The investigators used the same parameters of stimulation and analysis described in cVEMP. Non inverting electrodes were placed on the face just inferior to each eye (inferior oblique muscle), reference electrode was placed 1-2cm below contralateral to the stimulus and ground electrode in the forehead. The subject was placed in the sitting position and instructed to look upward. The latencies of initial negative (nI) and positive (pI) peak were measured. They considered normal nI latencies from 10.2 to 11.8 and from 14.7 to17.3 pI.