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Postural displacement induced by electrical stimulation; A new approach to examine postural recovery

BACKGROUND: Controlling upright posture entails acute adjustments by the neuromuscular system to keep the center of mass (COM) within the limits of a relatively small base of support. Sudden displacement of the COM triggers several strategies and balance recovery mechanisms to prevent excessive COM...

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Autores principales: Tahayori, Behdad, Tahayori, Bahman, Mehdizadeh, Alireza, Koceja, David M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387811/
https://www.ncbi.nlm.nih.gov/pubmed/35981077
http://dx.doi.org/10.1371/journal.pone.0273282
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author Tahayori, Behdad
Tahayori, Bahman
Mehdizadeh, Alireza
Koceja, David M.
author_facet Tahayori, Behdad
Tahayori, Bahman
Mehdizadeh, Alireza
Koceja, David M.
author_sort Tahayori, Behdad
collection PubMed
description BACKGROUND: Controlling upright posture entails acute adjustments by the neuromuscular system to keep the center of mass (COM) within the limits of a relatively small base of support. Sudden displacement of the COM triggers several strategies and balance recovery mechanisms to prevent excessive COM displacement. NEW METHOD: We have examined and quantified a new approach to induce an internal neuromuscular perturbation in standing posture on 15 healthy individuals to provide an insight into the mechanism of loss of balance (LOB). The method comprises eliciting an H-reflex protocol while subjects are standing which produces a contraction in soleus and gastrocnemius muscles. We have also defined analytical techniques to provide biomarkers of balance control during perturbation. We used M-Max unilaterally or bilaterally and induced a forward or sideway perturbation. The vector analysis and the Equilibrium Point calculations defined here can quantify the amplitude, direction, and evolution of the perturbation. RESULTS: Clear patterns of loss of balance due to stimulation was observed. Compared to quiet standing, the density of the EPs substantially increased in the perturbation phase. Leftward stimulation produced significantly higher number of EPs compared to the bilateral stimulation condition which could be due to the fact that the left leg was the nondominant side in all our subjects. COMPARISON AND CONCLUSION: In this study we provide a proof-of-concept technique for examining recovery from perturbation. The advantage of this technique is that it provides a safe perturbation, is internally induced at the spinal cord level, and is free from other factors that might complicate the recovery analysis (e.g., locomotion and the integration of the spinal pattern generator and cutaneous pathways in mediating changes). We have shown that the perturbation induced by this method can be quantified as vectors. We have also shown that the density of instantaneous equilibrium points (EPs) could be a good biomarker for defining and examining the perturbation phase. Thus, this protocol and analysis provides a unique individual assessment of recovery which can be used to assess interventions. Finally, given that the maximal motor response is used as the perturbation (e.g., M-max) it is highly reliable and reproducible within an individual patient.
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spelling pubmed-93878112022-08-19 Postural displacement induced by electrical stimulation; A new approach to examine postural recovery Tahayori, Behdad Tahayori, Bahman Mehdizadeh, Alireza Koceja, David M. PLoS One Research Article BACKGROUND: Controlling upright posture entails acute adjustments by the neuromuscular system to keep the center of mass (COM) within the limits of a relatively small base of support. Sudden displacement of the COM triggers several strategies and balance recovery mechanisms to prevent excessive COM displacement. NEW METHOD: We have examined and quantified a new approach to induce an internal neuromuscular perturbation in standing posture on 15 healthy individuals to provide an insight into the mechanism of loss of balance (LOB). The method comprises eliciting an H-reflex protocol while subjects are standing which produces a contraction in soleus and gastrocnemius muscles. We have also defined analytical techniques to provide biomarkers of balance control during perturbation. We used M-Max unilaterally or bilaterally and induced a forward or sideway perturbation. The vector analysis and the Equilibrium Point calculations defined here can quantify the amplitude, direction, and evolution of the perturbation. RESULTS: Clear patterns of loss of balance due to stimulation was observed. Compared to quiet standing, the density of the EPs substantially increased in the perturbation phase. Leftward stimulation produced significantly higher number of EPs compared to the bilateral stimulation condition which could be due to the fact that the left leg was the nondominant side in all our subjects. COMPARISON AND CONCLUSION: In this study we provide a proof-of-concept technique for examining recovery from perturbation. The advantage of this technique is that it provides a safe perturbation, is internally induced at the spinal cord level, and is free from other factors that might complicate the recovery analysis (e.g., locomotion and the integration of the spinal pattern generator and cutaneous pathways in mediating changes). We have shown that the perturbation induced by this method can be quantified as vectors. We have also shown that the density of instantaneous equilibrium points (EPs) could be a good biomarker for defining and examining the perturbation phase. Thus, this protocol and analysis provides a unique individual assessment of recovery which can be used to assess interventions. Finally, given that the maximal motor response is used as the perturbation (e.g., M-max) it is highly reliable and reproducible within an individual patient. Public Library of Science 2022-08-18 /pmc/articles/PMC9387811/ /pubmed/35981077 http://dx.doi.org/10.1371/journal.pone.0273282 Text en © 2022 Tahayori et al https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Tahayori, Behdad
Tahayori, Bahman
Mehdizadeh, Alireza
Koceja, David M.
Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title_full Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title_fullStr Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title_full_unstemmed Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title_short Postural displacement induced by electrical stimulation; A new approach to examine postural recovery
title_sort postural displacement induced by electrical stimulation; a new approach to examine postural recovery
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9387811/
https://www.ncbi.nlm.nih.gov/pubmed/35981077
http://dx.doi.org/10.1371/journal.pone.0273282
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