Relationship between Attention and Effect of Gaze or Auditory Stimulation on Directions of Postural Sway

－Investigation Using Postural Response Induced by Neck Dorsal Muscle Stimulation－

Abstract

The direction of postural sway in response to neck dorsal muscle stimulation can be influenced by change in gaze direction or direction of auditory stimulation. A previous study has reported that the sway directions by gaze change and auditory stimulation are correlated and that the degree of influence differs from the left to right side. However, mechanisms for the correlated response and lateral difference remain largely unknown. Aiming at uncovering the mechanisms, this study further investigated the postural responses by the gaze change and auditory stimulation with more subjects. In addition, attention by auditory stimulation was investigated using line-motion illusion because we hypothesized that the mechanisms are related to the direction of attention. Fifty-two subjects participated in the following measurements: We measured the sway direction during gaze change to the left or right and auditory stimulation from the left or right. The correlation coefficients between the measured directions were significant on both sides. In 24 out of the 52 subjects, the line-motion illusion with a preceding auditory stimulation was observed frequently. The results suggest that the auditory stimulation can also cause attention, implying that postural sway occurs in the direction of attention attracted by the gaze or auditory stimulation.