Movement Smoothness Differentiates Voluntary from Parkinsonian Bradykinesia | OMICS International | Abstract
ISSN: 2155-6105

Journal of Addiction Research & Therapy
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Research Article

Movement Smoothness Differentiates Voluntary from Parkinsonian Bradykinesia

Nicolas Bayle1,2,6*, Stephen J Fried3, Elisabeth A Kappos4,7, Emilie Hutin1,2, Karen Fung5, Donald J Weisz5 and Jean-Michel Gracies1,2

1Laboratoire Analyse et Restauration du Mouvement, Université Paris Est Créteil, Créteil, France

2Service de Rééducation Neurolocomotrice, Unité de Neurorééducation, Hôpitaux Universitaires Henri Mondor, Créteil, France

3Physiologic Assessment Services, Teaneck, New Jersey, USA

4Department of Neurology, Mount Sinai Medical Centre, New York, USA

5Department of Neurosurgery, Mount Sinai Medical Centre, New York, USA

6Neuroscience Research Australia and University of New South Wales, Sydney, Australia

7Department of Plastic Hand Surgery, University Hospital Basel, Switzerland

Corresponding Author:
Nicolas Bayle
Service de Rééducation Neurolocomotrice AP-HP
Hôpitaux Universitaires Henri Mondor
51 Avenue du Maréchal de Lattre de
Tassigny 94000 Créteil, France
Tel: +331 49 81 49 42
Fax: +331 49 81 24 84
E-mail: [email protected]

Received date: date: Nov 17, 2015; Accepted date: date: Jan 25, 2016; Published date: date: Jan 31, 2016

Citation: Bayle N, Fried SJ, Kappos EA, Hutin E, Fung K, et al. (2016) Movement Smoothness Differentiates Voluntary from Parkinsonian Bradykinesia . J Addict Res Ther 7:264. doi:10.4172/2155-6105.1000264

Copyright: © 2016 Bayle N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.



Objective: While considered a key symptom, bradykinesia is not specific to Parkinson's disease (PD). Measuring movement smoothness may help distinguish PD-induced from volitional bradykinesia.
Methods: Eight PD patients and 12 healthy subjects performed alternating, maximal speed, small and large elbow flexion-extension movements. Six of the healthy subjects also performed the task while matching the average speed of PD patients. From angular displacement, we derived speed, acceleration, jerk measures and the power spectrum of acceleration frequencies. Acceleration variability was evaluated using the Normalized Average Rectified Jerk (NARJ) and the fast-frequency to movement-frequency (FF/MF) ratio. Ratios of maximal velocities and accelerations in large to those in small movements (L/S velocity and acceleration ratios) were also measured.
Results: NARJ in PD was 189 ± 17% of controls and 151 ± 14% of speed-matched controls (p=0.004; pairwise p=0.003, p=0.051 respectively) in large movements and 146 ± 11% of controls and 139 ± 11% of speed-matched controls (p=0.012; pairwise p=0.011, p=0.067 respectively) in small movements. FF/MF ratio in PD was 277 ± 45% of controls and 200 ± 32% of speed-matched controls (p=0.032; pairwise p=0.028, non-significant, respectively) in large movements and 613 ± 73% of controls and 246 ± 29% of speed-matched controls (p<0.001; pairwise p<0.001, p<0.001 respectively) in small movements. Time since diagnosis, but not age, was correlated with NARJ (p<0.05) and FF/MF ratio (p<0.01) for all movements. L/S ratios did not differentiate PD from speed-matched movements in the study sample.
Conclusion: The two smoothness metrics, NARJ and FF/MF ratio, distinguished PD from volitional slowness and correlated with time since diagnosis. They are candidate physiological markers of PD-induced bradykinesia.


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