Large motor units are selectively affected following a stroke

M. Lukács, L. Vécsei, S. Beniczky

Research output: Contribution to journalArticle

57 Citations (Scopus)


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 macro-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.

Original languageEnglish
Pages (from-to)2555-2558
Number of pages4
JournalClinical Neurophysiology
Issue number11
Publication statusPublished - Nov 1 2008


  • Macro-EMG
  • Motor unit
  • Recruitment threshold
  • Stroke

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)

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