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Effects of wrist tendon vibration on arm tracking in people poststroke. J Neurophysiol 2011 Sep;106(3):1480-8

Date

06/24/2011

Pubmed ID

21697444

Pubmed Central ID

PMC3174817

DOI

10.1152/jn.00404.2010

Abstract

The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the wrist flexor tendons. Position, velocity, and electromyography data were evaluated to compare the quality of arm movements before, during, and after trials with concurrent vibration. Despite tracking a target that moved at a constant velocity, hand trajectories appeared to be segmented, displaying alternating intervals of acceleration and deceleration. Segments were identifiable in tangential velocity data as single-peaked, bell-shaped speed pulses. When tendon vibration was applied at the wrist musculature, stroke subjects experienced improved tracking performance in that hand path lengths and peak speed variability decreased, whereas movement smoothness increased. These performance improvements were accompanied by decreases in the muscle activity during movement. Possible mechanisms behind improved movement control in response to tendon vibration may include improved sensorimotor integration or improved cortical modulation of spinal reflex activity.

Author List

Conrad MO, Scheidt RA, Schmit BD

Authors

Robert Scheidt BS,MS,PhD Associate Professor in the Biomedical Engineering department at Marquette University
Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University




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

Adult
Arm
Female
Humans
Male
Middle Aged
Proprioception
Psychomotor Performance
Stroke
Tendons
Vibration
Wrist