Figure 5

Orientation decomposition of the CoP trajectory of a representative individual with Parkinson’s disease on medication maintaining an upright balance on an unstable surface with eyes closed. (a) CoP along the anatomical AP and ML axes. (b) \(\theta \)-dependent heterogeneity in CoP fluctuations, indicated by the angle dependence of \(\log _{10}^{(\theta )}F^{(\theta )}(\tilde{s})\) vs. \(\log _{10}\tilde{s}\), where \(\tilde{s}\sim s/1.93\) in the second order DDMA. (c) \(\theta \)-dependence of the local slopes of \(\log _{10}^{(\theta )}F^{(\theta )}(\tilde{s})\) vs. \(\log _{10}\tilde{s}\), indicating the spatial distribution of temporal correlations. (d) \(\theta \)-dependence of the slope in the range of \(1.2<\log _{10}{\tilde{s}}<2.5\). (e) Reconstructed CoP along the original directions of postural control, \(\hat{\epsilon }_{1}[i],\hat{\epsilon }_{2}[i]\). (f) Fluctuation functions of CoP along the original directions of postural control, \(\hat{\epsilon }_{1}\) with \(\hat{\theta }_{1}=52^{\circ }\) and \(\hat{\epsilon }_{2}\) with \(\hat{\theta }_{2}=113^{\circ }\).