Postural Sway and the Frequency of Horizontal Eye Movements

In two experiments, participants were asked to shift gaze to follow horizontal target oscillation to allow us to investigate relations between eye movements and postural dynamics. Postural sway variability was reduced during target oscillation when compared to sway while viewing a stationary target. The infl uence of target oscillation on sway was independent of target oscillation frequency. Similar results were obtained with measurements of the center of pressure (Experiment 1) and the displacement of body segments (Experiment 2). The overall results are not consistent with the view that eye movements and postural control compete for limited central processing resources. The results are consistent with the thesis of a functional integration of postural control with visual performance. Key Words: sway, stance, perception, gaze, visual performance Recent research provides ample evidence of interactions between supra-postural activity and the control of stance (Woollacott & Shumway-Cook, 2002). Supra-postural tasks are super-ordinate to the maintenance of posture (Stoffregen, Adolph, Gorday & Sheng, 1997). Many studies have shown that postural contro