Velocity control in Parkinson's disease: a quantitative analysis of isochrony in scribbling movements

Article Article scientifique Article Velocity control in Parkinson's disease: a quantitative analysis of isochrony in scribbling movements eng 2009 author Viviani Paolo 26547 author Burkhard Pierre 0000-0002-7459-5778 92389 author Chiuve Sabina Catalano author Corradi Dell'Acqua Corrado 708925 author Vindras Philippe 29223 259-283 10.1007/s00221-008-1695-z 19153724 0014-4819 http://www.springerlink.com/content/p10n373262747215/fulltext.pdf An experiment was conducted to contrast the motor performance of three groups (N = 20) of participants: (1) patients with confirmed Parkinson Disease (PD) diagnose; (2) age-matched controls; (3) young adults. The task consisted of scribbling freely for 10 s within circular frames of different sizes. Comparison among groups focused on the relation between the figural elements of the trace (overall size and trace length) and the velocity of the drawing movements. Results were analysed within the framework of previous work on normal individuals showing that instantaneous velocity of drawing movements depends jointly on trace curvature (Two-thirds Power Law) and trace extent (Isochrony principle). The motor behaviour of PD patients exhibited all classical symptoms of the disease (reduced average velocity, reduced fluency, micrographia). At a coarse level of analysis both isochrony and the dependence of velocity on curvature, which are supposed to reflect cortical mechanisms, were spared in PD patients. Instead, significant differences with respects to the control groups emerged from an in-depth analysis of the velocity control suggesting that patients did not scale average velocity as effectively as controls. We factored out velocity control by distinguishing the influence of the broad context in which movement is planned--i.e. the size of the limiting frames--from the influence of the local context--i.e. the linear extent of the unit of motor action being executed. The balance between the two factors was found to be distinctively different in PD patients and controls. This difference is discussed in the light of current theorizing on the role of cortical and sub-cortical mechanisms in the aetiology of PD. We argue that the results are congruent with the notion that cortical mechanisms are responsible for generating a parametric template of the desired movement and the BG specify the actual spatio-temporal parameters through a multiplicative gain factor acting on both size and velocity. Aged Aged, 80 and over Algorithms Analysis of Variance Female Hand Humans Male Middle Aged Motion Movement/*physiology Parkinson Disease/*physiopathology *Psychomotor Performance Regression Analysis Dewey 616.8 Open Access - Licence nationale Springer 61 Département des neurosciences cliniques 226 false 124 Groupe Pierre Burkhard (neurologie) 154 Experimental brain research 194 2 47ef4f7c-aec4-4b43-832f-8b20092f965a Article (Published version) Public file1.pdf 744269 application/pdf openAccess Faculté de médecine / Section de médecine clinique / Département des neurosciences cliniques

Title	Published in	Year	Views	Downloads

Velocity control in Parkinson's disease: a quantitative analysis of isochrony in scribbling movements	Experimental brain research	2009	622	496
Planning short pointing sequences	Experimental Brain Research	2005	338	268

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Vindras, Philippe