Effects of a sound source moving in a vertical plane on postural responses in humans.

The effects of moving sound sources on postural responses were studied. Sound source movement was simulated by sequential switching of loudspeakers located along an arch positioned in the sagittal plane relative to the subject. The total durations of the sound stimulus movement were 1.6, 3.2, and 4.8 sec. Signals of 1.6 and 3.2 sec led to decreases in the mean amplitude of oscillogram oscillations in the sagittal and frontal planes. Stabilogram curves averaged for all subjects for the signal of duration 4.8 sec showed that the center of gravity deviated during exposure to the sound stimulus towards the side opposite the direction of movement of the sound source.