The Effects of Test Positions and Acoustic Stimulations on the Vestibular Evoked Myogenic Potentials

ABSTRACT

BACKGROUND AND OBJECTIVES: Vestibular evoked myogenic potentials (VEMP) have become a good diagnostic tool to evaluate the integrity of the vestibulocollic reflex. To investigate the standard recording of VEMP response in normal hearing subjects, the authors studied the effects of test positions and different acoustic stimulations on the VEMP. SUBJECTS AND METHOD: We performed VEMP on both ears of thirty normal hearing volunteers. Three acoustic stimulations (clicks and 500 Hz and 1,000 Hz short tone bursts) and four test positions were presented alternately to evoke VEMP. The latencies of peak p13 and n23, p13n23 interpeak latency (IPL) and amplitude were measured by EMG equipment and compared by statistical program. We also made up questions for the compliance of the test positions. RESULTS: The effects of test positions p13 latency had no significant difference on all test positions except between test position 2 and 4, n23 latency and p13n23 IPL had shortest waveform on test position 2, p13n23 amplitude had the largest waveform in test position 4. Acoustic stimulations on all test positions were influenced that clicks had shorter waveform about 2-3 ms than STBs on p13 latency and n23 latency, STBs had larger waveform than clicks on p13n23 amplitude. And the compliance of the test positions exhibited highest comfort in test position 1. CONCLUSION: Test position 1 had higher VEMP response rates and compliance, 500 Hz STB had a largest p13n23 amplitude. Therefore we recommend that the ideal conditions were position 1 and 500 Hz STB for acoustic stimulations to evoke VEMP.