The role of visual cues in the acquisition and transfer of a voluntary postural sway task

We investigated the acquisition and transfer of a visually guided voluntary postural sway (PS) task that was practiced with the provision of either continuous or end point visual cues. Forty healthy adults were randomly assigned in to one of the four groups that practiced sway using different combinations of target and performance feedback. Participants were asked to voluntarily sway in the sagittal plane at a pre-set frequency (0.23 Hz) by matching the force exerted on a dual force platform to a visual target. Baseline, post-test, transfer and retention (24h later) tests required performance of the PS task paced by a metronome. Continuous target cues resulted in greater accuracy at the peaks but at the cost of increasing movement intermittency. End-point cues on the other hand, produced more stable sway patterns but target overshooting. These adaptations differently generalized in the auditory-driven workspace, as reflected by more stable sway patterns for the groups practicing with end target cues and an enhancement of the ankle stiffening strategy for the groups practicing with continuous targets. It is suggested that the types of visual cues available during visually driven PS have a strong influence not only on the acquisition of this task but also on its generalization to the audio-motor workspace.