Vestibular Evoked Myogenic Potentials Produced by Stimulation with 500 Hz-tone Burst

Bae, Woo Yong; Hwang, Chan Ho; Heo, Seung Deok; Lee, Tae Hoon; Jang, Yoon Seok; Ahn, Joong Ki; Lee, Hyun Jik; Kim, Jae Ryong

Abstract

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potential (VEMP) is muscle reflex caused by surface electrodes following repeated high-intensity auditory stimulation. The current study attempted to determine whether VEMP can be consistently evoked from the sternocleidomastoid muscle (SCM) by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst.
SUBJECTS AND METHOD
Air-conducted and bone-conducted VEMPs in response to 500 Hz-tone burst were recorded from the SCM of 13 normal volunteers. Subjects were seated on their chairs and made to hold their heads turned up as far as possible towards the side, contralateral to the stimulated ear voluntarily. Two different sound durations (rise/fall time=2 msec, plateau time=2 msec[2/2] and rise/fall time=5 msec, plateau time=5 msec[5/5]) were presented through a insertphone or bone vibrators. Latencies and amplitudes of p13 and n23 responses were measured.
RESULTS
All normal volunteers showed p13-n23 responses to 50 dB bone-conducted tone burst as well as to 100 dB air-conducted tone burst. The values of latency of p13 and n23 were the most reliable at 5/5 air-conducted in evaluation by coefficiency of variance. Mean p13 and N23 latencies by airconducted tone burst were significantly longer than those of bone-conducted. Mean p13-n23 amplitudes by air-conducted tone burst were significantly larger than those by bone-conducted at 2/2 sound duration.
CONCLUSION
VEMP could be consis-tently evoked by the 100 dB air-conducted and 50 dB bone-conducted 500 Hz-tone burst, especially at 5/5 air-conducted.