Effects of tDCS in M1 and DLPFC on Pain Processing in Healthy Volunteers

Study Overview
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Brief Summary
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The purpose of this study is to evaluate the effects of a direct current applied transcranial over two cortical areas on healthy volunteers' pain processing.

Official Title
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Effects of Transcranial Direct Current Stimulation on Primary Cortex and Prefrontal Dorsolateral Cortex in Pain Processing on Healthy Volunteers: A Triple Blind Randomized Controlled Trial.

Conditions
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Pain Processing in Healthy Volunteers

Intervention / Treatment
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* Device: Transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 18 and 40 years Comprehension of the study tasks Exclusion Criteria: Presence of pain in the previous 6 months Altered sensitivity in the tested regions Intolerance to electrotherapy Presence of pacemakers or any other implanted device Ulcers or scars in the skin at the location of the electrodes Treatment with direct current stimulation within one week Pregnancy Frequent headaches Epilepsy History of neuromuscular disease Previous clinical history of cervical surgery Injuries or surgery affecting the upper limb diabetes mellitus Cardiovascular diseases Oncological diseases Consumption of analgesic drugs 7 days before the study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Three groups cross over study with two intervention groups and one sham group.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: M1 stimulation<br>A 20 minutes 1mA direct current stimulation over left M1. | Device: Transcranial direct current stimulation<br>* Direct current application over the scalp to stimulate and change the excitability of the cortical areas underneath the electrodes (in this case left primary motor cortex and left dorsolateral prefrontal cortex).<br>|
| Active Comparator: M1+DLPFC stimulation<br>A 20 minutes 1mA direct current stimulation over left M1 and 1mA direct current stimulation over left DLPFC. | Device: Transcranial direct current stimulation<br>* Direct current application over the scalp to stimulate and change the excitability of the cortical areas underneath the electrodes (in this case left primary motor cortex and left dorsolateral prefrontal cortex).<br>|
| Sham Comparator: Sham stimulation<br>A 20 minutes sham stimulation where the device only is working first 30s and last 30s of the intervention and have a 10 seconds fade out in intensity at each ramp. | Device: Transcranial direct current stimulation<br>* Direct current application over the scalp to stimulate and change the excitability of the cortical areas underneath the electrodes (in this case left primary motor cortex and left dorsolateral prefrontal cortex).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Conditioned Pain Modulation | Pain pressure threshold change after a painful ischemic stimulus | Pre-intervention and immediately after treatment | 
| Pain pressure algometer temporal summation | Change in pain perceived between the first and tenth painful pressure stimulus | Pre-intervention and immediately after treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain pressure threshold | Measurement of pressure applied until the perception of pain | Pre-intervention and immediately after treatment | 
| Pain pressure tolerance | Measurement of maximal painful pressure tolerate using a pressure algometer | Pre-intervention and immediately after treatment | 
| Neural mechanosensitivity | Measurement of range of motion achieved until the perception of tension | Pre-intervention and immediately after treatment | 
| Cold hyperalgesia with a cold pack | Pain rated in a visual analogue scale after 10 seconds of a cold stimulus | Pre-intervention and immediately after treatment | 
| Isometric grip strength | Maximal pressure achieved in a isometric gripping task | Pre-intervention and immediately after treatment |