Muscle weakness and lack of reflex gain adaptation predominate during post-stroke posture control of the wrist

Muscle weakness and lack of reflex gain adaptation predominate during post-stroke posture control of the wrist

Meskers, C.G.M.
Schouten, A.C.
De Groot, J.H.
De Vlugt, E.
Van Hilten, B.J.J.
Van der Helm, F.C.T.
Arendzen, H.J.H.

Mechanical, Maritime and Materials Engineering

Biomechanical Engineering

2009-07-23

Background Instead of hyper-reflexia as sole paradigm, post-stroke movement disorders are currently considered the result of a complex interplay between neuronal and muscular properties, modified by level of activity. We used a closed loop system identification technique to quantify individual contributors to wrist joint stiffness during an active posture task. Methods Continuous random torque perturbations applied to the wrist joint by a haptic manipulator had to be resisted maximally. Reflex provoking conditions were applied i.e. additional viscous loads and reduced perturbation signal bandwidth. Linear system identification and neuromuscular modeling were used to separate joint stiffness into the intrinsic resistance of the muscles including co-contraction and the reflex mediated contribution. Results Compared to an age and sex matched control group, patients showed an overall 50% drop in intrinsic elasticity while their reflexive contribution did not respond to provoking conditions. Patients showed an increased mechanical stability compared to control subjects.

http://resolver.tudelft.nl/uuid:4d003efb-92af-42f0-b370-ebf40a112687

BioMed Central

Journal of NeuroEngineering and Rehabilition, 6 (29), 2009

Institutional Repository

journal article

(c) 2009 © 2009 Meskers et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribu