Can We Improve Pressure Feedback Methods in Vestibular Evoked Myogenic Potentials by Applying Custom Pressures?

OBJECTIVE The aim of the present study was to use constant and customized pressure levels to improve the feedback method of the blood pressure cuff technique in order to decrease intra-subject and inter-subject variability. MATERIALS AND METHODS The study was conducted in two stages. In the first stage, the relationship between the pressure level generated in the blood pressure cuff and electromyographic response in the sternocleidomastoid (SCM) muscle was investigated. In the second stage, vestibular evoked myogenic potential (VEMP) measurements were made using a custom-built VEMP chair at a constant pressure level of 40 mmHg (P40) or at 50% of the maximum pressure (Pmax50%) that could be generated by the SCM muscle. RESULTS VEMP measurements were performed on 100 volunteers consisting of 48 males and 52 females whose ages were between 20 and 68 years. The response rate was 41% on a subject basis and 53% on an ear basis. Response rates were similar in males and females, and they decreased with age. The response rate was significantly lower in 11% of the volunteers who could not generate the stipulated 80 mmHg pressure level. Response rates obtained with P40 and Pmax50% were similar, and p13 and n23 latencies and p13-n23 amplitudes obtained from both sides were also similar. Amplitudes were higher in Pmax50% measurements compared to P40, and amplitudes obtained with P40 levels showed greater variance compared to Pmax50%. CONCLUSION The use of Pmax50% provided reduced variation compared to P40; however, it did not have significant clinical implications. Further studies are needed for the control of many factors that are related to amplitude variability.