Bone conduction stimulated VEMPs by using the B250 transducer to assess the nerve of origin of sporadic vestibular schwannomas

Vestibular evoked myogenic potentials (VEMPs) are a tool to assess otolith function and a component of sensor specific vestibular diagnostics. The aim of the present study was to measure VEMP trough bone conducted (BC) stimulation using the B250 prototype and to report amplitudes, latencies and threshold levels for patients before resection of a sporadic unilateral vestibular schwannoma (VS) in order to assess function regarding to the reported nerve of origin. Twenty-seven participants (9 male/18 female) with a mean age of 55.9 years (SD: 10.8) were included for the analysis. In the side contralateral to the tumor, in 24 (89%) of the patients cVEMP could be measured, while oVEMP were recordable in 20 patients (74%). For patients with inferior vestibular nerve of origin (n = 11), cVEMP amplitudes of the affected side were significantly lower as compared to the non-affected side, while the force threshold level was increased. No statistically significant differences were observed for neither, oVEMP amplitudes nor threshold levels in the group with superior vestibular nerve of origin (n = 7). Across groups, p13 latency was significantly increased in the affected ear while all other VEMP latencies were not different between the ears. The B250 transducer was applicable to all participants of the clinical cohort. The sample size, however, was too low for a reliable statistical analysis and only allowed for exploratory analysis.