Anal sphincter electromyography: Editing of sampled motor unit action potentials

W. Thomas Gregory, Amanda L. Clark, Joshua Johnson, Kimberly Willis, Amy Stuyvesant, Jau Shin Lou

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


During multi-motor unit action potential (MUAP) analysis of the tonically contracted external anal sphincter (EAS), a mild interference pattern often obscures the baseline, affecting the algorithm's ability to determine accurate boundaries of detected MUAPs. To assess the equivalence of methods of editing and selecting candidate MUAPs from the EAS, 17 nulliparous women underwent concentric needle electromyography (EMG) of the EAS using multi-MUAP software. The selected MUAPs either were accepted without question ("automated") , or a subset was deleted due to a noisy baseline ("manual-deletion") or manually marked ("manual-mark"). A second examiner repeated the analysis. Each examiner found that the two editing methods were equivalent and yielded results that differed from those obtained by automated analysis of unedited data. However, there was a moderate difference in MUAP amplitude when the manual-deletion method was compared between the two examiners. Editing of selected EAS MUAPs during multi-MUAP analysis is required, and development of common protocols is essential to enable meaningful comparisons between similar studies.

Original languageEnglish (US)
Pages (from-to)256-259
Number of pages4
JournalMuscle and Nerve
Issue number2
StatePublished - Feb 2005


  • Accuracy
  • External anal sphincter
  • Multi-MUAP analysis
  • Normative data
  • Standardization

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)


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