New Insights on Emotional Contributions to Human Postural Control

Abstract

It has been just over 20 years since the effects of height-induced threat on human postural control were first investigated. Raising the height of the support surface on which individuals stood increased the perceived consequences of instability and generated postural control changes. Since this initial work, converging evidence has accumulated supporting the efficacy of using height-induced threat to study the effects of emotions on postural control and confirming a direct influence of threat-related changes in arousal, anxiety, and fear of falling on all aspects of postural control, including standing, anticipatory, and reactive balance. In general, threat-related postural changes promote a greater physical safety margin while maintaining upright stance. We use the static balance literature to critically examine the current state of knowledge regarding: (1) the extent to which threat-related changes in postural control are sensitive to threat-related changes in emotions; (2) the underlying neurophysiological and cognitive mechanisms that may contribute to explaining the relationship between emotions and postural control; and (3) the generalizability of threat-related changes across different populations and types of threat. These findings have important implications for understanding the neuromechanisms that control healthy balance, and highlight the need to recognize the potential contributions of psychological and physiological factors to balance deficits associated with age or pathology. We conclude with a discussion of the practical significance of this research, its impact on improving diagnosis and treatment of postural control deficits, and potential directions for future research.

Keywords: anxiety; balance; emotions; fear; postural control; surface height; threat.

Figure 1

Threat context (A) and adaptation (B) effects. (A) Change in center of pressure (COP) mean position (MP), mean power frequency (MPF), and root mean square (RMS) between threat and no threat conditions for height, [0.8 and 3.2 m surface; 60-s stance duration; modified from (34)] and support surface translations (Trans) in the anterior-posterior (AP) direction [30 s stance duration; modified from (75)] and medial-lateral (ML) direction [60-s stance duration; (76)]. Closed circles reflect AP COP measures while open circles reflect ML COP measures. (B) Adaptation of emotional, cognitive (attention focus to movement processes; Att. MP) and postural responses for low (gray circles) and high (black circles) surface heights over 5 repeated 120-s standing trials (77).