Detection and reference value of cervical and ocular vestibular evoked myogenic potential in military pilots

Objective To obtain the detection method and reference constants of cervical vestibular evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential (oVEMP) in military pilots and to provide reference basis for evaluating pilot's otolith function in aeromedical assessment. Methods Thirty-three (66 ears) healthy male active duty fighter pilots were selected as study subjects. They were between the age of 25 to 42 years old (30.3±4.8 years). cVEMP and oVEMP were induced unilaterally by means of 500 Hz air-conducted tone burst stimulation. The VEMPs threshold of each ear was examined and the reference range of amplitude, latency and wave interval were calculated. Results The composite wave of cVEMP and oVEMP was observed in 33 pilots. The evoked rate was 100%. The latency of p13 and n23, p13-n23 interval, peak-to-peak p13-n23 amplitude and asymmetry ratio of cVEMP in these pilots were (13.94±1.59)ms, (20.95±1.59)ms, (7.01±1.34)ms, (224.70±66.15)μV, (0.11±0.10). The amplitude had slight difference between the ears while the cVEMP p13 latency, n23 latency and wave interval showed very small difference between the ears. The latency of N1 and P1, N1-P1 interval, peak-to-peak N1-P1 amplitude and asymmetry ratio of oVEMP in the pilots was (11.1±0.99)ms, (15.41±0.85)ms, (4.31±0.84)ms, (2.23±0.59)μV, (0.10±0.08) respectively. The amplitude of oVEMP, latency of N1, latency and wave interval of P1 showed unobvious difference between left and right ears. Conclusions This study has established the conventional detection methods and constants of cVEMP and oVEMP of military pilots and these provide the objective reference to evaluate the functions of utricle and sacculus in aeromedical assessment. Key words: Vestibular function tests; Evoked potentials; Saccule and utricle; Pilot