Ocular Vestibular-Evoked Myogenic Potentials in Healthy Pilots and Student Pilots

XIE S-J, XU Y, Bi H-Z, JIA H-B, ZFIENG Y-J, ZFIANG Y-G. Ocular vestibular-evoked myogenic potentials in healthy pilots and student pilots. Aviat Space Environ Med 2011; 82:729-33. Introduction: Excellent vestibular function (including utricular function) is important for pilots to maintain correct spatial orientation during flight. Vestibular-evoked myogenic potential (VEMP) recorded from extraocular muscles, the so-called ocular VEMP (oVEMP), can be used to evaluate utricular function. However, oVEMP has not been applied to pilots because of lack of reliable normative data. Hence, this study is designed to establish preliminary normative data for oVEMP induced by air-conducted sound in pilots and student pilots. Methods: There were 62 healthy student pilots (30 male and 32 age-matched female) and 31 healthy male fighter pilots who were recruited as study participants. During binaural air-conducted sound stimulation oVEMP was recorded bilaterally. The latencies of nl and pl, nl-pl interval, peak-to-peak nl-pl amplitude, and asymmetry ratio (AR) of oVEMP in all participants were collected. Meanwhile, the effects of gender and age on oVEMP were also investigated. Results: The latencies of n1 and pl, nl-pl interval, nl-pl interpeak amplitude, and AR of oVEMP in all participants were 10.35 +/- 0.66 ms, 15.18 +/- 1.07 ms, 4.75 +/- 0.99 ms, 6.75 +/- 4.13 mu V, and 13.22 +/- 9.13%, respectively. No significant difference existed between male student pilots and male pilots in terms of oVEMP parameters. The only significant difference was the nl pl amplitude between age-matched male and female student pilots: 6.96 +/- 3.85 mu V for male student pilots and 5.47 +/- 3.10 mu V for female student pilots. Conclusions: oVEMP should be interpreted with the AR rather than raw amplitude itself. Each institution should determine its own normal values.