| Abstract No.: | A-C1097 |
| Country: | Canada |
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| Title: | UNDERSTANDING THE MOVEMENT PATTERNS OF PEAK-DOSE LEVODOPA-INDUCED DYSKINESIA IN PATIENTS WITH PARKINSON'S DISEASE |
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| Authors/Affiliations: | 2 Christian Duval*; 2 Jean-Francois Daneault; 3 Roderick Edwards; 3 Rena Mann; 3 Julie Zhou; 1 Mandar Jog;
1 Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada; 2 Département de Kinanthropologie, Université du Québec à Montréal, QC, Canada; 3 Dept. of Mathematics & Statistics, University of Victoria, BC, Canada
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| Content: | Objectives: We have recently demonstrated that the amplitude and body location (motor topography) of peak-dose levodopa-induced dyskinesia (LID) in patients with Parkinson’s disease (PD) varies greatly over short periods of time (i.e., seconds). We also found that LID are not random, but possess some dynamical structure in their movement patterns. In this study, we measured coherency between various body segments during standing to address the question of whether LID arise from the unwanted release of a single motor output or whether they are driven by multiple uncorrelated neural signals.
Materials and Methods: Ten control subjects were tested, as well as twenty patients with idiopathic PD, ten of whom had clear LID, while the other ten patients did not. A magnetic tracker system was used to provide 3D positions over a 60-second period of 15 sensors placed on key body segments while subjects maintained a standing position with arms extended in front of them. Coordination in the kinematics of pairs of body segments was assessed by spectral analysis. For each pair examined, we calculated the highest coherency between 0.5 and 3.0 Hz and the frequency at which this maximum coherency occurred.
Results: Analysis of variance showed that, in the majority of the comparisons we studied, the control group had the highest coherency and the patients with LID had the lowest. The patients with LID also tended to have their maximum coherency at higher frequencies than non-dyskinetic patients and controls. These trends appeared in all types of inter-segment comparisons, including bilaterally symmetric segments, biomechanically linked segments (in which coherencies were higher overall in all groups, but still different between groups) and in other comparisons.
Discussion: These results suggest that LID is the consequence of different neural outputs driving different limbs in an uncoordinated manner. These movements are superimposed on an otherwise more coherent and lower frequency pattern of kinematics, which might reflect postural sway. The clinical implications of these findings is that patients may have to take into consideration the release of these incoherent neural outputs, and attempt to integrate them into a coherent motor output when producing voluntary movements. The ensuing increase in cognitive effort is surely responsible for some of the difficulties in motor behaviours seen in these patients. |
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