Kim TH, et al. - The physicians performed this study to identify the difference of gain value in the video head impulse test (vHIT) according to the age of the patient and the direction of the impulse. They reported that the vestibulo-ocular reflex (VOR) gain declines with increasing age, over 70 years on the horizontal canal, and over 80 years on the vertical canal. In addition, horizontal VOR gain of rightward impulse was higher as compared with the leftward impulse in right-eye recordings only. However, according to the direction of impulse, the vertical canal displayed no difference of gain.