Sound evoked triceps myogenic potentials

OBJECTIVE: To determine if a sound evoked myogenic potential could be obtained from the triceps with the recording and stimulus parameters routinely used to obtain a vestibular evoked myogenic potential (VEMP) from the sternocleidomastoid. STUDY DESIGN: Prospective study of myogenic potentials recorded from the triceps in healthy subjects. We used a monaural acoustic stimulus and measured the unrectified myogenic potential using surface electromyography electrodes, using response-triggered averaging, on the triceps of 18 subjects. SETTING: University-affiliated otoneurology clinic. PATIENTS: Eighteen healthy adult volunteers (11 women and 7 men), age ranging between 27 and 36 years. MAIN OUTCOME MEASURES: Latencies and amplitudes of the first two waves of the evoked response. RESULTS: The P1 latency was 36.83 ± 8.42 ms (range, 26.34-57.99 ms; 95% confidence interval [CI], 33.53-40.14 ms), the N1 latency was 43.74 ± 8.80 ms (range, 34.67-66.32 ms; 95% CI, 40.29-47.19 ms), the P1-N1 interlatency was 6.90 ± 1.23 ms (range, 5.21-9.79 ms; 95% CI, 6.42-7.39 ms), and the P1-N1 interamplitude was 93.23 ± 51.25 μV (range, 16.33-206.62 μV; 95% CI, 73.14-113.32 V). CONCLUSION: A monaural sound stimulus elicits a robust and reproducible surface myogenic potential in triceps muscles.