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Effect of sensory feedback from the proximal upper limb on voluntary isometric finger flexion and extension in hemiparetic stroke subjects. J Neurophysiol 2011 Nov;106(5):2546-56

Date

08/13/2011

Pubmed ID

21832028

Pubmed Central ID

PMC3214108

DOI

10.1152/jn.00522.2010

Abstract

This study investigated the potential influence of proximal sensory feedback on voluntary distal motor activity in the paretic upper limb of hemiparetic stroke survivors and the potential effect of voluntary distal motor activity on proximal muscle activity. Ten stroke subjects and 10 neurologically intact control subjects performed maximum voluntary isometric flexion and extension, respectively, at the metacarpophalangeal (MCP) joints of the fingers in two static arm postures and under three conditions of electrical stimulation of the arm. The tasks were quantified in terms of maximum MCP torque [MCP flexion (MCP(flex)) or MCP extension (MCP(ext))] and activity of targeted (flexor digitorum superficialis or extensor digitorum communis) and nontargeted upper limb muscles. From a previous study on the MCP stretch reflex poststroke, we expected stroke subjects to exhibit a modulation of voluntary MCP torque production by arm posture and electrical stimulation and increased nontargeted muscle activity. Posture 1 (flexed elbow, neutral shoulder) led to greater MCP(flex) in stroke subjects than posture 2 (extended elbow, flexed shoulder). Electrical stimulation did not influence MCP(flex) or MCP(ext) in either subject group. In stroke subjects, posture 1 led to greater nontargeted upper limb flexor activity during MCP(flex) and to greater elbow flexor and extensor activity during MCP(ext). Stroke subjects exhibited greater elbow flexor activity during MCP(flex) and greater elbow flexor and extensor activity during MCP(ext) than control subjects. The results suggest that static arm posture can modulate voluntary distal motor activity and accompanying muscle activity in the paretic upper limb poststroke.

Author List

Hoffmann G, Schmit BD, Kahn JH, Kamper DG

Author

Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University




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

Aged
Arm
Electric Stimulation
Feedback, Sensory
Female
Fingers
Humans
Isometric Contraction
Male
Metacarpophalangeal Joint
Middle Aged
Motor Activity
Muscle, Skeletal
Paresis
Posture
Stroke
Torque
Volition