The Effect of Transcranial Direct Current Stimulation of the Primary Motor and Somatosensory Cortex on Pain Thresholds.

Study Overview
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Brief Summary
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The purpose of this study is to investigate the modulatory effect of a novel tDCS configuration on the pain sensitivity in healthy subjects.

Detailed Description
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The purpose of this study is to investigate the modulatory effect of a single session 20 min anodal primary motor cortex (M1) and cathodal primary somatosensory cortex (S1) transcranial direct current stimulation (tDCS) on the pain sensitivity on the descending part of musculus trapezius in healthy young adults.

Official Title
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The Modulatory Effect of Anodal Primary Motor Cortex and Cathodal Primary Somatosensory Cortex Transcranial Direct Current Stimulation on Pain Thresholds in the Neck Musculature.

Conditions
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Healthy

Intervention / Treatment
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* Device: Active tDCS
* Device: Sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy Age between 18-30 years Living in Denmark Exclusion Criteria: Pregnancy Drug addiction defined as the use of cannabis, opioids or other drugs Current use of opioids, antipsychotics, benzodiazepines Previous or current neurological, musculoskeletal, rheumatic, malignant, inflammatory or mental illnesses Current or prior chronic pain conditions Lack of ability to cooperate

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Active tDCS<br> | Device: Active tDCS<br>* Using the 2-channel neuro-stimulator Sooma tDCS equipment we provide 20 minutes of 2 mA anodal stimulation of the primary motor cortex (M1) with the cathode located over the right primary somatosensory cortex (S1).<br>|
| Placebo Comparator: Sham tDCS<br> | Device: Sham tDCS<br>* Using the 2-channel neuro-stimulator Sooma tDCS equipment we provide a sham stimulation with the anode place over the primary motor cortex (M1) and cathode located over the right primary somatosensory cortex (S1). The sham stimulation consists of 30 seconds of stimulation ramping up to a maximum of 2 mA, then 19 minutes of the device providing no stimulation and then ramping down from 2 mA intensity to 0 in the last 30 seconds. This configuration is designed to mimic the sensory experience of active tDCS.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pressure pain threshold | A hand-held pressure algometer (Somedic, Hörby, Sweden) with a 1-cm2 probe was used to record the pressure pain threshold. The pressure is increased gradually at a rate of 30 kPa/s. The measurement is repeated three times on descending part of the medial musculus trapezius sinister and dexter respectively. | Two assessments total: Once before the stimulation intervention (baseline assessment) and once again three minutes after the stimulation (post intervention assessment). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Heat and Cold Pain Detection Thresholds | A 3×3 cm (9 cm2) contact thermode (Medoc Advanced Medical Systems, Israel) was used to apply thermal stimulation. Each stimulus will be started at 32°C and thresholds of heat and cold pain detection was assessed by ascending or descending ramps in temperature to the cutoffs of 0-50 °C. This will be assessed on the skin over the left side descending part of the medial musculus trapezius. | Two assessments total: Once before the stimulation intervention (baseline) and once again five minutes after the stimulation (post intervention assessment). |