Effectiveness of transcranial direct current stimulation and visual illusion on neuropathic pain in spinal cord injury

Abstract

The aim of this study was to evaluate the analgesic effect of transcranial direct current stimulation of the motor cortex and techniques of visual illusion, applied isolated or combined, in patients with neuropathic pain following spinal cord injury. In a sham controlled, double-blind, parallel group design, 39 patients were randomized into four groups receiving transcranial direct current stimulation with walking visual illusion or with control illusion and sham stimulation with visual illusion or with control illusion. For transcranial direct current stimulation, the anode was placed over the primary motor cortex. Each patient received ten treatment sessions during two consecutive weeks. Clinical assessment was performed before, after the last day of treatment, after 2 and 4 weeks follow-up and after 12 weeks. Clinical assessment included overall pain intensity perception, Neuropathic Pain Symptom Inventory and Brief Pain Inventory. The combination of transcranial direct current stimulation and visual illusion reduced the intensity of neuropathic pain significantly more than any of the single interventions. Patients receiving transcranial direct current stimulation and visual illusion experienced a significant improvement in all pain subtypes, while patients in the transcranial direct current stimulation group showed improvement in continuous and paroxysmal pain, and those in the visual illusion group improved only in continuous pain and dysaesthesias. At 12 weeks after treatment, the combined treatment group still presented significant improvement on the overall pain intensity perception, whereas no improvements were reported in the other three groups. Our results demonstrate that transcranial direct current stimulation and visual illusion can be effective in the management of neuropathic pain following spinal cord injury, with minimal side effects and with good tolerability.

Delayed pain decrease following M1 tDCS in spinal cord injury: A randomized controlled clinical trial

“…In a previous study, our group has tested the effects of tDCS in SCI patients suffering from neuropathic pain, showing that 5 sessions of M1 tDCS significantly reduced level of pain after the end of the stimulation sessions but not when reassessed at 2-week follow-up [7]. Other studies, investigating the neural correlates of tDCS in SCI, or the combination of tDCS with adjuvant therapy, have found similar results on pain intensity reduction following the stimulation of M1 [17][18][19][20].…”

“…The authors explained that lack of effects is likely due to refractoriness of pain and duration of disease since most of the patients enrolled had injury durations of 10 or more years. In addition, the limited number of [19][20][21][22][23][24][25][26] sessions and small sample size, may not have been sufficient to observe significant effects at follow-up. The second study, on low back pain, even though the sample size was large (n = 135), did not show significant differences between sham and active tDCS [58].…”

“…This observation highlights the long-term effects of tDCS in maintaining low level of pain as compared to the sham intervention. As abovementioned, several studies have highlighted the need for repeating the number of tDCS sessions (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) to induce long-lasting and clinically relevant effects. In the present study, even with a limited sample size, we demonstrated that adding a second phase of 10 stimulations sessions can help maintaining the benefits induced by tDCS.…”

Virtual feedback for motor and pain rehabilitation after spinal cord injury

“…VF interventions and assessments were focused on improving motor functions in patients that were pain-free (or in whom pain was not reported; n = 12) 1,2,12-21 or on reducing pain in patients with different levels of motor dysfunction and neuropathic pain (n = 4). 4,5,22,23 Only one study explicitly assessed the effects of a VF intervention on both motor dysfunctions and neuropathic pain. 6 VF modalities and tasks Improving motor functions.…”

“…VF uses virtual reality displayed on large screens or on head-mounted displays to provide patients with interactive, multimodal sensory stimuli and biofeedback, and may be applied alone or in combination with physical or cognitive interventions. For example, 'virtual walking', offering an illusion of normal gait, may improve motor functions 1,2 and may reduce neuropathic pain [3][4][5] after spinal cord injury (SCI).…”