HUMAN POSTURAL RESPONSES TO LEG MUSCLE VIBRATION ALTERED BY VISUAL SCENE MOTION

Sensory interaction in posture control was investigated by postural responses to differently timed proprioceptive and visual stimulation. The aim of this study was to find out whether visual scene motion started some seconds before proprioceptive stimulation onset can modulate magnitude and velocity of the postural responses to the lower leg muscle vibration. We evaluated postural responses of 22 subjects (10 men and 12 woman, range 24-60 years) to paired proprioceptive-visual stimulation with difference in the timing of the both stimulation onsets. As proprioceptive stimulation was used both soleus muscles vibration with duration 8 s, frequency 55 Hz and amplitude 1 mm. Visual stimulation was rotating disc in diameter 125 cm, placed on the right side of subjects and moving in both direction. The visual stimulation started either together with the vibration, or there was 3 s before vibration onset. Centre of pressure (CoP) was recorded by force platform. Trunk tilts in AP direction was measured by tw