significant difference was observed as tumor size increased, and abnormalities in cervical vestibular-evoked myogenic potentials and ocular vestibular-evoked myogenic potentials responses also increased in patients with a medial tumor location.
The vestibular-evoked myogenic potential test is a noninvasive, easy-to-perform test method for evaluating vestibular functions in VS patients.