THE INFLUENCE OF ACTIVE VERSUS PASSIVE HEAD OSCILLATION, AND MENTAL SET ON THE HUMAN VESTIBULO-OCULAR REFLEX

  • 1 November 1988
    • journal article
    • research article
    • Vol. 59  (11) , 1061-1065
Abstract
We compared passive (manual) whole body,and acitve head oscillation in normal human subjects attempting mentally to influence the vestibule-ocular reflex (VOR). Our objective was to establish simple procedural guidelines for vestibular test procedures in clinical setttings. Using a head-fixed target, both methods of oscillation gain was unity, while passive gain was slightly less than 1. Using an imaged Earth-fixed target in the dark, both active and passive gains were reduced considerably, but passive gain was reduced more. Using an imagined head-fixed target in the dark, VOR gain was near zero at low frequencies but increased as frequency increased. Again, passive gain was less than active gain. At frequencies above 1 Hx, VOR gain in all conditions approached a value between 0.7 and 0.9. We conclude that active and manual passive rotation are simple and effective methods to test the VOR, but emphasize that visual and mental influences must be carefully controlled.