Perceived direction of gravity and the body-axis during static whole body roll-tilt in healthy subjects

Abstract

Objective: We used the subjective visual vertical (SVV) and two different subjective visual body axis (SVBA) methods to quantify roll-tilt perception under gravity, and investigated the characteristics of these methods during static roll-tilt. In addition, we independently developed a compact device to facilitate evaluation of SVBA in different gravitational environments.Methods: Ten male volunteers participated in this study. We created a roll-tilt environment using a flight simulator in a dark room. The cockpit of the simulator was tilted leftward or rightward (−30°, −20°, −10°, 0°, 10°, 20° and 30°) in each randomly ordered trial. We quantified roll-tilt perception such that the experiment was conducted under 21 different conditions per participant.Results: We found no significant differences among the SVV error and the two types of SVBA error.Conclusions: The SVV and the SVBA methods may be useful for evaluating subjective roll-tilt perception.