Self-motion perception: assessment by real-time computer-generated animation

We report a new procedure for assessing complex self-motion perception. In three experiments, subjects manipulated a 6 degree-of-freedom magnetic-fiel d tracker which controlled the motion of a virtual avatar so that its motio n corresponded to the subjects' perceived self-motion The real-time animati on created by this procedure was stored using a virtual video recorder for subsequent analysis. Combined real and illusory self-motion and vestibulo-o cular reflex eye movements were evoked by cross-coupled angular acceleratio ns produced by roll and pitch head movements during passive yaw rotation in a chair. Contrary to previous reports, illusory self-motion did not corres pond to expectations based on semicircular canal stimulation. Illusory pitc h head-motion directions were as predicted for only 37% of trials; whereas, slow-phase eye movements were in the predicted direction for 98% of the tr ials. The real-time computer-generated animations procedure permits use of naive, untrained subjects who lack a vocabulary for reporting motion percep tion and is applicable to basic self-motion perception studies, evaluation of motion simulators, assessment of balance disorders and so on. (C) 2001 E lsevier Science Ltd. All rights reserved.