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Multijoint reflex responses to constant-velocity volitional movements of the stroke elbow. J Neurophysiol 2009 Sep;102(3):1398-410

Date

06/26/2009

Pubmed ID

19553478

DOI

10.1152/jn.90972.2008

Scopus ID

2-s2.0-70349299884   10 Citations

Abstract

Multijoint reflex coupling could impact the voluntary control of functional arm movements in people post stroke. The multijoint responses to active-assist, constant-velocity movements of the elbow joint were measured in 14 individuals post stroke and 9 neurologically intact controls. Resulting responses in the stroke group illustrated a change in the reflex coupling of the elbow and shoulder muscles compared with passive perturbations of the spastic elbow. Voluntary effort during constant-velocity elbow extension resulted in reflex shoulder abduction, differing from the reflex coupling observed between the elbow flexors and shoulder adductors observed during passive elbow extension. These results suggest that post stroke, voluntary drive alters reflex coupling of the elbow and shoulder. Flexion of the elbow during active-assist also resulted in reflex coupling. Shoulder abduction torque decreased with constant-velocity flexion of the elbow; however, no net adduction was observed at the end of the perturbation. Shoulder flexion/extension and internal/external rotation torque responses demonstrated similar modulations to imposed active-assist perturbations of the elbow in subjects post stroke. Responses were absent during passive perturbations of the control elbow; however, shoulder torque modulations were observed during constant-velocity, active-assist tasks. The active-assist response patterns in controls were similar to stroke subjects during the extension task but opposite during flexion of the elbow. This study provides evidence of a neural coupling between elbow and shoulder muscles and a modulation of this coupling during voluntary drive of the spastic arm.

Author List

Sangani SG, Starsky AJ, McGuire JR, Schmit BD

Authors

John R. McGuire MD Professor in the Physical Medicine and Rehabilitation department at Medical College of Wisconsin
Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University
Andrew Starsky BS,PhD,MPT Assistant Professor in the Physical Therapy department at Marquette University




MESH terms used to index this publication - Major topics in bold

Action Potentials
Adult
Aged
Analysis of Variance
Elbow
Elbow Joint
Electromyography
Female
Humans
Male
Middle Aged
Movement
Muscle, Skeletal
Reflex
Stroke
Torque
Young Adult