title: 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.
authors.affiliation: Department of Psychology, University of Cincinnati, ML 0376, Cincinnati, OH 45221-0376, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Schmit
authors.forename: Michael A
authors.initials: MA
authors.lastname: Riley
authors.forename: Arif
authors.initials: A
authors.lastname: Dalvi
authors.forename: Alok
authors.initials: A
authors.lastname: Sahay
authors.forename: Paula K
authors.initials: PK
authors.lastname: Shear
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Shockley
authors.forename: Raymund Y K
authors.initials: RY
authors.lastname: Pun
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017711:Nonlinear Dynamics; D010300:Parkinson Disease / Q000503:physiopathology*; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011312:Pressure; D011930:Reaction Time / Q000502:physiology; D012677:Sensation / Q000502:physiology*; D013997:Time Factors