Elaboration of a Pre-surgery Mapping Protocol of Primary Motor Cortex, Prior to an Implementation of a Stimulation of Primary Motor Cortex for Patients With Deafferentiation of Brachial Plexus Pain

Study Overview
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Brief Summary
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In the context of an insufficiency of clinical results for cortical stimulation in treatment of brachial plexus post-avulsion pains, one of the possibility for failure is the bad pre-surgery mapping of the area to stimulated bu the usual methods (PEM et fMRI). This purpose of this study is to realise a precise mapping of the primary motor cortex post brachial plexus avulsion. The principal endpoints is to identify and test the reliability of a muscular marker for which the cortical representation is localized immediately next to the superior member area. Several muscles of cephalic, cervical and chest area will be investigate. The methods used will be mono-shock transcranial magnetic stimulation (mTMS) and functional MRI. Concerning mTMS, several methods will be tested: best position on the scalp, realisation of outputs maps with extreme points average method, with mass center method. Concerning fMRI studies, the above paradigms will be checked: imaginary movements of hand, blow up and down abdomen, eyes winking. Statistical tests will confirm the best muscle candidate and will permit to evaluate the reliability of the method.

Official Title
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Elaboration of a Pre-surgery Mapping Protocol of Primary Motor Cortex, Prior to an Implementation of a Stimulation of Primary Motor Cortex for Patients With Deafferentiation of Brachial Plexus Pain

Conditions
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Painful Avulsion of Brachial Plexus

Intervention / Treatment
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* Procedure: fMRI
* Procedure: mTMS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: For all groups: informed consent, social insurance For group 1 painful BPA: consulting to the Nantes'UH for pain of BPA, EVA≥4, neurological deficiency partial or total For group 2 painless BPA: EVA<4, neurological deficiency partial or total, matching with group 1 on the neurological deficiency For group 3 Healthy: matching with group 1 on age ±10 years Exclusion Criteria: No informed consent Medical history of epilepsy Pregnant women Contra-indication to MRI

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Painless plexus<br>Patient with a painless avulsion of brachial plexus | Procedure: fMRI<br> <br> Procedure: mTMS<br> <br> |
| Active Comparator: Healthy<br>Healthy volunteers | Procedure: fMRI<br> <br> Procedure: mTMS<br> <br> |
| Experimental: Painful plexus<br>Patient with a painful avulsion of brachial plexus | Procedure: fMRI<br> <br> Procedure: mTMS<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Identify the 2 muscles (lateral and medial) lining the representation of superior member according to Penfield's homunculus. | Spatial coordinates (xyz): calculation of the center of gravity of cortical surface suggestive of a specific muscle, using data acquired during each session. |  | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of primary outcome depending on cortical center | Calculation of cortical center evoking the maximal PEM |  | 
| Evaluation of primary outcome depending on the center of cortical area | Calculation of the center of the cortical area suggestive of a precised muscle |  | 
| Evaluation of primary outcome depending on cortical surface | Calculation of cortical surface suggestive of a precised muscle |  | 
| Pain intensity | Pain intensity by using an visual analogic scale |  | 
| Ghost sensations intensity | Ghost sensations intensity by a questionnaire |  | 
| Amplitude of PEM | calculation of the amplitude of PEM for a precised muscle. |  |