Large motor units are selectively affected following a stroke

Objective: Previous Studies have revealed a loss of functioning motor units in stroke patients. However, it remained unclear whether the motor units are affected randomly or in some specific pattern. We assessed whether there is a selective loss of the large (high recruitment threshold) or the small...

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Bibliographic Details
Main Authors: Lukács Melinda
Vécsei László
Beniczky Sándor
Format: Article
Published: Elsevier 2008
Series:CLINICAL NEUROPHYSIOLOGY 119 No. 11
doi:10.1016/j.clinph.2008.08.005

mtmt:3167476
Online Access:http://publicatio.bibl.u-szeged.hu/9970
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Summary:Objective: Previous Studies have revealed a loss of functioning motor units in stroke patients. However, it remained unclear whether the motor units are affected randomly or in some specific pattern. We assessed whether there is a selective loss of the large (high recruitment threshold) or the small (low recruitment threshold) motor units following a stroke. Methods: Forty-five stroke patients and 40 healthy controls participated in the study. Macro-EMG was recorded from the abductor digiti minimi muscle at two levels of force output (low and high). The median macro motor unit potential (macro-MUP) amplitude on the paretic side was compared with those on the unaffected side and in the controls. Results: In the control group and on the unaffected side, the rnacro-MUPs were significantly larger at the high force output than at the low one. However, on the paretic side the macro-MUPs at the high force output had the same amplitude as those recorded at the low force output. These changes correlated with the severity of the paresis. Conclusions: Following a stroke, there is a selective functional loss of the large, high-threshold motor units. These changes are related to the severity of the symptoms. Significance: Our findings furnish further insight into the pathophysiology of the motor deficit following a stroke. (C) 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.
Physical Description:2555-2558
ISSN:1388-2457