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

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

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.

STUDY ELIGIBILITY CRITERIA

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