Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation

Charalambos C. Charalambous; Jing Nong Liang; Steve A. Kautz; Mark S. George; Mark G. Bowden

doi:10.3791/58944

Navegou de avaliação bilateral das vias corticoespinhal dos músculos do tornozelo utilizando esti...

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JoVE Journal Neuroscience

Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation

Navegou de avaliação bilateral das vias corticoespinhal dos músculos do tornozelo utilizando estimulação magnética transcraniana

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11:06 min

February 19, 2019

DOI: 10.3791/58944-v

Charalambos C. Charalambous^1,2, Jing Nong Liang^3,4, Steve A. Kautz^2,5, Mark S. George^5,6, Mark G. Bowden^2,5,7

¹Department of Neurology,New York University School of Medicine, ²Department of Health Sciences and Research,Medical University of South Carolina, ³Department of Physical Therapy,University of Nevada Las Vegas, ⁴Department of Health Professions,Medical University of South Carolina, ⁵Ralph H. Johnson VA Medical Center, ⁶Department of Psychiatry,Medical University of South Carolina, ⁷Division of Physical Therapy,Medical University of South Carolina

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Overview

This protocol details a standardized method for assessing the corticomotor responses of the tibialis anterior and soleus muscles using transcranial magnetic stimulation (TMS) and neuronavigation. It addresses the challenges of detecting motor-evoked potentials in distal lower extremity muscles during both rest and voluntary activation.

Key Study Components

Area of Science

Neuroscience
Motor control
Electrophysiology

Background

Standardizing assessments of lower extremity muscles is crucial for motor control studies.
This technique is beneficial for both neurologically healthy individuals and stroke patients.
Prior literature has focused primarily on the tibialis anterior with varying methodologies.

Purpose of Study

To standardize lower extremity assessments using TMS.
To identify knowledge gaps regarding motor control during gait.
To consolidate various approaches within existing literature.

Methods Used

This study employs a neuronavigation system alongside TMS.
Key muscles examined include the tibialis anterior and soleus, with detailed electrode placement procedures.
Specific steps involve verifying signal quality and locating motor hotspots bilaterally.
Baseline signal quality is verified through specific testing protocols to minimize noise interference.

Main Results

The method enhances the clarity and reliability of EMG readings for motor assessments.
Corticomotor responses can be accurately measured during tonic voluntary activations.
Identifying the hot spot for each muscle aids in more effective stimulation protocols.
This standardization allows for improved comparison across studies and subjects.

Conclusions

This study provides a robust protocol for bilateral corticomotor response assessments.
The methodology enables the exploration of neural mechanisms underlying motor control and gait.
Identifying and addressing interfering factors can lead to more insightful research outcomes.

Frequently Asked Questions

What are the advantages of using this protocol?

This protocol standardizes the assessment of lower extremity muscle activity, improving comparability of results across different studies.

How is the electrical activity of muscles assessed?

Electromyographic signals are recorded from the tibialis anterior and soleus while subjecting them to TMS during voluntary activations.

What steps are involved in setting up the neuronavigation system?

Subjects' MRI files are uploaded and then co-registered to identify key anatomical landmarks for accurate TMS targeting.

How does the method ensure signal quality?

Signal quality is verified through preliminary tests, ensuring minimal noise before gathering data during the actual assessments.

What types of outcomes are measured during the study?

The primary outcomes include the amplitude and latency of motor-evoked potentials evoked by TMS in the assessed muscles.

O presente protocolo descreve a avaliação simultânea, bilateral da resposta corticomotor do sóleo e tibial anterior durante a ativação voluntária resto e tônico, usando uma estimulação magnética de transcranial de pulso único e neuronavigation sistema.

Este protocolo é criticamente importante porque padroniza uma abordagem com uma tarefa muito difícil de detectar potenciais criados pelo motor nos músculos da extremidade inferior distal. A principal vantagem dessa técnica é que ela consolida a literatura associada à estimulação da extremidade inferior, que muitas vezes foca apenas na tibialis anterior e utiliza uma variedade de técnicas. Estudamos essa técnica em indivíduos neurologicamente saudáveis, bem como aqueles com derrame.

No entanto, a importância da técnica está na padronização de avaliações de extremidades inferiores. A técnica permite a oportunidade de identificar as lacunas em nossa compreensão do controle motor durante a marcha e revisita pesquisas que não permitiram o controle de fatores interferentes. Demonstrando o procedimento estarão John Kindred, PhD, um estudioso de pós-doutorado, e Brian Cence, coordenador de pesquisa, ambos do nosso laboratório de pesquisa.

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