Bone Conduction Stimulated VEMP Using the B250 Transducer

OBJECTIVE: Bone conduction (BC) stimulation is rarely used for clinical testing of vestibular evoked myogenic potentials (VEMPs) due to the limitations of conventional stimulation alternatives. The aim of this study is to compare VEMP using the new B250 transducer with the Minishaker and air conduction (AC) stimulation. METHODS: Thirty normal subjects between 20 and 37 years old and equal gender distribution were recruited, 15 for ocular VEMP and 15 for cervical VEMP. Four stimulation conditions were compared: B250 on the mastoid (F(M)); Minishaker and B250 on the forehead (F(Z)); and AC stimulation using an insert earphone. RESULTS: It was found that B250 at F(M) required a statistically significant lower hearing level than with AC stimulation, in average 41 dB and 35 dB lower for ocular VEMP and cervical VEMP, respectively, but gave longer n10 (1.1 ms) and n23 (1.6 ms). No statistical difference was found between B250 at F(M) and Minishaker at F(Z). CONCLUSION: VEMP stimulated with B250 at F(M) gave similar response as the Minishaker at F(Z) and for a much lower hearing level than AC stimulation using insert earphones.