Innervation zone distribution of the biceps brachii muscle examined using voluntary and electrically-evoked high-density surface EMG

Chengjun Huang, Cliff S. Klein, Zhaojian Meng, Yingchun Zhang, Sheng Li, Ping Zhou

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Background: High density surface electromyography (EMG) can be used to estimate muscle innervation zones (IZ). The objective of this study was to compare the differences in the distribution of the biceps brachii (BB) IZ derived from voluntary contractions (VC) and electrical stimulation (ES) of the musculocutaneous nerve. Methods: Surface EMG signals were recorded from the medial and lateral BB with two 64-channel high density electrode matrices in eight healthy men. The surface EMG was recorded at different percentages of the maximal voluntary contraction (MVC) force (20-100% MVC) and at different percentages of the current needed to elicit a maximal M-wave (20-100% Imax). The IZs of the medial and lateral BB were identified from the EMG signals and expressed as a row number within a given medial-lateral column. Results: ES current intensity had no significant effect on the group mean IZ location (p > 0.05). However, The IZ during VC was located more proximally with increasing force (p < 0.05), likely due to muscle shortening. The position of the IZ varied slightly (by up to ~ 8 mm) in a medial-lateral direction under both contraction types, but this spatial effect was not significant. The IZ during ES and weak VC (20, 40% MVC) was similar (p > 0.05), but was more proximal in the latter than the former during 60-100% MVC (p < 0.05). Conclusion: ES can be used to detect spatial differences in IZ location free of the confounding effects of muscle shortening and recruitment order of different sized motor units. The method may prove beneficial for locating the IZ in patients who lack voluntary control of their musculature.

Original languageEnglish (US)
Article number73
JournalJournal of NeuroEngineering and Rehabilitation
Volume16
Issue number1
DOIs
StatePublished - Jun 11 2019

Keywords

  • EMG
  • Electrical stimulation
  • High-density electrode matrices
  • Innervation zone
  • Voluntary contraction

ASJC Scopus subject areas

  • Rehabilitation
  • Health Informatics

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