Functional relation between postural sway and saccadic eye movements is strong and not altered by moving visual environment and concomitant memory task

We investigated whether the adaptation of postural control to perform saccadic tasks is still maintained in challenging situations such as when the posture is challenged with a large movement of the moving room and with the addition of a second perturbation as a visual task of memorization. Thirty young adults (20.0 ± 1.3 years) were randomly assigned to the control and experimental groups. Participants stood upright on a force plate inside a moving room wearing eye-tracking. The room moved back and forth (anterior–posterior direction), at low (.6 cm—first and third trials) and high (3.5 cm—second trial) amplitude, and frequency of .2 Hz. In each trial, participants performed left-right horizontal saccades on a target (1.1 Hz). The experimental group also performed a concomitant number memorization task. There were no differences between groups in the coupling between center of pressure (CoP) displacements and visual stimulus in any condition. There was also no difference in the performance of the saccadic task. In the memorization task, CoP displacements in response to the visual stimulus frequency (room motion) were not affected. The performance in the memorization task was similar between room conditions. Overall, increasing cognitive involvement by adding a working memory task does not deteriorate the postural stabilization of young adults to accomplish accurate gaze shifts. Also, it does not interfere with adaptive visual reweighting due to changes in the moving room amplitude. In conclusion, young adults are flexible in optimizing their postural control to succeed in multiple tasks even under perturbation.