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Optimal control of reaching is disturbed in complex regional pain syndrome: a single-case study

Authors Osumi M, Sumitani M, Kumagaya S, Morioka S

Received 3 August 2016

Accepted for publication 15 November 2016

Published 12 January 2017 Volume 2017:10 Pages 167—173


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Michael Schatman

Michihiro Osumi,1 Masahiko Sumitani,2 Shin-ichiro Kumagaya,3 Shu Morioka1

1Neurorehabilitation Research Center, Kio University, Nara, 2Department of Pain and Palliative Medicine, The University of Tokyo Hospital, 3Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo, Japan

Objective: Disturbance of goal-directed motor control may cause or exacerbate pathological pain in patients with complex regional pain syndrome (CRPS). We conducted a single-case study about motor control involved in reaching with a patient with CRPS in an upper limb.
Methods: Using a three-dimensional measurement system, we recorded reaching movement trajectories of the intact and affected hand before and after pain alleviation by therapeutic nerve blockade. We assessed degrees of tremor in the acceleration phase (from start until maximum peak velocity) and the deceleration phase (from maximum peak velocity until goal). To quantify the smoothness of reaching movements, we analyzed the curves of the trajectories during the initial movement phase (from start and maximum peak acceleration).
Results: The results showed that the tremor of the affected hand was greater than that of the intact hand during the deceleration phase, both before and after pain alleviation. Reaching trajectories of the intact hand smoothly traced curves convexed toward the intact side, while those of the affected hand represented unnaturally rectilinear functions associated with the loss of smooth movements. Further, these unnatural trajectories partially recovered after pain alleviation.
Conclusion: Disturbance of sensorimotor integration and pain-related fear might affect goal-directed motor control in CRPS patients.

Keywords: reaching movement, complex regional pain syndrome, sensorimotor integration, motor control

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