Effect of visually induced self-motion perception (vection) on upright standing posture
Masumi Ichikawa, Satoru Watanabe, 真澄 市川, 悟 渡邉 · Institutional Repositories DataBase (IRDB) · 1992
This study examined the relationship between the magnitude of vection (visually induced perception of self-motion) and the forward body tilt induced by optokinetic stimulation (OKS). Twelve healthy adult subjects participated in this study. A moving random dot pattern as an OKS was projected on a large hemispherica1 dome screen placed in front of the subject. The pattern was moved downward on the screen. Each subject stood on a force-measuring platform in Romberg's position and gazed at a red fixation point in the center of the screen. OKS velocity in a range of 10 to 100 deg/sec was presented in random order. The magnitude of pitch vection caused by OKS was measured by the ten-point assessment method. The body sway values registered by the force-measuring platform were stored on a data recorder. After the antero-posterior component of body sway was converted by 12 bit A/D converter, a maximum point and average level of forward displacement of center of gravity caused by OKS was calculated by computer. Power spectrum analysis was applied for anterio-posterior body sway by the FFT method. From these analyses it was concluded that there was a close relationship between the magnitude of vection and the forward displacement of center of gravity caused by OKS. This suggests that the vection induced by moving patterns strongly modifies readjustment of the upright standing posture.