Transcranial direct current stimulation in the modulation of neuropathic pain: a systematic review

Abstract

Objective To investigate the neuromodulating effect of Transcranial Direct Current Stimulation (tDCS) on Neuropathic Pain (NP). Method A systematic review of articles published in the past five years in MEDLINE, LILACS, Cochrane, Scopus, ScienceDirect, and PEDro. The search was carried out from February to May 2017 using the keywords: neuropathic pain, neuralgia, nerve pain, central pain, peripheral nerve pain, tDCS. The selected studies were full articles written in Portuguese, English, or Spanish with at least one control group, and no less than one pre- or post-intervention variable, with the exclusion of case studies or case series, animal model studies, and studies with combined therapy. The quality of the selected articles was evaluated through PEDro scale, whereas the level of agreement among reviewers was measured with the Cohen's κ test, considering P < 0.05 to be significant. Results Eight articles were selected (PEDro: 8.5 ± 0.6; Cohen's κ test: 0.703, P < 0.01), six of which were randomized controlled trials and two were controlled clinical trials. The following causes of NP were observed: spinal cord injury (SCI), amputation, stroke, multiple sclerosis (MS), and radiculopathy. All of the studies showed significant effects of tDCS on NP when compared to the control group, except for one with SCI and another related to radiculopathy. Discussion The shortage of good quality articles, the varying of ramp-on and ramp-off durations, and number of sessions, as well as the diversity of results found did not allow any definite conclusion on the efficacy of the neuromodulating effect of tDCS on NP.

<p>Combining Transcranial Direct Current Stimulation and Transcutaneous Electrical Nerve Stimulation to Relieve Persistent Pain in a Patient Suffering from Complex Regional Pain Syndrome: A Case Report</p>

“…Past studies have suggested that the hypoalgesic effect of tDCS and TENS could be cumulative, with individuals reporting greater pain relief with increasing number of sessions. 21,50 Although we cannot rule out a cumulative effect of tDCS, the results obtained following the second tDCS+TENS intervention (Treatment C, given 6 months later) somewhat argues in favor of a more potent effect of the combination of treatments, although both mechanisms could be simultaneously involved. The number of tDCS +TENS sessions required to optimally relieve pain is still unknown, but our observations could suggest that increasing the number of tDCS/TENS treatments could possibly lead to greater effects.…”

“…The number of tDCS +TENS sessions required to optimally relieve pain is still unknown, but our observations could suggest that increasing the number of tDCS/TENS treatments could possibly lead to greater effects. 21 The higher pain level noted during the pretreatment period of Treatment C could also have influenced our results. Still, the difference between the pretreatment pain intensity (Pre-Tx) of logbook 1 and logbook 2 are not clinically significant.…”

“…5,[16][17][18][19] Although not fully understood, analgesic effects of tDCS are thought to be driven by cortical excitability modulation, and possibly by endogenous μ-opioids release when applied over the motor cortex. [20][21][22][23][24] Another interesting non-pharmacological approach used in pain rehabilitation is transcutaneous electrical nerve stimulation (TENS). [25][26][27] Low-frequency TENS (<10 Hz) activates descending pain inhibition systems (conditioned pain modulation [CPM]) and promotes the release of endogenous opioid mechanisms that can markedly reduce pain symptoms.…”

Intramuscular electrical stimulus potentiates the motor cortex modulation effects on pain and descending inhibitory systems in knee osteoarthritis: a randomized, factorial, sham-controlled study

“…Hence, tDCS is a promising technique because it modulates the thalamocortical synapses in a top-down manner within pain pathways7 and it might change in thalamic inhibitory pathways, cingulate cortex, and periaqueductal gray matter induced by tDCS 8–106 and chronic pain (eg, trigeminal neuralgia, phantom pain, and fibromyalgia) 11…”

Update on the Use of Transcranial Electrical Brain Stimulation to Manage Acute and Chronic COVID-19 Symptoms

“…Neuromodulation, which spans a broad range of implanted and non-invasive modalities, may have a potential role in the treatment of COVID-19 related symptoms. This potential is theorized based on the known mechanisms of biological action, demonstrated benefits in non-COVID-19 patients for various known sequelae of COVID-19 illness and recovery (Lefaucheur et al, 2017;David et al, 2018;Ghosh, 2019;Razza et al, 2020), with initial reports of its application in COVID-19 patients (Azabou et al, 2020;Bonaz et al, 2020;Kaniusas et al, 2020;Shinjo et al, 2020;Zhang et al, 2020).…”