Balance problems with Parkinson's disease: Are they anxiety-dependent?

School of Human Kinetics, The University of British Columbia, Osborne Centre Unit I, 6108 Thunderbird Boulevard, V6T 1Z3, Vancouver, BC, Canada.
Neuroscience (Impact Factor: 3.36). 03/2011; 177:283-91. DOI: 10.1016/j.neuroscience.2010.12.050
Source: PubMed


Non-motor symptoms, such as fear of falling and anxiety, are frequently reported in Parkinson's disease (PD). Recent evidence of anxiety and fear directly influencing balance control in healthy young and older adults, raises the question whether fear of falling and anxiety also directly contribute to the balance deficits observed in PD. The goal of the current study was to examine whether PD patients and controls responded similarly or differently to experimentally induced increases in anxiety. For this purpose, 14 PD patients (tested during a subjective optimal ON state) and 16 healthy age-matched control subjects stood in three conditions of different levels of postural threat: normal threat (quiet standing at ground level); medium threat (standing at the edge of a surface elevated to 80 cm); and high threat (same, but to 160 cm). Outcome measures included mean position, mean power of frequency (MPF) and root mean square (RMS) of centre of pressure (COP) displacements in the anterior-posterior (AP) and medial-lateral (ML) directions. Physiological and psychosocial measures of fear and anxiety were also recorded. Increased threat changed postural control similarly in PD patients and controls; MPF of AP and ML COP increased and the mean COP position was shifted backward in both groups. These results indicate that during the ON state, static balance in PD patients and controls is equally susceptible to the influence of anxiety. Significant correlations observed between COP changes and measures of fear and anxiety provide evidence to support the proposed neural links between structures controlling emotion and postural control. Future studies should further address this issue by including more severely affected patients, by testing the influence of dopaminergic medication, by including more anxious patients, and by using dynamic measures of balance.

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Available from: Elizabeth Pasman, Sep 11, 2015
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    • "However, limited research has investigated how anxiety influences movement control in PD compared with healthy older adults. Studies of both gait and balance did not identify any unique relationship between anxiety and movement behaviors in PD (when compared with healthy controls), but it is important to recognize that participants with PD were only tested in their ON state and these studies excluded participants with PD who experienced high levels of anxiety (Caetano et al., 2009; Pasman et al., 2011). Given that dopaminergic replacement ameliorates basal ganglia-associated deficits , one might expect that testing patients with PD in the OFF state might reveal a different pattern of behavior in response to anxious stimuli. "
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    • "Biological systems generally exploit redundancy to improve robustness and flexibility of control (Karniel, 2011). The exploitation of all available DOFs to maximize performance and flexibility is generally a sign of skill and learning (Bernstein, 1967, page 107–108), whereas the elimination of available DOFs is usually a symptom of declining ability through age (Hsu et al., 2012), disease (Oude Nijhuis et al., 2008; Pasman et al., 2011), or fear (Adkin et al., 2002). "
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