Comparative study on the reference value of vestibular autorotation test between military pilots and ordinary personnel

Objective To compare the various parameters of vestibular autorotation test (VAT) between the Chinese military pilots and ordinary personnel. Methods Thirty-four pilots who had passed the physical examination, including the caloric test and video-head impulse test of vestibular functions, were selected as subjects. They received vestibular autorotation test by VAT98-3 detector that manufactured by the WSR Company of United States. The frequencies, horizontal and vertical gains and phase shift of the vestibular ocular reflex (VOR) in VAT were analyzed and compared with the corresponding parameters of 100 ordinary personnel stored in the detector. Results By comparing the measured values of 34 military pilots with 100 ordinary personnel the significant differences were found on the horizontal gain at 2.0, 2.3, 4.7, 5.1, 5.5, 5.9 Hz, the horizontal phase shift at 2.0, 3.9, 4.7, 5.1 Hz, the vertical gain at 5.5, 5.9 Hz and the vertical phase shift at 2.0, 3.9, 5.1 Hz (t=2.106-18.647, P<0.05). The vertical phase shifts on the frequencies of 2.3, 2.7, 3.1, 3.5, 4.3 Hz and the asymmetry showed insignificant difference as compared with the reference values of ordinary personnel. Conclusions The military pilots show higher gains on the 2.0 and 2.3 Hz VAT than the ordinary personnel and the gain is close to 1, but on 4.7, 5.1, 5.5, and 5.9 Hz. The differences should be considered in the evaluation of vestibular functions for military pilots. The aeromedical assessment should take the norm of military pilot as the reference. Key words: Vestibular function tests; Eligibility determination; Reference values; Pilots