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.

Chinese abstract

目的：我们使用主观视觉垂直（SVV）和两种不同的主观视觉体轴（SVBA）方法对重力下的滚动-倾斜感知进行量化, 并在静态滚-倾过程中研究了这些方法的特点。 此外, 我们还独立开发了一种精致设备, 便于在不同重力环境中对SVBA进行评估。

方法：10名男性志愿者参加了本项研究。 我们在黑暗的房间里使用飞行模拟器创建了一个滚动-倾斜环境。 在每个随机试验中, 模拟器的驾驶舱向左或向右（-30°、-20°、-10°、0°、10°、20°和30°）倾斜。 我们对倾斜感知进行量化, 每个参与者的实验都在21个不同的条件下进行。

结果：我们发现SVV误差与两种类型的SVBA误差之间并没有显著性差异。

结论：SVV和SVBA方法对评估主观倾斜感知可能都有用。

Keywords:

• Subjective visual vertical
• subjective visual body axis
• roll-tilt
• gravity
• space

Acknowledgments

We thank Dr Makoto Igarashi for comments regarding our experiment. We thank the Aeromedical Laboratory, the Japan Air Self-Defense Force and the Jupitor Corporation for help with the operation of the GYROLAB GL-4000. We also thank Dr Risa Tamura (Department of Rehabilitation, Self-Defense Forces Central Hospital, Tokyo, Japan) for advice on statistical analysis and discussion. This research was supported by grants from JSPS Kakenhi (20500582) and ‘Ground-based Research Announcement for Space Utilization’ promoted by the Japan Space Forum.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Additional information

Funding

This research was supported by grants from JSPS Kakenhi (20500582) and ‘Ground-based Research Announcement for Space Utilization’ promoted by the Japan Space Forum.