Changes of VEMP Responses by the Strength of SCM Muscles Contraction and Stimulation Intensities

Park, Hong Ju; Han, Soo Hee; Shim, Dae Bo; Shin, Hyang Ae; Lim, Sang Gyun; Ahn, Jae Yoon; Chung, Yong Soo; Shin, Jung Eun

Abstract

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the effect of the strength of SCM muscle contraction and the intensity of the sound stimulation on the VEMP parameters (amplitude, latency and threshold).
SUBJECTS AND METHOD
Twenty normal subjects were included. Subjects pushed with their jaw against the hand-held inflated cuff to generate cuff pressures of 20, 40 and 60 mmHg and sequential stimulation intensities were applied. Variances of each parameter were analyzed.
RESULTS
There was no significant difference in terms of threshold according to the side and strength of SCM contraction. P1-N1 amplitude demonstrated no significant differences according to the side ; however, the amplitude increased significantly as the cuff pressure and stimulation intensity increased. Interaural amplitude difference ratios showed an increased difference at 20 mmHg when compared to those at 60 mmHg. There was neither a cuff pressure effect, nor stimulation intensity effect when considering the P1 latencies. As for the N1 values, there was no stimulation intensity effect but there was a delayed latency at 20 mmHg when compared to those at 40 or 60 mmHg. Interaural latency difference of N1 latencies did not differ significantly according to the cuff pressure ; however, there was an increased difference at 20 mmHg when compared to those at 40 or 60 mmHg.
CONCLUSION
This study shows that VEMP response is influenced by the cuff pressure and stimulation intensity, and we recommend to get each VEMP parameter using this feedback method in the clinical setting.