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A Method for Identification of Mechanical Response of Motor Units in Skeletal Muscle Voluntary Contractions Using Ultrafast Ultrasound Imaging - Simulations and Experimental Tests

Rohlen, Robin LU orcid ; Stalberg, Erik ; Stoverud, Karen Helene ; Yu, Jun and Gronlund, Christer (2020) In IEEE Access 8. p.50299-50311
Abstract

The central nervous system coordinates movement through forces generated by motor units (MUs) in skeletal muscles. To analyze MUs function is essential in sports, rehabilitation medicine applications, and neuromuscular diagnostics. The MUs and their function are studied using electromyography. Typically, these methods study only a small muscle volume (1 mm3) or only a superficial (<1 cm) volume of the muscle. Here we introduce a method to identify so-called mechanical units, i.e., the mechanical response of electrically active MUs, in the whole muscle ( $4\times 4$ cm, cross-sectional) under voluntary contractions by ultrafast ultrasound imaging and spatiotemporal decomposition. We evaluate the performance of the method by... (More)

The central nervous system coordinates movement through forces generated by motor units (MUs) in skeletal muscles. To analyze MUs function is essential in sports, rehabilitation medicine applications, and neuromuscular diagnostics. The MUs and their function are studied using electromyography. Typically, these methods study only a small muscle volume (1 mm3) or only a superficial (<1 cm) volume of the muscle. Here we introduce a method to identify so-called mechanical units, i.e., the mechanical response of electrically active MUs, in the whole muscle ( $4\times 4$ cm, cross-sectional) under voluntary contractions by ultrafast ultrasound imaging and spatiotemporal decomposition. We evaluate the performance of the method by simulation of active MUs' mechanical response under weak contractions. We further test the experimental feasibility on eight healthy subjects. We show the existence of mechanical units that contribute to the tissue dynamics in the biceps brachii at low force levels and that these units are similar to MUs described by electromyography with respect to the number of units, territory sizes, and firing rates. This study introduces a new potential neuromuscular functional imaging method, which could be used to study a variety of questions on muscle physiology that previously were difficult or not possible to address.

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author
; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biomedical engineering, blind source separation, physiology, ultrasonic imaging
in
IEEE Access
volume
8
article number
9032320
pages
13 pages
publisher
IEEE - Institute of Electrical and Electronics Engineers Inc.
external identifiers
  • scopus:85082382191
ISSN
2169-3536
DOI
10.1109/ACCESS.2020.2980053
language
English
LU publication?
no
additional info
Funding Information: This work was supported in part by the Swedish Research Council under Grant dnr 2015-04461, and in part by the Kempe foundations under Grant dnr JCK-1115. Publisher Copyright: © 2013 IEEE.
id
5b2941ec-3b39-41c5-8cf4-9427ca034413
date added to LUP
2023-05-16 00:04:14
date last changed
2023-05-22 12:24:22
@article{5b2941ec-3b39-41c5-8cf4-9427ca034413,
  abstract     = {{<p>The central nervous system coordinates movement through forces generated by motor units (MUs) in skeletal muscles. To analyze MUs function is essential in sports, rehabilitation medicine applications, and neuromuscular diagnostics. The MUs and their function are studied using electromyography. Typically, these methods study only a small muscle volume (1 mm<sup>3</sup>) or only a superficial (&lt;1 cm) volume of the muscle. Here we introduce a method to identify so-called mechanical units, i.e., the mechanical response of electrically active MUs, in the whole muscle ( $4\times 4$ cm, cross-sectional) under voluntary contractions by ultrafast ultrasound imaging and spatiotemporal decomposition. We evaluate the performance of the method by simulation of active MUs' mechanical response under weak contractions. We further test the experimental feasibility on eight healthy subjects. We show the existence of mechanical units that contribute to the tissue dynamics in the biceps brachii at low force levels and that these units are similar to MUs described by electromyography with respect to the number of units, territory sizes, and firing rates. This study introduces a new potential neuromuscular functional imaging method, which could be used to study a variety of questions on muscle physiology that previously were difficult or not possible to address.</p>}},
  author       = {{Rohlen, Robin and Stalberg, Erik and Stoverud, Karen Helene and Yu, Jun and Gronlund, Christer}},
  issn         = {{2169-3536}},
  keywords     = {{Biomedical engineering; blind source separation; physiology; ultrasonic imaging}},
  language     = {{eng}},
  pages        = {{50299--50311}},
  publisher    = {{IEEE - Institute of Electrical and Electronics Engineers Inc.}},
  series       = {{IEEE Access}},
  title        = {{A Method for Identification of Mechanical Response of Motor Units in Skeletal Muscle Voluntary Contractions Using Ultrafast Ultrasound Imaging - Simulations and Experimental Tests}},
  url          = {{http://dx.doi.org/10.1109/ACCESS.2020.2980053}},
  doi          = {{10.1109/ACCESS.2020.2980053}},
  volume       = {{8}},
  year         = {{2020}},
}