Evaluation of the function was carried out by using unilateral caloric test in different arousal status. The goal of this investigation is to further investigate the normal parameters of vestibular function. Maximum speed, latency, frequency, medium speed and number of beats of the slow component of nystagmus were calculated, as well as, the morphological pattern of the standard outline. Voluntary suppression of vestibular response was tested. A test request method was proposed as the best way to fix attention of subjects.