Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis

Abstract Objective Multiple Sclerosis (MS) is often accompanied by myelopathy, which may be associated with progressive worsening. A specific finding of MS‐associated myelopathy is McArdle sign, wherein neck flexion is associated with prominent increased limb weakness relative to that detected with...

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Main Authors: Nathan D. Schilaty, Filippo Savoldi, Zahra Nasr, Brian G. Weinshenker
Format: Article
Language:English
Published: Wiley 2022-04-01
Series:Annals of Clinical and Translational Neurology
Online Access:https://doi.org/10.1002/acn3.51526
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author Nathan D. Schilaty
Filippo Savoldi
Zahra Nasr
Brian G. Weinshenker
author_facet Nathan D. Schilaty
Filippo Savoldi
Zahra Nasr
Brian G. Weinshenker
author_sort Nathan D. Schilaty
collection DOAJ
description Abstract Objective Multiple Sclerosis (MS) is often accompanied by myelopathy, which may be associated with progressive worsening. A specific finding of MS‐associated myelopathy is McArdle sign, wherein neck flexion is associated with prominent increased limb weakness relative to that detected with neck extension. In this study, we characterized neuromotor control properties of finger extensors in association with the McArdle sign. Methods A custom‐built device was utilized to monitor torque production of the wrist extensors with simultaneous recording of surface electromyography of the extensor digitorum. The electromyography was decomposed and analyzed via both linear and nominal regressions. Results Linear regressions demonstrated a strong difference between groups for MS from healthy controls and other myelopathies for motor unit action potential amplitude and average firing rate (p < 0.001). Further, linear regression demonstrated good correlations of neuromotor variables to mechanical torque output (0.24 ≤ R2 ≤ 0.76). Nominal regression distinguished MS from healthy controls with an AUC of 0.87, specificity of 0.97, and sensitivity of 0.64. Nominal regression of MS from other myelopathies demonstrated an AUC of 0.88, specificity of 0.85, and sensitivity of 0.79. Interpretation These data demonstrate the neuromotor control factors that largely determine muscle force production change with the observation of McArdle sign; these neuromotor control factors can differentiate MS from both healthy controls and other myelopathy conditions.
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spelling doaj.art-b549f257fedc47aba5191d3a716d60db2022-12-21T19:00:19ZengWileyAnnals of Clinical and Translational Neurology2328-95032022-04-019451552810.1002/acn3.51526Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosisNathan D. Schilaty0Filippo Savoldi1Zahra Nasr2Brian G. Weinshenker3Department of Neurosurgery & Brain Repair University of South Florida Tampa Florida USADepartment of Neurology Mayo Clinic Rochester Minnesota USADepartment of Neurology Mayo Clinic Rochester Minnesota USADepartment of Neurology Mayo Clinic Rochester Minnesota USAAbstract Objective Multiple Sclerosis (MS) is often accompanied by myelopathy, which may be associated with progressive worsening. A specific finding of MS‐associated myelopathy is McArdle sign, wherein neck flexion is associated with prominent increased limb weakness relative to that detected with neck extension. In this study, we characterized neuromotor control properties of finger extensors in association with the McArdle sign. Methods A custom‐built device was utilized to monitor torque production of the wrist extensors with simultaneous recording of surface electromyography of the extensor digitorum. The electromyography was decomposed and analyzed via both linear and nominal regressions. Results Linear regressions demonstrated a strong difference between groups for MS from healthy controls and other myelopathies for motor unit action potential amplitude and average firing rate (p < 0.001). Further, linear regression demonstrated good correlations of neuromotor variables to mechanical torque output (0.24 ≤ R2 ≤ 0.76). Nominal regression distinguished MS from healthy controls with an AUC of 0.87, specificity of 0.97, and sensitivity of 0.64. Nominal regression of MS from other myelopathies demonstrated an AUC of 0.88, specificity of 0.85, and sensitivity of 0.79. Interpretation These data demonstrate the neuromotor control factors that largely determine muscle force production change with the observation of McArdle sign; these neuromotor control factors can differentiate MS from both healthy controls and other myelopathy conditions.https://doi.org/10.1002/acn3.51526
spellingShingle Nathan D. Schilaty
Filippo Savoldi
Zahra Nasr
Brian G. Weinshenker
Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
Annals of Clinical and Translational Neurology
title Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
title_full Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
title_fullStr Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
title_full_unstemmed Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
title_short Neuromotor control associates with muscle weakness observed with McArdle sign of multiple sclerosis
title_sort neuromotor control associates with muscle weakness observed with mcardle sign of multiple sclerosis
url https://doi.org/10.1002/acn3.51526
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