Effects of Cerebral and Peripheral Electrical Stimulation on Conditioned Pain Modulation in Healthy Subjects.

Study Overview
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Brief Summary
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The Neuromatrix pain model and new findings on pain chronification process point to a greater efficacy of treatments that address central and peripheral rather than only peripheral structures. Both cerebral and peripheral electrical stimulations can modulate brain areas involved in pain processing. However, their effects on pain modulation systems and clinical outcomes are lacking. This study aims to investigate the efficacy of transcranial direct current stimulation (tDCS) and peripheral electrical stimulation (PES) alone as well tDCS combined with PES on pressure pain threshold and conditioned pain modulation in healthy subjects.

Official Title
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Effects of Cerebral and Peripheral Electrical Stimulation on Conditioned Pain Modulation in Healthy Subjects.

Conditions
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Healthy Volunteers

Intervention / Treatment
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* Procedure: Transcranial direct current stimulation (tDCS)
* Procedure: Peripheral electrical stimulation (PES)
* Procedure: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy subjects without medical complaints. Exclusion Criteria: Concurrent medication likely to affect cognitive performance pregnancy or possible pregnancy history of drug or alcohol abuse or dependence recent head injury (in the last 3 months) history of seizure or stroke.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cerebral stimulation<br>Active transcranial direct current stimulation tDCS: 20 minutes, 2mA, primary motor cortex anode (contralateral to the lesion) and supraorbital cathode (ipsilateral to the lesion). | Procedure: Transcranial direct current stimulation (tDCS)<br>* Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation (NIBS) technique that has been investigated for the management of various chronic pain conditions. However, as a monotherapy for pain relief, this therapy still has controversial results.<br>|
| Experimental: Combined stimulation<br>Active transcranial direct current stimulation combined with active peripheral electrical stimulation (PES) tDCS: 20 minutes, 2mA, primary motor cortex anode (contralateral to the lesion) and supraorbital cathode (ipsilateral to the lesion). PES: 20 minutes, 10Hz (frequency), 100µs (pulse duration), intensity at sensorial level. | Procedure: Transcranial direct current stimulation (tDCS)<br>* Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation (NIBS) technique that has been investigated for the management of various chronic pain conditions. However, as a monotherapy for pain relief, this therapy still has controversial results.<br>Procedure: Peripheral electrical stimulation (PES)<br>* Peripheral electrical stimulation (PES) activates a complex neural network involving a series of neurotransmitters and receptors capable of promoting segmental and extrasegmental analgesia.<br>|
| Sham Comparator: Sham cerebral stimulation<br>Sham transcranial direct current stimulation combined with active peripheral electrical stimulation (PES) tDCS: 20 minutes (30s ON), 2mA, primary motor cortex anode (contralateral to the lesion) and supraorbital cathode (ipsilateral to the lesion). | Procedure: Sham tDCS<br>* Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation (NIBS) technique that has been investigated for the management of various chronic pain conditions. However, as a monotherapy for pain relief, this therapy still has controversial results.<br>|
| Experimental: Peripheral stimulation<br>Active peripheral electrical stimulation (PES). PES: 20 minutes, 10Hz (frequency), 100µs (pulse duration), intensity at sensorial level. | Procedure: Peripheral electrical stimulation (PES)<br>* Peripheral electrical stimulation (PES) activates a complex neural network involving a series of neurotransmitters and receptors capable of promoting segmental and extrasegmental analgesia.<br>Procedure: Sham tDCS<br>* Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation (NIBS) technique that has been investigated for the management of various chronic pain conditions. However, as a monotherapy for pain relief, this therapy still has controversial results.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure pain threshold | Pressure pain threshold (PPT) is defined as the minimum force applied which induces pain. | Pre and Post-test (immediately after tDCS) | 
| Conditioned pain modulation | Conditioned pain modulation paradigms consist of the evaluation of a painful test stimulus followed by a second evaluation either at the same time as a distant, painful conditioning stimulus. PPT will be evaluated following a conditioning stimulus condition (hand immersion in a cold water). | Pre and Post-test (immediately after tDCS) |