Effects of Transcranial Direct Current Stimulation (tDCS) and Visual Illusion on Chronic Pain Due to Spinal Cord Injury


The purpose of this study is to investigate the effects of Transcranial Direct Current Stimulation (tDCS) combined with watching a visual illusion on chronic pain due to spinal cord injury. The investigators hypothesize that active tDCS will reduce pain in subjects with spinal cord injury when compared to sham stimulation. The investigators will also measure changes in EEG data (alpha and beta frequencies) as well as motor cortex excitability.

Full Title of Study: “Investigation of the Mechanisms of Transcranial Direct Current Stimulation of Motor Cortex Coupled With Visual Illusion for the Treatment of Chronic Pain in Spinal Cord Injury”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Double (Participant, Investigator)
  • Study Primary Completion Date: August 2014


  • Procedure: Transcranial Direct Current Stimulation (tDCS)
    • Subjects will undergo tDCS stimulation. For both active and sham stimulation, we will use electrodes of 35cm^2, at an intensity of 2mA. For active tDCS, the subject will undergo stimulation for 20 minutes. For sham stimulation, the current will be ramped up and then down again (for 30 seconds total) to simulate the feeling of active stimulation.

Arms, Groups and Cohorts

  • Experimental: Active tDCS + visual illusion
    • Subjects will receive active tDCS while watching a visual illusion movie (legs walking on a treadmill). Stimulation will last for 20 minutes.
  • Sham Comparator: Sham tDCS + visual illusion
    • Subjects will receive sham tDCS stimulation (30 seconds ramp up/ramp down) while watching a visual illusion movie (legs walking on a treadmill)
  • Other: Healthy Subjects
    • Healthy subjects will receive both interventions (active and sham) in a randomized and counterbalanced order. Each stimulation session will be at least 1 week apart to prevent carry-over effects

Clinical Trial Outcome Measures

Primary Measures

  • Changes in EEG (alpha and beta activity)
    • Time Frame: Measured for approximately 6 weeks
    • Determine whether treatment with tDCS coupled with visual illusion change cortical activity as assessed with electroencephalography (EEG). We hypothesize that tDCS plus visual illusion increase in alpha activity and inhibit beta activity and this will be associated with pain reduction in patients with moderate to severe below-level spinal cord injury (SCI) pain. EEG measurements will take place throughout the subject’s participation in the study, measured at: baseline, immediately pre- and post- stimulation and at follow-up visits for a total of approximately 6 weeks.

Secondary Measures

  • Changes in cortical excitability
    • Time Frame: Measured for approximately 6 weeks
    • To investigate whether active tDCS combined with visual illusion induces changes in motor cortex and as indexed by single and paired-pulse transcranial magnetic stimulation (TMS) as compared with sham tDCS coupled with visual illusion. We will also determine whether these changes are correlated with the clinical outcome (pain reduction). TMS measurements will take place throughout the subject’s participation in the study, measured at: baseline, immediately pre- and post- stimulation and at follow-up visits for a total of approximately 6 weeks.

Participating in This Clinical Trial


Inclusion Criteria

1. Providing informed consent to participate in the study

2. 18 to 64 years old

3. With traumatic spinal cord injury (complete or incomplete) – for instance, due to fall, car accident or gun shot; (for spinal cord injury only)

4. Stable chronic pain for at least the three preceding months (for spinal cord injury only)

5. Score higher or equal to 4cm (0 cm= 'no pain' and 10cm='worst possible pain') on the Visual Analogue Scale (VAS) for pain perception at the baseline/start of the treatment (for spinal cord injury only)

6. Refractoriness to drugs for pain relief – such as tricyclic antidepressants, antiepileptic drugs and/or narcotics (pain resistant to at least 2 of these drugs supplied in adequate dosages for six months) (for spinal cord injury only)

7. Pain is not attributable to other causes, such as peripheral inflammation

Exclusion Criteria

1. Clinically significant or unstable medical or psychiatric disorder

2. History of substance abuse

3. Neuropsychiatric comorbidities, including: Documented traumatic brain injury (TBI), defined as damage to brain tissue caused by an external mechanical force as evidenced by: loss of consciousness due to brain trauma, or post traumatic amnesia (PTA), or skull fracture, or objective neurological findings that can be reasonably attributed to TBI as assessed by the study PI

4. Implanted devices for pain control, such as vagal or deep brain stimulators

5. Contraindications to tDCS:

  • metal in the head
  • implanted brain medical devices

6. Pregnancy

7. Use of ventilators or ventilation support

8. Complete tetraplegic lesion (no motor function in the arms) (C3 to C8) as we will be measuring the motor evoked potential in the FDI (upper limbs); only tetraplegic patients with incomplete functional status and also as defined by the ability to elicit MEP in the FDI will be able to participate in this study

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 64 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Spaulding Rehabilitation Hospital
  • Provider of Information About this Clinical Study
    • Principal Investigator: Felipe Fregni, Principal Investigator – Spaulding Rehabilitation Hospital
  • Overall Official(s)
    • Felipe Fregni, MD, PhD, MPH, Principal Investigator, Spaulding Rehabilitation Hospital (SRH)

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