Deterministic center of pressure patterns characterize postural instability in Parkinson’s disease

Abstract

Static posturographic recordings were obtained from six Parkinson's patients and six age-matched, healthy control participants. The availability of vision and visuo-spatial cognitive load were manipulated. Postural sway patterns were analyzed using recurrence quantification analysis (RQA), which revealed differences in center of pressure (COP) dynamics between Parkinson's and control participants. AP COP trajectories for the Parkinson's group were not only significantly more variable than for the control group, but also exhibited distinct patterns of temporal dynamics. The visual manipulation did not differentially affect the two groups. No cognitive load effects were found. The results are generally consistent with the hypothesis that pathological physiological systems exhibit a tendency for less flexible, more deterministic dynamic patterns.

The Influence of a Cognitive Task on the Postural Phase of Gait Initiation in Parkinson’s Disease: An Electromyographic-Based Analysis

“…The size of the sample used in this study is in-line with other studies of this kind, such as the ones of Nocera et al (2013), with 13 individuals with PD; Rogers et al (2011), with 8 individuals with PD; and Schmit et al (2005) with 6 individuals with PD. However, the sample size and consequent small statistical power is a limitation of this study; thus it should be seen as an exploratory study.…”

Cluster Analysis of Center-of-Pressure Measures

“…Measurements of postural stability are used to identify neuromuscular diseases (Schmit et al, 2006) and to assess the risk of falls in frail populations (Jbabdi, Boissy, & Hamel, 2008). Studies have also shown that people with neuromuscular disorder (e.g., polio survivors) demonstrate a higher frequency of falls, frequently resulting in injury and subsequent fear of falling (Bickerstaffe, Beelen, and Nollet 2010).…”

Dynamic Patterns of Postural Fluctuations During Quiet Standing: A Recurrence Quantification Approach

“…RQA can extract a system's dynamics by quantifying the system's repeatability through several variables. It is shown that RQA is sensitive to changes in postural sway dynamics in response to variations in availability of sensory information used to control balance and optical flow [Riley et al 1999], to balance expertise [Schmit et al 2005], to balance impairments [Schmit et al 2006],and also embedding parameters [Hasson et al 2007]. …”