OBJECTIVE: A novel method was employed to control the sternocleidomastoid muscle contraction level during vestibular evoked myogenic potential (VEMP) measurement. STUDY DESIGN: A prospective study to measure the normal VEMP response. SETTINGS: A pressure feedback device composed of a firm rubber bulb and a pressure gauge was employed to monitor the muscular contraction level during measurement. METHODS: Nineteen normal-hearing subjects (12 males; mean age 34.0 ± 7.7 years) were tested. Subjects were instructed to position the chin on the rubber bulb and use the neck flexors to maintain a pressure of 120 mm Hg during the measurement. MAIN OUTCOME MEASURES: The P13 latencies, N23 latencies, and P13-N23 amplitudes were recorded. In nine subjects, the reproducibility of the technique was tested weekly for 3 consecutive weeks. RESULTS: The average (± SD) latency of P13 was 13.97 ± 1.33 ms, and the latency of N23 was 24.03 ± 1.79 ms. The average amplitude was 66.89 ± 44.1 μV. There was no significant difference between right and left ears in P13 latencies, N23 latencies, and P13-N23 amplitudes. In nine subjects, the average measured interclass correlation coefficient was 0.97 in amplitude, 0.8 in P13 latency, and 0.93 in N23 latency in three consecutive weekly measurements. CONCLUSIONS: The chin-rest pressure feedback method is easy to perform during VEMP testing. Subjects can maintain a constant level of sternocleidomastoid contraction and neck flexion to facilitate this response with a high degree of test-retest reliability. This technique provides a means to compare VEMPs across different clinical scenarios over time.
OBJECTIVE: A novel method was employed to control the sternocleidomastoid muscle contraction level during vestibular evoked myogenic potential (VEMP) measurement. STUDY DESIGN: A prospective study to measure the normal VEMP response. SETTINGS: A pressure feedback device composed of a firm rubber bulb and a pressure gauge was employed to monitor the muscular contraction level during measurement. METHODS: Nineteen normal-hearing subjects (12 males; mean age 34.0 ± 7.7 years) were tested. Subjects were instructed to position the chin on the rubber bulb and use the neck flexors to maintain a pressure of 120 mm Hg during the measurement. MAIN OUTCOME MEASURES: The P13 latencies, N23 latencies, and P13-N23 amplitudes were recorded. In nine subjects, the reproducibility of the technique was tested weekly for 3 consecutive weeks. RESULTS: The average (± SD) latency of P13 was 13.97 ± 1.33 ms, and the latency of N23 was 24.03 ± 1.79 ms. The average amplitude was 66.89 ± 44.1 μV. There was no significant difference between right and left ears in P13 latencies, N23 latencies, and P13-N23 amplitudes. In nine subjects, the average measured interclass correlation coefficient was 0.97 in amplitude, 0.8 in P13 latency, and 0.93 in N23 latency in three consecutive weekly measurements. CONCLUSIONS: The chin-rest pressure feedback method is easy to perform during VEMP testing. Subjects can maintain a constant level of sternocleidomastoid contraction and neck flexion to facilitate this response with a high degree of test-retest reliability. This technique provides a means to compare VEMPs across different clinical scenarios over time.