Effects of rTMS and tDCS on neuropathic pain after brachial plexus injury: a randomized placebo-controlled pilot study

Abstract

Neuropathic pain after brachial plexus injury (NPBPI) is a highly disabling clinical condition and is increasingly prevalent due to increased motorcycle accidents. Currently, no randomized controlled trials have evaluated the effectiveness of non-invasive brain stimulation techniques such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS) in patients suffering from NPBPI. In this study, we directly compare the efficacy of 10-Hz rTMS and anodal 2 mA tDCS techniques applied over the motor cortex (5 daily consecutive sessions) in 20 patients with NPBPI, allocated into 2 parallel groups (active or sham). The order of the sessions was randomised for each of these treatment groups according to a crossover design and separated by a 30-day interval. Scores for “continuous” and “paroxysmal” pain (primary outcome) were tabulated after the last stimulation day and 30 days after. Secondary outcomes included the improvement in multidimensional aspects of pain, anxiety state and quality of life from a qualitative and quantitative approach. Active rTMS and tDCS were both superior to sham in reducing continuous (p < 0.001) and paroxysmal (p = 0.002; p = 0.02) pain as well as in multidimensional aspects of pain (p = 0.001; p = 0.002) and anxiety state (p = < 0.001; p = 0.005). Our results suggest rTMS and tDCS are able to treat NPBPI with little distinction in pain and anxiety state, which may promote the use of tDCS in brachial plexus injury pain management, as it constitutes an easier and more available technique.Clinical Trial Registration: http://www.ensaiosclinicos.gov.br/, RBR-5xnjbc – Sep 3, 2018.

Better Fields or Currents? A Head-to-Head Comparison of Transcranial Magnetic (rTMS) Versus Direct Current Stimulation (tDCS) for Neuropathic Pain

“…In support of this view, a lack of effect of tDCS has been described in patients previously responding to rTMS [38], and conversely a patient with chronic NP not responding to rTMS could be improved in the long term by anodal tDCS [39]. A very recent report comparing these two techniques in 12 patients with brachial plexus avulsion also found that different patients may be differentially sensitive to one or the other [24]. Together with these previous reports, the present study in a larger sample of NP patients appears clinically relevant in that it highlights the possibility of using one technique if the other fails, thereby increasing the probability of a positive response, which currently tops out at about 50% for rTMS [2,3,14].…”

“…One single study comparing the short-term effect of 3 sessions of anodal tDCS versus HF-rTMS in lumbosacral radiculopathy concluded to the superiority of rTMS [23], while a very recent report in 12 patients with brachial plexus injuries found similar results from both techniques [24]. Head-tohead studies directly comparing the efficacy of HF-rTMS and a-tDCS for chronic, drug-resistant NP in large patients' series are therefore warranted.…”

Repetitive Transcranial Magnetic Stimulation of the Primary Motor Cortex beyond Motor Rehabilitation: A Review of the Current Evidence

“…On the other hand, three individual studies reported a significant analgesic efficacy for at least one month after 10 sessions of M1-rTMS in patients with failed back surgery syndrome [ 78 ] and chronic central pain after traumatic brain injury [ 79 ], and after 5 sessions in patients with traumatic brachial plexus injury [ 80 ].…”

The Safety and Feasibility of Transcranial Direct Current Stimulation Combined with Conservative Treatment for Cervicogenic Headaches: A double-blinded randomized control study

“…M1 was chosen as the treatment target based on positive results in previous migraine and chronic pain tDCS literature. 28,31,36 Furthermore, previous literature has proposed that M1 stimulation leads to pain reduction through engagement of the descending pain modulatory network, through reduced connectivity between the thalamus and prefrontal pain centers, and through residual stimulation of the somatosensory cortex which is also involved in pain sensation. 27 Finally, stimulating M1 in combination with exercise therapy may result in improved motor learning and response to exercise therapy which will indirectly lead to pain reduction.…”

“…26,27 Furthermore, several tDCS studies have explored tDCS over the M1 as a treatment for chronic pain conditions. [30][31][32][33] Recently, Yeh et al and Bonifácio de Assis et al noted signi cant reductions in pain intensity for participants with neuropathic pain following tDCS therapy. 30,31 Despite promising results for the use of tDCS in treating chronic pain and primary headaches, no studies have evaluated tDCS for the treatment of people with CGH.…”