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Optimization and comparison of two methods for spike train estimation in an unfused tetanic contraction of low threshold motor units

Rohlén, Robin LU orcid ; Antfolk, Christian LU and Grönlund, Christer (2022) In Journal of Electromyography and Kinesiology 67.
Abstract

Background: Recent findings have shown that imaging voluntarily activated motor units (MUs) by decomposing ultrasound-based displacement images provides estimates of unfused tetanic signals evoked by spinal motoneurons’ neural discharges (spikes). Two methods have been suggested to estimate its spike trains: band-pass filter (BPM) and Haar wavelet transform (HWM). However, the methods’ optimal parameters and which method performs the best are unknown. This study will answer these questions. Method: HWM and BPM were optimized using simulations. Their performance was evaluated based on simulations and 21 experimental datasets, considering their rate of agreement, spike offset, and spike offset variability to the simulated or experimental... (More)

Background: Recent findings have shown that imaging voluntarily activated motor units (MUs) by decomposing ultrasound-based displacement images provides estimates of unfused tetanic signals evoked by spinal motoneurons’ neural discharges (spikes). Two methods have been suggested to estimate its spike trains: band-pass filter (BPM) and Haar wavelet transform (HWM). However, the methods’ optimal parameters and which method performs the best are unknown. This study will answer these questions. Method: HWM and BPM were optimized using simulations. Their performance was evaluated based on simulations and 21 experimental datasets, considering their rate of agreement, spike offset, and spike offset variability to the simulated or experimental spikes. Results: A range of parameter sets that resulted in the highest possible agreement with simulated spikes was provided. Both methods highly agreed with simulated and experimental spikes, but HWM was a better spike estimation method than BPM because it had a higher agreement, less bias, and less variation (p < 0.001). Conclusions: The optimized HWM will be an important contributor to further developing the identification and analysis of MUs using imaging, providing indirect access to the neural drive of the spinal cord to the muscle by the unfused tetanic signals.

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author
; and
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type
Contribution to journal
publication status
published
subject
in
Journal of Electromyography and Kinesiology
volume
67
article number
102714
publisher
Elsevier
external identifiers
  • scopus:85139291787
  • pmid:36209700
ISSN
1050-6411
DOI
10.1016/j.jelekin.2022.102714
language
English
LU publication?
yes
id
7090d4a8-28a2-4ae7-851b-58df27716dee
date added to LUP
2022-12-09 11:04:02
date last changed
2024-06-13 12:34:22
@article{7090d4a8-28a2-4ae7-851b-58df27716dee,
  abstract     = {{<p>Background: Recent findings have shown that imaging voluntarily activated motor units (MUs) by decomposing ultrasound-based displacement images provides estimates of unfused tetanic signals evoked by spinal motoneurons’ neural discharges (spikes). Two methods have been suggested to estimate its spike trains: band-pass filter (BPM) and Haar wavelet transform (HWM). However, the methods’ optimal parameters and which method performs the best are unknown. This study will answer these questions. Method: HWM and BPM were optimized using simulations. Their performance was evaluated based on simulations and 21 experimental datasets, considering their rate of agreement, spike offset, and spike offset variability to the simulated or experimental spikes. Results: A range of parameter sets that resulted in the highest possible agreement with simulated spikes was provided. Both methods highly agreed with simulated and experimental spikes, but HWM was a better spike estimation method than BPM because it had a higher agreement, less bias, and less variation (p &lt; 0.001). Conclusions: The optimized HWM will be an important contributor to further developing the identification and analysis of MUs using imaging, providing indirect access to the neural drive of the spinal cord to the muscle by the unfused tetanic signals.</p>}},
  author       = {{Rohlén, Robin and Antfolk, Christian and Grönlund, Christer}},
  issn         = {{1050-6411}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of Electromyography and Kinesiology}},
  title        = {{Optimization and comparison of two methods for spike train estimation in an unfused tetanic contraction of low threshold motor units}},
  url          = {{http://dx.doi.org/10.1016/j.jelekin.2022.102714}},
  doi          = {{10.1016/j.jelekin.2022.102714}},
  volume       = {{67}},
  year         = {{2022}},
}