Transcranial Direct Current Stimulation and Mirror Therapy for Neuropathic Pain After Brachial Plexus Avulsion: A Randomized, Double-Blind, Controlled Pilot Study

Abstract

Introduction: Although transcranial direct current stimulation (tDCS) and mirror therapy (MT) have benefits in combating chronic pain, there is still no evidence of the effects of the simultaneous application of these techniques in patients with neuropathic pain. This study aims to assess the efficacy of tDCS paired with MT in neuropathic pain after brachial plexus injury.Methods: In a sham controlled, double-blind, parallel-group design, 16 patients were randomized to receive active or sham tDCS administered during mirror therapy. Each patient received 12 treatment sessions, 30 min each, during a period of 4 weeks over M1 contralateral to the side of the injury. Outcome variables were evaluated at baseline and post-treatment using the McGill questionnaire, Brief Pain Inventory, and Medical Outcomes Study 36–Item Short-Form Health Survey. Long-term effects of treatment were evaluated at a 3-month follow-up.Results: An improvement in pain relief and quality of life were observed in both groups (p ≤ 0.05). However, active tDCS and mirror therapy resulted in greater improvements after the endpoint (p ≤ 0.02). No statistically significant differences in the outcome measures were identified among the groups at follow-up (p ≥ 0.12). A significant relationship was found between baseline pain intensity and outcome measures (p ≤ 0.04). Moreover, the results showed that state anxiety is closely linked to post-treatment pain relief (p ≤ 0.05).Conclusion: Active tDCS combined with mirror therapy has a short-term effect of pain relief, however, levels of pain and anxiety at the baseline should be considered.Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT04385030.

Pain reduction in fibromyalgia syndrome through pairing transcranial direct current stimulation and mindfulness meditation: A randomized, double-blinded, sham-controlled pilot clinical trial

“…FMS patients receiving an intervention of active tDCS combined with concurrent aerobic exercise reported decreased pain intensity and anxiety levels compared to those in the sham group ( 76 ). Similar therapeutic effects have been observed by combining strengthening exercise with tDCS in knee osteoarthritis ( 77 ) or adding tDCS to mirror therapy in neuropathic pain patients ( 78 ). Despite the above evidence for larger improvement of symptoms in chronic pain during active tDCS than sham, we did not observe any larger reduction in pain intensity and associated symptoms in the active + MM group, compared to the sham + MM and NoT groups.…”

Time since onset might be of essence: A recommendation to assess the effects of combination of non-pharmacological neuromodulatory approaches at early stage since symptoms onset

“…In all studies, the tDCS intensity was set to 2mA, except for Segal et al ( 12 ), which used 1.5 mA. In all the studies, the tDCS duration was 20 min, except in Ferreira et al ( 15 ), which used 30 min per session. The duration of the non-pharmacological neuromodulatory approaches ranged from 12 to 20 min, except for Ferreira et al ( 15 ), which used 30 minutes per session.…”

“…To address this hypothesis, researchers began to explore the analgesic effects of such combined treatments in various pain indications, including phantom limb pain ( 12 – 14 ), neuropathic pain ( 15 – 23 ), complex regional pain syndrome ( 24 , 25 ), fibromyalgia ( 26 – 33 ), headache ( 34 ), chronic musculoskeletal pain ( 35 ), chronic low-back pain ( 36 – 40 ), knee osteoarthritis pain ( 41 – 45 ), temporomandibular disorders ( 46 ), burning mouth syndrome ( 47 ), chronic visceral pain ( 48 ), neurogenic pain ( 49 ), myofascial pain ( 50 , 51 ), tendinopathy ( 52 ), and radiculopathy ( 53 ) ( Table 1 ).…”

“…The other neuromodulatory approaches that were combined with the tDCS could be grouped into 4 categories: The first category includes mirror therapy ( 12 – 15 ), visual illusion ( 16 – 18 , 22 ) and motor graded imagery ( 24 ). These three interventions are sharing similar characteristic—in all these behavioral tasks the participants receive (or imagine) visual input (with, or without additional sensory-motor input) that is assumed to counterbalance the maladaptive plasticity associated with the painful condition.…”

Brain stimulation: a therapeutic approach for the treatment of neurological disorders

“…Studies have shown that a treatment with tDCS on the M1 area causes long‐lasting relief in medication‐resistant patients with chronic pain syndrome such as trigeminal neuralgia, post‐stroke pain, back pain, and fibromyalgia 108,109 . The efficacy of tDCS in alleviating pain has also been shown in patients with multiple sclerosis joint pain, 110 neuropathic pain, 111 spinal cord injury, 112 fibromyalgia, 113 chronic migraine, 114 foot pain, 115 and intra‐abdominal pain 116 . A meta‐analysis studies further found that a treatment with tDCS reduces chronic pain intensity 47 …”