Paired Acute Invasive/Non-invasive Stimulation Trial

Study Overview
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Brief Summary
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Chronic pain patients with implanted dorsal root ganglion stimulators will be randomized to receive transcranial direct current stimulation (tDCS) to the motor cortex, magneto-encephalographically (MEG) localized stimulation or sham stimulation to identify therapeutic efficacy of paired central and peripheral neuromodulation.

Official Title
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Paired Transcranial Direct Current Stimulation/ Dorsal Root Ganglion Stimulation Trial

Conditions
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Chronic Pain

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: Patients who are willing and able to give consent to the study. Male or Female, aged 18 years or above with diagnoses of chronic pain. Treatment includes Spinal Cord Stimulation, Dorsal Root Ganglion stimulation, or peripheral analgesic stimulation. Exclusion Criteria: Patients who do not wish to be in the study. Patients with metallic intracranial implants. Patients with extreme language barrier that cannot understand the purpose of the study despite the use of an interpreter

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: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Sham stimulation<br> | Device: Transcranial direct current stimulation<br>* tDCS produces hyper/hypopolarizing potentials in the cortex underlying the scalp electrodes and can increase/decrease the excitability of targeted brain regions.<br>* Other names: tDCS;|
| Active Comparator: Motor cortex stimulation<br> | Device: Transcranial direct current stimulation<br>* tDCS produces hyper/hypopolarizing potentials in the cortex underlying the scalp electrodes and can increase/decrease the excitability of targeted brain regions.<br>* Other names: tDCS;|
| Experimental: MEG-localized stimulation<br> | Device: Transcranial direct current stimulation<br>* tDCS produces hyper/hypopolarizing potentials in the cortex underlying the scalp electrodes and can increase/decrease the excitability of targeted brain regions.<br>* Other names: tDCS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in pain scores: 21-point pain scale rating | 21-point pain scale rating | Immediately after 30 minutes of transcranial direct current stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in EEG recordings | Changes in electrical fields of the cortex | Immediately after 30 minutes of transcranial direct current stimulation | 
| Changes in Facial Expression Recognition Performance | An emotional categorisation task to identify anti-depressant effects | Immediately after 30 minutes of transcranial direct current stimulation |