Structural and Functional Brain Reorganization in Neuropathic Pain. Influences of the Loss of Sensitivity and the Atrophy Cortical on Activations Due to Stimulation Allodynic

Study Overview
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Brief Summary
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Neuropathic pain is a medical condition involving allodynia (painful perceptions in response to stimuli that normally are not) and spontaneous pain (occurring at rest, without stimulation). This pain is secondary to nervous system injury affecting the sensory system. The lesion is either at the nerve endings of the spinal cord or brain. It induces a loss of sensitivity and reorganization of brain activity. Previous studies in functional neuroimaging have focused on brain areas activated during allodynic stimuli compared to non-painful stimuli. The abnormalities have been reported, but it was not possible to conclude formally. The objective of this study is to understand the brain dysfunction that induces allodynic pain considering the deafferentation of each patient and possible cortical losses.

Official Title
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Structural and Functional Brain Reorganization in Neuropathic Pain. Influences of the Loss of Sensitivity and the Atrophy Cortical on Activations Due to Stimulation Allodynic

Conditions
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Neuropathic Pain

Intervention / Treatment
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* Other: stimulation on painful area (area allodynic)
* Other: same stimulation on non-painful area
* Radiation: MRI scan


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: with neuropathic pain in the case of central lesions, the lesion must be unique and small treatment not stable opioid for one week consent signed Exclusion Criteria: severe psychiatric history presence of an evolutive lesion, expansive, cancerous or tumorous underlying patient needing of opioid therapy contraindication at MRI scan

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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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: patients with pain allodynic peripheral<br> | Other: stimulation on painful area (area allodynic)<br>* these stimulations will be performed either with a brush, with a cold block or with forced air (cold air or air to ambient temp) : calibrated to induce pain bearable. stimulations for 6 seconds<br>Other: same stimulation on non-painful area<br>* these stimulations will be performed either with a brush, with a cold block or with forced air (cold air or air to ambient temp) : calibrated to induce pain bearable. stimulations for 6 seconds<br>Radiation: MRI scan<br>* 2 sessions for 10 minutes : 11 controls stimulations for 6 s each spaced 20 s without stimulation. 11 allodynic stimulations for 6 s each spaced 20 s without stimulation.<br>|
| Other: patients with pain allodynic central<br> | Other: stimulation on painful area (area allodynic)<br>* these stimulations will be performed either with a brush, with a cold block or with forced air (cold air or air to ambient temp) : calibrated to induce pain bearable. stimulations for 6 seconds<br>Other: same stimulation on non-painful area<br>* these stimulations will be performed either with a brush, with a cold block or with forced air (cold air or air to ambient temp) : calibrated to induce pain bearable. stimulations for 6 seconds<br>Radiation: MRI scan<br>* 2 sessions for 10 minutes : 11 controls stimulations for 6 s each spaced 20 s without stimulation. 11 allodynic stimulations for 6 s each spaced 20 s without stimulation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the deafferentation rate | the deafferentation rate measured with thermo-test | at baseline | 
| gray matter rate | gray matter rate measured with MRI scan | at baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Analysis pain | Measured by visual analogue scale (0 to 10) | at baseline |