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Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke
Stroke lesions interrupt descending corticofugal fibers that provide the volitional control of the upper and lower extremities. Despite the evident manifestation of movement impairments post-stroke during standing and gait, neural constraints in the ability to generate joint torque combinations in t...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Frontiers Media S.A.
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050392/ https://www.ncbi.nlm.nih.gov/pubmed/30050495 http://dx.doi.org/10.3389/fneur.2018.00564 |
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author | Sánchez, Natalia Acosta, Ana M. López-Rosado, Roberto Dewald, Julius P. A. |
author_facet | Sánchez, Natalia Acosta, Ana M. López-Rosado, Roberto Dewald, Julius P. A. |
author_sort | Sánchez, Natalia |
collection | PubMed |
description | Stroke lesions interrupt descending corticofugal fibers that provide the volitional control of the upper and lower extremities. Despite the evident manifestation of movement impairments post-stroke during standing and gait, neural constraints in the ability to generate joint torque combinations in the lower extremities are not yet well determined. Twelve chronic hemiparetic participants and 8 age-matched control individuals participated in the present study. In an isometric setup, participants were instructed to combine submaximal hip extension or ankle plantarflexion torques with maximal hip abduction torques. Statistical analyses were run using linear mixed effects models. Results for the protocol combining hip extension and abduction indicate that participants post-stroke have severe limitations in the amount of hip abduction torque they can generate, dependent upon hip extension torque magnitude. These effects are manifested in the paretic extremity by the appearance of hip adduction torques instead of hip abduction at higher levels of hip extension. In the non-paretic extremity, significant reductions of hip abduction were also observed. In contrast, healthy control individuals were capable of combining varied levels of hip extension with maximal hip abduction. When combining ankle plantarflexion and hip abduction, only the paretic extremity showed reductions in the ability to generate hip abduction torques at increased levels of ankle plantarflexion. Our results provide insight into the neural mechanisms controlling the lower extremity post-stroke, supporting previously hypothesized increased reliance on postural brainstem motor pathways. These pathways have a greater dominance in the control of proximal joints (hip) compared to distal joints (ankle) and lead to synergistic activation of musculature due to their diffuse, bilateral connections at multiple spinal cord levels. We measured, for the first time, bilateral constraints in hip extension/abduction coupling in hemiparetic stroke, again in agreement with the expected increased reliance on bilateral brainstem motor pathways. Understanding of these neural constraints in the post-stroke lower extremities is key in the development of more effective rehabilitation interventions that target abnormal joint torque coupling patterns. |
format | Online Article Text |
id | pubmed-6050392 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-60503922018-07-26 Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke Sánchez, Natalia Acosta, Ana M. López-Rosado, Roberto Dewald, Julius P. A. Front Neurol Neurology Stroke lesions interrupt descending corticofugal fibers that provide the volitional control of the upper and lower extremities. Despite the evident manifestation of movement impairments post-stroke during standing and gait, neural constraints in the ability to generate joint torque combinations in the lower extremities are not yet well determined. Twelve chronic hemiparetic participants and 8 age-matched control individuals participated in the present study. In an isometric setup, participants were instructed to combine submaximal hip extension or ankle plantarflexion torques with maximal hip abduction torques. Statistical analyses were run using linear mixed effects models. Results for the protocol combining hip extension and abduction indicate that participants post-stroke have severe limitations in the amount of hip abduction torque they can generate, dependent upon hip extension torque magnitude. These effects are manifested in the paretic extremity by the appearance of hip adduction torques instead of hip abduction at higher levels of hip extension. In the non-paretic extremity, significant reductions of hip abduction were also observed. In contrast, healthy control individuals were capable of combining varied levels of hip extension with maximal hip abduction. When combining ankle plantarflexion and hip abduction, only the paretic extremity showed reductions in the ability to generate hip abduction torques at increased levels of ankle plantarflexion. Our results provide insight into the neural mechanisms controlling the lower extremity post-stroke, supporting previously hypothesized increased reliance on postural brainstem motor pathways. These pathways have a greater dominance in the control of proximal joints (hip) compared to distal joints (ankle) and lead to synergistic activation of musculature due to their diffuse, bilateral connections at multiple spinal cord levels. We measured, for the first time, bilateral constraints in hip extension/abduction coupling in hemiparetic stroke, again in agreement with the expected increased reliance on bilateral brainstem motor pathways. Understanding of these neural constraints in the post-stroke lower extremities is key in the development of more effective rehabilitation interventions that target abnormal joint torque coupling patterns. Frontiers Media S.A. 2018-07-11 /pmc/articles/PMC6050392/ /pubmed/30050495 http://dx.doi.org/10.3389/fneur.2018.00564 Text en Copyright © 2018 Sánchez, Acosta, López-Rosado and Dewald. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Neurology Sánchez, Natalia Acosta, Ana M. López-Rosado, Roberto Dewald, Julius P. A. Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title | Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title_full | Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title_fullStr | Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title_full_unstemmed | Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title_short | Neural Constraints Affect the Ability to Generate Hip Abduction Torques When Combined With Hip Extension or Ankle Plantarflexion in Chronic Hemiparetic Stroke |
title_sort | neural constraints affect the ability to generate hip abduction torques when combined with hip extension or ankle plantarflexion in chronic hemiparetic stroke |
topic | Neurology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6050392/ https://www.ncbi.nlm.nih.gov/pubmed/30050495 http://dx.doi.org/10.3389/fneur.2018.00564 |
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