Destabilization of Human Vertical Posture by Affective Auditory Stimuli

Abstract: Maintaining a stable upright posture is a complex physiological process. Destabilizing this posture is one of the tools to study the mechanisms of upright postural regulation. Sound stimulation allows us to effect posture in both the sagittal and frontal planes of the body. The aim of this work was to evaluate postural modulation in response to listening affective audio signals from one of four directions in space. In healthy subjects (n = 33), postural parameters were recorded in silence and with sound stimulation. The sound stimulation was of three types: long signals without pauses, long signals with pauses, and short signals with pauses. The sound sources were in front, behind, right, or left. The duration of stimulation and postural analysis was 30 s. There was an increase in postural parameters in response to affective sounds, which supports their destabilizing effect on posture. Comparison of the effects of three types of stimulation on posture showed that as the total duration of auditory stimuli during posture registration decreased the number of sound source positions at which significant changes in postural parameters were obtained decreased. Regardless of the type of stimulation, significant increases in postural parameters were found in all three cases when the sound source was located on the right side of the body. When the sound source was located in the sagittal plane (in front and behind), the effect was mainly observed for long duration sound signals, but it was less pronounced than for stimulation on the right side. No significant changes in postural parameters were found when stimulation was performed on the left side.