Predicting Pain Response to Transcranial Direct Current Stimulation for Phantom Limb Pain in Limb Amputees

Study Overview
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Brief Summary
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This study explores the effects transcranial Direct Current Stimulation (tDCS, Soterix ©) on Phantom Limb Pain for patients experiencing chronic phantom limb pain in open-label study design.

Official Title
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Predicting Pain Response to Transcranial Direct Current Stimulation for Phantom Limb Pain in Limb Amputees

Conditions
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Phantom Limb Pain

Intervention / Treatment
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* Device: transcranial Direct Current Stimulation (tDCS): (Soterix ©)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Able to provide informed consent to participate in the study. Subject is older than 18 years. 3 months of phantom limb pain (experienced regularly for at least once a week) after the amputated limb has completely healed. Average pain of at least 4 on a numeric rating scale in the previous week (NRS; ranging from 0 to 10). If the subject is taking any medications, dosages must be stable for at least 2 weeks prior to the enrollment of the study. Exclusion Criteria: Pregnancy or trying to become pregnant in the next 2 months. History of alcohol or drug abuse within the past 6 months as self-reported. Presence of the following contraindication to transcranial direct current stimulation Ferromagnetic metal in the head (e.g., plates or pins, bullets, shrapnel) Implanted head electronic medical devices (e.g., cochlear implants) Head injury resulting in loss of consciousness for at least 30 min or pos-traumatic amnesia for greater than 24 hours, as self-reported Unstable medical conditions (e.g. uncontrolled diabetes, uncompensated cardiac issues, heart failure or chronic obstructive pulmonary disease). Uncontrolled Epilepsy Suffering from severe depression (as defined by a score of >30 in the Beck Depression Inventory).* History of unexplained fainting spells or loss of consciousness as self-reported during the last 2 years. History of neurosurgery, as self-reported.

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: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: tDCS intervention (open label)<br>Subjects will undergo tDCS stimulation | Device: transcranial Direct Current Stimulation (tDCS): (Soterix ©)<br>* Subjects will undergo tDCS stimulation. We will use electrodes of 35cm^2, at an intensity of 2mA on the primary motor cortex contralateral to the amputated limb (or for bilateral amputees contralateral to the most painful side). The subject will undergo stimulation for 20 minutes. The subject will have 5 sessions of stimulation during a 1 week time period.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain as Measured by the Visual Analog Scale | The VAS is a common assessment used which asks subjects to self-reportedly measure their pain on a visual scale (i.e., unbearable to none). We will use a VAS to determine subjects' pain scores. Subjects will rate their pain from 0 - indicating no pain at all, to 10 - indicating the worst pain felt. This scale is also colored, from green (at 0) to red (at 10), as a visual indicator of pain. | Change in outcome from baseline to 2-week follow-up (after the last day of stimulation) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Limb amputation, phantom limb pain, maladaptive plasticity, tDCS, non-invasive brain stimulation