Comparison of short tone burst-evoked and click-evoked vestibular myogenic potentials in healthy individuals.

BACKGROUND Vestibular evoked myogenic potential (VEMP) is one of the clinical tools to evaluate vestibular function. The VEMP can be recorded from sternocleidomastoid muscle by auditory stimulation with various sound stimuli. The aim of this study was to compare the VEMP responses evoked by short tone burst (STB) with those evoked by click stimuli in healthy young individuals. METHODS Twenty-two healthy volunteers (11 males, 11 females; 44 ears), with ages ranging from 17 to 30 years were enrolled in this study. Subjects were instructed to lie in supine position and elevate their heads unsupported. The VEMP was recorded using 500Hz STB and then click sound stimuli to each ear. The latency p13, n23, peak-to-peak p13-n23 amplitude and VEMP asymmetry ratio (VAR) were obtained for further analysis. RESULTS The VEMP responses were present in all subjects. The latencies p13 and n23 of STB-VEMP were significantly longer, and the p13-n23 amplitudes were significantly greater for STB-VEMP (p<0.05, paired t test), as well. The VAR, however, showed no significant difference between the 2 stimuli. The latency n23 of click VEMP in our study was significantly different from that of 1 of the other studies (p<0.05). CONCLUSION The VEMP responses were significantly different between the stimuli of STB and click, and the norms of different stimuli should be established for clinical interpretations. For clinical diagnosis using VEMP, we recommend STB stimuli because the latencies and amplitudes of click were significantly different among several labs, including ours.