Consciously processing balance leads to distorted perceptions of instability in older adults

Abstract

Background Persistent dizziness without a clear cause is common in older adults. We explored whether an anxiety-driven preoccupation with consciously processing balance may underpin the distorted perceptions of unsteadiness that characterises ‘unexplained’ dizziness in older adults. Methods We experimentally induced anxiety about losing one’s balance (through a postural threat manipulation) in a cohort of asymptomatic older adults and evaluated associated changes in perceived stability, conscious movement processing and postural control. These outcomes were also assessed when performing a distracting cognitive task designed to prevent anxiety-related conscious movement processing, in addition to during baseline conditions (ground level). Results Despite a lack of increase in postural sway amplitude (p = 0.316), participants reported reductions in perceived stability during postural threat compared to baseline (p < 0.001). A multiple linear regression revealed that anxiety-related conscious movement processing independently predicted perceptions of instability during this condition (p = 0.006). These changes were accompanied by alterations in postural control previously associated with functional dizziness, namely high-frequency postural sway and disrupted interaction between open- and closed-loop postural control (ps < 0.014). While the distraction task successfully reduced conscious processing (p = 0.012), leading to greater perceived stability (p = 0.010), further increases in both postural sway frequency (p = 0.002) and dominance of closed-loop control (p = 0.029) were observed. Conclusion These findings implicate the role of conscious movement processing in the formation of distorted perceptions of unsteadiness, suggesting that such perceptions may be modifiable by reducing an over-reliance on conscious processes to regulate balance.

A comparison of placebo and nocebo effects on objective and subjective postural stability: a double-edged sword?

“…Participants who expected that they would perform poorly perceived themselves to be more unstable than those who expected that they would perform well-irrespective of actual performance (i.e., objective postural stability). Given that numerous clinical balance disorders are characterized by distorted perceptions of instability [whereby actual and perceived stability are decoupled (Ellmers et al, 2021)], these novel findings have high levels of applied relevance. Future work should explore if such distortions of perceived instability can be altered through targeting faulty expectancies about balance performance.…”

Factors associated with dynamic balance in people with Persistent Postural Perceptual Dizziness (PPPD): a cross-sectional study using a virtual-reality Four Square Step Test

“…The FSST-VR is a complex balance task, requiring increased awareness of body location and orientation, as well as planning complex directional changes. It has been shown that when facing an anxiety-inducing postural threat, high attention to selfmovement predicts subjective perception of instability in healthy older individuals under normal visual conditions [43]. It may be that people with PPPD and high trait anxiety, when faced with high visual loads, are worried of losing their balance, therefore freeze degrees of freedom and as a result limit spatial ROM during the task.…”

Responses to balance challenges in persons with panic disorder: A pilot study of computerized static and dynamic balance measurements

“…In this regard, of relevance is a recent study that has found that experimentally‐induced anxiety leads to distorted perceptions of subjective instability (Ellmers et al., 2021), which may lead us back to adopting over all "rigid" postural behavior.…”