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

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.