The interaction of visual, vestibular, proprioceptive and auditory stimuli in the maintenance and control of postural sway behaviour

The individual and interactive effects of visual, vestibular, neck proprioceptive and auditory input on postural sway behaviour were examined in 80 healthy subjects (35 females, 45 males) aged 18 and 43 years old. The effects of static visual, vestibular and neck proprioceptor stimulation, both without and with auditory stimulation, as well as the effects of dynamic vestibular and neck proprioceptor stimulation, again without and with auditory stimulation, were examined. Comparisons were also made between static and dynamic vestibular and neck proprioceptor stimulation. In addition, the effect of gender on postural behaviour was also investigated.
The results show that visual feedback acts as a stabilising influence, whereas vestibular and neck proprioceptor stimulation, either static or dynamic, as well as auditory feedback have both a stabilising and a destabilising effect. Static vestibular stimulation improves postural stability more than dynamic stimulation. Static neck proprioceptive input and static vestibular-neck proprioceptor interaction leads to an increase in mediolateral and anteroposterior sway magnitudes, while dynamic input for both leads to anteroposterior stability. The visual-vestibular interaction influence on posture depends on the extent of the visual and vestibular agreement. The visual-neck proprioceptor interaction destabilises posture, as does the visual-auditory interaction. Static vestibular- auditory interaction improves anteroposterior stability, whereas the dynamic interaction leads to mediolateral and anteroposterior destabilisation. The neck proprioceptor-auditory interaction improves anteroposterior stability, but increases mediolateral instability. The visual-vestibular-neck proprioceptor, as well as visual-neck proprioceptor-auditory, interaction stabilises anteroposterior posture, whereas the visual-vestibular-auditory interaction destabilises mediolateral control. The vestibular-neck proprioceptor-auditory interaction with static vestibular and neck proprioceptive input causes postural stability, whereas dynamic stimulation leads to either postural stabilisation or destabilisation. Finally, the visual-vestibular-neck proprioceptor-auditory interaction appears to control the direction of movement. There appears to be a sex difference in postural maintenance due to the dominant role of the different sensory inputs in each gender.
It is concluded that the individual and interactive effects of visual, vestibular, neck proprioceptive and auditory inputs all influence postural maintenance. Pathways in the central nervous system for postural control are proposed, some of which are already known, while others are proposed on the basis of the findings presented in this study. The proposed pathways require further elucidation and investigation.