Vestibular evoked myogenic potentials using simultaneous binaural acoustic stimulation.

The aim of this study is to investigate the feasibility of recording vestibular evoked myogenic potential (VEMP) using simultaneous binaural acoustic stimulation (B-VEMP), and compare it with that using monaural acoustic stimulation (M-VEMP). Seven healthy volunteers were evoked by initial B-VEMP test and subsequent M-VEMP test, whereas vice versa in another 7 volunteers. All 14 subjects demonstrated both B-VEMPs and M-VEMPs, without significant difference in the latencies of p13 and n23. When using interaural amplitude difference (IAD) ratio for interpreting amplitude, B-VEMPs did not differ significantly from that of M-VEMPs. Hence, B-VEMPs can produce information equivalent to M-VEMPs in terms of response rate, latencies, and IAD ratio in healthy subjects. Likewise, similar results were also shown in the patients with unilateral Meniere's disease. In conclusion, B-VEMPs provide neither different information nor less variability, as compared with M-VEMPs. In addition, B-VEMPs can offer information on unilateral inner ear (saccular) pathology similar to that by M-VEMPs. Furthermore, recording from binaural stimulation can be used as a possibly more convenient mode compared with two monaural recordings, especially when testing young or old or disabled patients, since a continuous muscular effort is required during recording.