Static and dynamic visual cues in feed-forward postural control

Abstract

Anticipatory postural adjustments (APAs) play an important role in the performance of many activities requiring the maintenance of vertical posture. However, little is known about how variation in the available visual information affects generation of APAs. The purpose of this study was to investigate the role of different visual cues on APAs. Ten healthy young subjects were exposed to external perturbations induced at the shoulder level in standing while the level of visual information about the forthcoming perturbation was varied. The external perturbations were provided by an aluminum pendulum attached to the ceiling. The visual conditions were (1) dynamic cues (full vision and high-frequency strobe light), (2) static cues (low-frequency strobe light) and (3) no cues (eyes open in dark room). Electrical activity of the trunk and leg muscles and center of pressure displacements were recorded and quantified within the time intervals typical for APAs. The results showed that significantly larger APAs were generated in conditions with dynamic visual cues as compared to the conditions with static cues (p < 0.05). Finally, no APAs were observed in the condition where there was complete absence of any visual cues. Principal component analysis further revealed different muscle coupling patterns in the full vision and high-frequency strobe light conditions. These findings suggest the importance of using appropriate visual cues in the generation of APAs.

Does structural leg-length discrepancy affect postural control? Preliminary study

“…It was observed that visual deprivation resulted in a greater sway of the centre of pressure (COP) [ 16 ]. This phenomenon might be explained by the absence of anticipatory postural adjustments (APAs)’ generation without visual inputs [ 17 ]. The ability to control COP position determines correct stability of posture.…”

The effect of aging on anticipatory postural control

“…In the recent past, external perturbations were used to study anticipatory postural control. The studies involving external perturbations such as load catching (Aruin et al 2001; Shiratori and Latash 2001) and pendulum impact paradigms (Santos and Aruin 2008; Santos et al 2010a; Mohapatra and Aruin 2013) revealed that APAs could be seen in preparation to perturbations that were externally induced with no voluntary movement being performed by the subjects themselves. Thus as long as the perturbation is predictable (either external or internal in origin), APAs are observed with patterns that are adequate for counteracting the expected impact.…”

The role of visual feedback in respiratory muscle activation and pulmonary function

“…Vision collects information about the surrounding environment. It constantly provides the central nervous system with information about the location and movement of the body segments, and it helps to maintain balance 10 ) . Thus, measurements were conducted to determine how vision affects the abdominal muscles and whether or not it has any correlation with vital capacity.…”

“…Vision plays an important role in the generation of APAs and increases postural stability 10 ) . When people stand with their eyes closed or have vision problems, postural sway increases by 20–70% 11 ) .…”