Linked Life Data

7820623

Source:http://linkedlifedata.com/resource/pubmed/id/7820623

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1995-2-14
pubmed:abstractText
Some hypotheses suggest that stretch reflex threshold regulation may be an essential element of motor control. Disturbances in this mechanism may lead to motor dysfunction. We investigated this possibility by comparing stretch reflex threshold regulation in 11 spastic hemiparetic and 6 normal subjects. Subjects sat with their arms fully supported in a forearm and hand mold attached to a manipulandum mounted on and controlled by a torque motor. They remained completely passive while their elbow was extended from 30 degrees flexion through an arc of 100 degrees. Displacement and velocity of the forearm were measured as well as EMG signals from 2 elbow flexors and 2 elbow extensors, when the elbow flexors were stretched at each of 7 velocities. Velocities ranged from 8 to 160 degrees/s for hemiparetic subjects and from 32 to 300 degrees/s for normal subjects. Phase diagrams (velocity versus angle) were plotted and the threshold angles (lambda) for muscle activation at each velocity of stretch were used to determine the static stretch reflex threshold (lambda) and the slope (mu) of the relationship between the lambda s and velocity. Our main findings were that static and dynamic stretch reflex thresholds were decreased in spastic hemiparetic compared to normal subjects and that the thresholds depended on velocity. The static threshold value correlated with the severity of clinically measured spasticity. In addition, the range of regulation of lambda was decreased in the patients compared to normal. This may explain some of the problems of force and position regulation as well as hypertonus (and weakness) common to these patients.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
657
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
23-30
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
The role of stretch reflex threshold regulation in normal and impaired motor control.
pubmed:affiliation
School of Rehabilitation, University of Montreal, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't