Repetitive transcranial magnetic stimulation increases the corticospinal inhibition and the brain-derived neurotrophic factor in chronic myofascial pain syndrome: an explanatory double-blinded, randomized, sham-controlled trial

Modulating neuroplasticity for chronic pain relief: noninvasive neuromodulation as a promising approach

Chronic neuropathic pain is a debilitating neuroplastic disorder that notably impacts the quality of life of millions of people worldwide. This complex condition, encompassing various manifestations, such as sciatica, diabetic neuropathy and postherpetic neuralgia, arises from nerve damage or malfunctions in pain processing pathways and involves various biological, physiological and psychological processes. Maladaptive neuroplasticity, known as central sensitization, plays a critical role in the persistence of chronic neuropathic pain. Current treatments for neuropathic pain include pharmacological interventions (for example, antidepressants and anticonvulsants), invasive procedures (for example, deep brain stimulation) and physical therapies. However, these approaches often have limitations and potential side effects. In light of these challenges, interest in noninvasive neuromodulation techniques as alternatives or complementary treatments for neuropathic pain is increasing. These methods aim to induce analgesia while reversing maladaptive plastic changes, offering potential advantages over conventional pharmacological practices and invasive methods. Recent technological advancements have spurred the exploration of noninvasive neuromodulation therapies, such as repetitive transcranial magnetic stimulation, transcranial direct current stimulation and transcranial ultrasound stimulation, as well as innovative transformations of invasive techniques into noninvasive methods at both the preclinical and clinical levels. Here this review aims to critically examine the mechanisms of maladaptive neuroplasticity in chronic neuropathic pain and evaluate the efficacy of noninvasive neuromodulation techniques in pain relief. By focusing on optimizing these techniques, we can better assess their short-term and long-term effects, refine treatment variables and ultimately improve the quality of neuropathic pain management.

Age-related differences in agility are related to both muscle strength and corticospinal tract function

Agility is essential for "healthy" aging, but neuromuscular contributions to age-related differences in agility are not entirely understood. We recruited healthy (n = 32) non-athletes (30-84 years) to determine: (1) if aging is associated with agility and (2) whether muscle strength or corticospinal tract function predicts agility. We assessed muscle strength via a validated knee extension test, corticospinal tract function via transcranial magnetic stimulation, and agility via spatiotemporal values (i.e., leg length-adjusted hop length and hop length variability) collected during a novel propulsive bipedal hopping (agility) task on an electronic walkway. Pearson correlation revealed aging is associated with leg length-adjusted hop length (r = -0.671, p < 0.001) and hop length variability (r = 0.423, p = 0.016). Further, leg length-adjusted hop length and hop length variability correlated with quadriceps strength (r = 0.581, p < 0.001; r = -0.364, p = 0.048) and corticospinal tract function (r = -0.384, p = 0.039; r = 0.478, p = 0.007). However, hierarchical regressions indicated that, when controlling for sex, muscle strength only predicts leg length-adjusted hop length (R2 = 0.345, p = 0.002), whereas corticospinal tract function only predicts hop length variability (R2 = 0.239, p = 0.014). Therefore, weaker quadriceps decrease the distance hopped, and deteriorating corticospinal tract function increases variability in hop length.

Efficacy of manual lymphatic drainage combined with repetitive transcranial magnetic stimulation in post-stroke complex regional pain syndrome: a pilot study

PURPOSE

The aim of this study was to investigate the efficacy of manual lymphatic drainage (MLD) combined with repetitive transcranial magnetic stimulation (rTMS) on the recovery of upper limb in patients with post-stroke complex regional pain syndrome (CRPS).

METHODS

This pilot study was conducted with 54 patients with post-stroke CRPS. Patients were randomized into three groups: the MLD combined with rTMS group (MLD + rTMS group), the rTMS group and the sham-rTMS group. The results of numeric rating scale (NRS), volumetric measurement, Fugl-Meyer assessment of upper extremity (FMA-UE), CRPS severity score (CSS), generalized anxiety disorder-7 (GAD-7) and patient health questionnaire-9 (PHQ-9) before and after the intervention were analyzed.

RESULTS

Fifty-four participants (37 males, 17 females; mean age 66.11 ± 8.43 years; range, 18 to 85) were included in the study. Among groups, improvements were statistically significant with superiority of rTMS + MLD group after treatment (p < 0.05). NRS, GAD-7, and PHQ-9 in the rTMS + MLD group improved more significantly than those in the rTMS group (p < 0.05).

CONCLUSION

MLD combined with rTMS has an add-on efficacy on the basis of rTMS therapy in post-stroke patients, especially in pain. MLD could also have an effect on anxiety and depression.

Repetitive transcranial magnetic stimulation in central post-stroke pain: a meta-analysis and systematic review of randomized controlled trials

Background

The rehabilitation of central post-stroke pain (CPSP) is a complex clinical challenge, and repetitive transcranial magnetic stimulation (rTMS) has been widely applied in the research of neurofunctional recovery following stroke. However, there is currently no reliable evidence-based medicine supporting the efficacy of rTMS in central post-stroke pain. This review aims to evaluate the effects of rTMS on central post-stroke pain.

Methods

Following the PRISMA guidelines, we conducted searches on PubMed, Cochrane Library, Embase, Web of Science, CNKI, and Wan Fang Data Knowledge Service Platform. We searched for randomized controlled trials (RCTs) investigating the use of rTMS in treating central post-stroke pain, and conducted screening based on inclusion and exclusion criteria. Characteristics of the included RCTs were extracted. The heterogeneity of the trials was assessed using the I2 statistic. Meta-analysis was performed using Stata 17 software. Bias risk and methodological quality were evaluated using the Cochrane RoB 2 tool and the Pedro scale.

Results

A total of six randomized controlled trials involving 288 patients met our inclusion criteria. In our analysis, rTMS was more effective in treating patients with CPSP compared to the placebo group (SMD=-1.15, 95% CI: -1.69, -0.61, P < 0.001). Furthermore, results from subgroup analysis indicated no statistically significant difference in the improvement of pain for durations exceeding 6 months when comparing rTMS to conventional treatment (SMD=-0.80, 95% CI: -1.63, 0.03, P = 0.059).

Conclusion

TMS can alleviate pain in CPSP patients and improve their motor function, but its effects on depression, anxiety, and MEP-latency are not significant.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, CRD42024497530.

The efficacy of repetitive transcranial magnetic stimulation in postherpetic neuralgia: a meta-analysis of randomized controlled trials

Purpose

This systematic review and meta-analysis aimed to evaluate the efficacy of repetitive transcranial magnetic stimulation (rTMS) in postherpetic neuralgia (PHN).

Methods

Through an extensive search in four databases until October 2023, we selected five randomized controlled trials adhering to our specific criteria, involving 257 patients in total. For continuous outcomes, the standardized mean difference (SMD) was calculated. Heterogeneity among the studies was assessed using Cochran's I 2 and Q statistics, adopting a random-effects model for I 2 values over 50%. For assessing potential publication bias, we utilized both funnel plot and Egger's test.

Results

Our analysis found that rTMS reduced the overall visual analogue scale (VAS) (SMD: -1.52, 95% CI: -2.81 to -0.23, p = 0.02), VAS at 1 month post-treatment (SMD: -2.21, 95% CI: -4.31 to -0.10, p = 0.04), VAS at 3 months post-treatment (SMD: -1.51, 95% CI: -2.81 to -0.22, p = 0.02), as well as patients' global impression of change scale (PGIC) (SMD: -1.48, 95% CI: -2.87 to -0.09, p = 0.04) and short-form McGill pain questionnaire (SF-MPQ) (SMD: -1.25, 95% CI: -2.41 to -0.09, p = 0.03) compared to the sham-rTMS group.

Conclusion

Our study suggests that rTMS might have a potential alleviating effect on PHN symptoms. However, due to the limited number of studies and variations in rTMS parameters, larger sample studies involving more diverse populations, as well as further clarification of the most appropriate stimulation protocol, are still needed.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, Identifier ID: CRD42023488420.

Brain-Derived Neurotrophic Factor, Nociception, and Pain

This article examines the involvement of the brain-derived neurotrophic factor (BDNF) in the control of nociception and pain. BDNF, a neurotrophin known for its essential role in neuronal survival and plasticity, has garnered significant attention for its potential implications as a modulator of synaptic transmission. This comprehensive review aims to provide insights into the multifaceted interactions between BDNF and pain pathways, encompassing both physiological and pathological pain conditions. I delve into the molecular mechanisms underlying BDNF's involvement in pain processing and discuss potential therapeutic applications of BDNF and its mimetics in managing pain. Furthermore, I highlight recent advancements and challenges in translating BDNF-related research into clinical practice.

Impact of Repetitive Transcranial Magnetic Stimulation on Cognitive and Psychiatric Dysfunction in Patients with Fibromyalgia: A Double-Blinded, Randomized Clinical Trial

Few randomized controlled trials have reported that repetitive transcranial magnetic stimulation (rTMS) has controversial results for managing multiple domains of fibromyalgia-related symptoms. This work aimed to evaluate the effect of low-frequency rTMS over the right dorsolateral prefrontal area (DLPFC) on the Fibromyalgia Impact Questionnaire (FIQ) concerning psychiatric and cognitive disorders. Forty-two eligible patients with fibromyalgia (FM) were randomized to have 20 sessions of active or sham rTMS (1 Hz, 120% of resting motor threshold with a total of 1200 pules/session) over the right DLPFC. All participants were evaluated at baseline, post sessions, and 3 months after sessions with the FIQ, Hamilton depression, and anxiety rating scales (HDRS and HARS), Montreal Cognitive Assessment (MoCA), Rey Auditory Verbal Learning Test (RAVLT), Tower of London test (TOL), the Trail Making, and Digit Span Tests. Both groups showed improvement in most rating scales at 1 and 3 months follow-up, with greater improvement in the active group, with significant correlation between FIQ cognitive rating scales, including RAVLT and TOL. Twenty sessions of low-frequency rTMS over the right DLPFC can improve FIQ scores regarding the psychiatric and cognitive symptoms of medicated patients with FM to a greater extent than sham. Changes in RAVLT and TOL correlated with changes in FIQ results.

High frequency neuronavigated repetitive transcranial magnetic stimulation in post-stroke shoulder pain: A double-blinded, randomized controlled study

OBJECTIVE

This study aimed to determine the effect of 5Hz neuronavigated repetitive transcranial magnetic stimulation (rTMS) to the affected primary motor cortex (M1) on pain, the effect of pain on activities of daily living, disability, mood, neurophysiological parameters and passive shoulder joint range of motion in patients with post-stroke shoulder pain.

DESIGN

Twenty two patients were randomized into an experimental group (rTMS, n=7) who received daily rTMS 5Hz 1000 pulses, five times/week for three weeks (15 sessions) to the affected M1 and a control group (n=11) who received sham stimulation. Outcome measures were Numeric Rating Scale (NRS), Brief Pain Inventory (BPI), Disabilities of the arm, shoulder, and hand questionnaire (Quick DASH), Hospital Depression Anxiety Scale (HADS), joint range of motion (ROM) measurements, neurophysiological parameters. Selected outcome measures were performed before treatment (T0), after the 5th session (T1) of rTMS treatment, after the 10th session (T2), after the 15th session (T3), and four weeks after the end of the treatment (T4). In the analysis of the outcomes, within-group comparisons were performed by using the Wilcoxon or Friedman test and between-group comparisons were performed by using the Mann-Whitney U test.

RESULTS

There was no statistically significant difference between and within groups in terms of change- and followup scores in the NRS measurements (p>0.05). BPI scale was found to be lower in rTMS group at T0 and T3 (p= 0.010). Quick-DASH scores at T4 were found to be significantly lower in rTMS group (p= 0.032). However, no difference was found within each group over time (p>0.05) and there was no statistical difference between the groups in terms of change scores (T3-T0 and T4-T0) (p>0.05) for BPI and Quick-DASH. In rTMS group, there was a statistically significant difference in shoulder external rotation at T3 compared to the baseline (T0) (p=0.039). However, the magnitude of external rotation change (T3-T0) with the treatment was comparable in the groups. No statistically significant change occurred in both treatment groups in other range of motion measurements.

CONCLUSION

High frequency neuronavigated rTMS to the affected M1 did not show any significant beneficial effect on pain, activities of daily living, disability, anxiety and depression, neurophysiological measurements and passive ROM over sham stimulation.

Noninvasive transcranial brain stimulation in central post-stroke pain: A systematic review

BACKGROUND

The aim of this systematic review is to analyze the efficacy of noninvasive brain stimulation (NBS) in the treatment of central post-stroke pain (CPSP).

METHODS

We included randomized controlled trials testing the efficacy of transcranial magnetic stimulation (TMS) or transcranial direct current stimulation versus placebo or other usual therapy in patients with CPSP. Articles in English, Portuguese, Spanish, Italian, and French were included. A bibliographic search was independently conducted on June 1, 2022, by two authors, using the databases MEDLINE (PubMed), Embase (Elsevier), Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, and Web of Science Core Collection. The risk of bias was assessed using the second version of the Cochrane risk of bias (RoB 2) tool and the certainty of the evidence was evaluated through Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

A total of 2,674 records were identified after removing duplicates, of which 5 eligible studies were included, involving a total of 119 patients. All five studies evaluated repetitive TMS, four of which stimulated the primary motor cortex (M1) and one stimulated the premotor/dorsolateral prefrontal cortex. Only the former one reported a significant pain reduction in the short term, while the latter one was interrupted due to a consistent lack of analgesic effect.

CONCLUSION

NBS in the M1 area seems to be effective in reducing short-term pain; however, more high-quality homogeneous studies, with long-term follow-up, are required to determine the efficacy of this treatment in CSPS.

Brain stimulation targets for chronic pain: Insights from meta-analysis, functional connectivity and literature review

Noninvasive brain stimulation (NIBS) techniques have demonstrated their potential for chronic pain management, yet their efficacy exhibits variability across studies. Refining stimulation targets and exploring additional targets offer a possible solution to this challenge. This study aimed to identify potential brain surface targets for NIBS in treating chronic pain disorders by integrating literature review, neuroimaging meta-analysis, and functional connectivity analysis on 90 chronic low back pain patients. Our results showed that the primary motor cortex (M1) (C3/C4, 10-20 EEG system) and prefrontal cortex (F3/F4/Fz) were the most used brain stimulation targets for chronic pain treatment according to the literature review. The bilateral precentral gyrus (M1), supplementary motor area, Rolandic operculum, and temporoparietal junction, were all identified as common potential NIBS targets through both a meta-analysis sourced from Neurosynth and functional connectivity analysis. This study presents a comprehensive summary of the current literature and refines the existing NIBS targets through a combination of imaging meta-analysis and functional connectivity analysis for chronic pain conditions. The derived coordinates (with integration of the international electroencephalography (EEG) 10/20 electrode placement system) within the above brain regions may further facilitate the localization of these targets for NIBS application. Our findings may have the potential to expand NIBS target selection beyond current clinical trials and improve chronic pain treatment.

Mechanisms and treatments of chronic pain after traumatic brain injury

While pain after trauma generally resolves, some trauma patients experience pain for months to years after injury. An example, relevant to both combat and civilian settings, is chronic pain after traumatic brain injury (TBI). Headache as well as pain in the back and extremities are common locations for TBI-related chronic pain to be experienced. TBI-related pain can exist alone or can exacerbate pain from other injuries long after healing has occurred. Consequences of chronic pain in these settings include increased suffering, higher levels of disability, serious emotional problems, and worsened cognitive deficits. The current review will examine recent evidence regarding dysfunction of endogenous pain modulatory mechanisms, neuroplastic changes in the trigeminal circuitry and alterations in spinal nociceptive processing as contributors to TBI-related chronic pain. Key pain modulatory centers including the locus coeruleus, periaqueductal grey matter, and rostroventromedial medulla are vulnerable to TBI. Both the rationales and existing evidence for the use of monoamine reuptake inhibitors, CGRP antagonists, CXCR2 chemokine receptor antagonists, and interventional therapies will be presented. While consensus guidelines for the management of chronic post-traumatic TBI-related pain are lacking, several approaches to this clinically challenging situation deserve focused evaluation and may prove to be viable therapeutic options.

Repetitive transcranial magnetic stimulation for chemotherapy-induced peripheral neuropathy in multiple myeloma: A pilot study

Objective

Chemotherapy-induced peripheral neuropathy is one of the major toxicities in multiple myeloma patients, often resulting in dose reductions or treatment interruptions. Repetitive transcranial magnetic stimulation is a safe non-invasive neuromodulation therapy with potential benefits for chemotherapy-induced peripheral neuropathy. The objective of this study was to investigate the efficacy of repetitive transcranial magnetic stimulation treatment on chemotherapy-induced peripheral neuropathy in multiple myeloma patients.

Materials and methods

We screened 30 multiple myeloma patients with chemotherapy-induced peripheral neuropathy who underwent repetitive transcranial magnetic stimulation treatment in this study. Prior to and following repetitive transcranial magnetic stimulation treatment, patients were assessed with nerve conduction velocity, visual analog scale and the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale (EORTC QLQ-CIPN20). Categorical and continuous variables were analyzed using Fisher's exact test and Mann-Whitney U test respectively. A p-value < 0.05 (2-tailed) was considered statistically significant.

Results

Following repetitive transcranial magnetic stimulation treatment, 24/30 (80.0%) patients reported a reduction in chemotherapy-induced peripheral neuropathy symptoms. Meanwhile, all 15 patients with grade 2 chemotherapy-induced peripheral neuropathy experienced improvements about themselves, compared to 8/10 patient with grade 3 chemotherapy-induced peripheral neuropathy and 1/5 with grade 4 chemotherapy-induced peripheral neuropathy. Visual analog scale scores decreased after repetitive transcranial magnetic stimulation treatment (5.40 ± 1.94 vs 3.10 ± 1.60, p < 0.001). We also observed enhancements in both motor conduction velocity and sensory conduction velocity of patients in bilateral median nerves, posterior tibial nerves, common ulnar nerves and peroneal nerves following repetitive transcranial magnetic stimulation treatment. Analysis of the European Organization of Research and Treatment of Cancer Quality of Life Questionnaire-CIPN 20-item scale data (17.68 ± 8.14 vs 10.50 ± 9.55, p < 0.001) revealed significant reductions in scores. Patients with grade 2-3 (n = 25) exhibited a mean reduction of 8.89 ± 4.24 points, while those with grade 4 (n = 5) showed a difference value of 3.54 ± 3.45, p < 0.001. No adverse events were observed.

Conclusion

Our findings suggest that repetitive transcranial magnetic stimulation is a safe and effective therapeutic approach for ameliorating peripheral nerve injury and alleviating the chemotherapy-induced peripheral neuropathy symptoms in multiple myeloma patients. Early initiation of repetitive transcranial magnetic stimulation treatment may yield more favorable outcomes for these patients.

Non-invasive brain stimulation for fibromyalgia: current trends and future perspectives

Fibromyalgia, a common and enduring pain disorder, ranks as the second most prevalent rheumatic disease after osteoarthritis. Recent years have witnessed successful treatment using non-invasive brain stimulation. Transcranial magnetic stimulation, transcranial direct current stimulation, and electroconvulsion therapy have shown promise in treating chronic pain. This article reviews the literature concerning non-invasive stimulation for fibromyalgia treatment, its mechanisms, and establishes a scientific basis for rehabilitation, and discusses the future directions for research and development prospects of these techniques are discussed.

Novel role for non-invasive neuromodulation techniques in central respiratory dysfunction

Respiration is a crucial steady-state function of human life. Central nervous system injury can damage the central respiratory pattern generator (CRPG) or interrupt its outflow, leading to central respiratory paralysis and dysfunction, which can endanger the patient's life. At present, there is no effective means to reverse this process. Commonly used non-invasive neuromodulation techniques include repetitive transcranial magnetic stimulation (rTMS), transcranial direct current stimulation (tDCS) and so forth, which have been widely applied in nervous system diseases and their various secondary symptoms, but rarely in respiratory function. Clinical and animal studies have confirmed that TMS is also suitable for investigating the excitability and plasticity of ascending corticospinal respiratory pathways. In addition, although rTMS and tDCS differ in their respective mechanisms, both can regulate respiratory networks in healthy individuals and in diseased states. In this review, we provide an overview of the physiology of respiration, the use of TMS to assess the excitability of corticophrenic pathways in healthy individuals and in central respiratory disorders, followed by an overview of the animal and clinical studies of rTMS, tDCS and so forth in regulating respiratory circuits and the possible mechanisms behind them. It was found that the supplementary motor area (SMA) and the phrenic motor neuron (PMN) may be key regulatory areas. Finally, the challenges and future research directions of neuroregulation in respiratory function are proposed. Through understanding how neuromodulation affects the respiratory neural circuit non-invasively, we can further explore the therapeutic potential of this neuromodulation strategy, so as to promote the recovery of respiratory function after central nervous system diseases or injury.

Prolonged continuous theta burst stimulation increases motor corticospinal excitability and intracortical inhibition in patients with neuropathic pain: An exploratory, single-blinded, randomized controlled trial

OBJECTIVES

A new paradigm for Transcranial Magnetic Stimulation (TMS), referred to as prolonged continuous theta burst stimulation (pcTBS), has recently received attention in the literature because of its advantages over high frequency repetitive TMS (HF-rTMS). Clinical advantages include less time per intervention session and the effects appear to be more robust and reproducible than HF-rTMS to modulate cortical excitability. HF-rTMS targeted at the primary motor cortex (M1) has demonstrated analgesic effects in patients with neuropathic pain but their mechanisms of action are unclear and pcTBS has been studied in healthy subjects only. This study examined the neural mechanisms that have been proposed to play a role in explaining the effects of pcTBS targeted at the M1 and DLPFC brain regions in neuropathic pain (NP) patients with Type 2 diabetes.

METHODS

Forty-two patients with painful diabetic neuropathy were randomized to receive a single session of pcTBS targeted at the left M1 or left DLPFC. pcTBS stimulation consisted of 1,200 pulses delivered in 1 min and 44 s with a 35-45 min gap between sham and active pcTBS stimulation. Both the activity of the descending pain system which was examined using conditioned pain modulation and the activity of the ascending pain system which was assessed using temporal summation of pain were recorded using a handheld pressure algometer by measuring pressure pain thresholds. The amplitude of the motor evoked potential (MEP) was used to measure motor corticospinal excitability and GABA activity was assessed using short (SICI) and long intracortical inhibition (LICI). All these measurements were performed at baseline and post-pcTBS stimulation.

RESULTS

Following a single session of pcTBS targeted at M1 and DLPFC, there was no change in BPI-DN scores and on the activity of the descending (measured using conditioned pain modulation) and ascending pain systems (measured using temporal summation of pain) compared to baseline but there was a significant improvement of >13% in perception of acute pain intensity, increased motor corticospinal excitability (measured using MEP amplitude) and intracortical inhibition (measured using SICI and LICI).

CONCLUSION

In patients with NP, a single session of pcTBS targeted at the M1 and DLPFC modulated the neurophysiological mechanisms related to motor corticospinal excitability and neurochemical mechanisms linked to GABA activity, but it did not modulate the activity of the ascending and descending endogenous modulatory systems. In addition, although BPI-DN scores did not change, there was a 13% improvement in self-reported perception of acute pain intensity.

Evidence for an association of serum microanalytes and myofascial pain syndrome

BACKGROUND

Myofascial Pain Syndrome (MPS) is a common pain disorder. Diagnostic criteria include physical findings which are often unreliable or not universally accepted. A precise biosignature may improve diagnosis and treatment effectiveness. The purpose of this study was to assess whether microanalytic assays significantly correlate with characteristic clinical findings in people with MPS.

METHODS

This descriptive, prospective study included 38 participants (25 women) with greater than 3 months of myofascial pain in the upper trapezius. Assessments were performed at a university laboratory. The main outcome measures were the Beighton Index, shoulder range of motion, strength asymmetries and microanalytes: DHEA, Kynurenine, VEGF, interleukins (IL-1b, IL-2, IL-4, IL-5, IL-7, IL-8, IL-13), growth factors (IGF-1, IGF2, G-CSF, GM-CSF), MCP-1, MIP-1b, BDNF, Dopamine, Noradrenaline, NPY, and Acetylcholine. Mann-Whitney test and Spearman's multivariate correlation were applied for all variables. The Spearman's analysis results were used to generate a standard correlation matrix and heat map matrix.

RESULTS

Mean age of participants was 32 years (20-61). Eight (21%) had widespread pain (Widespread Pain Index ≥ 7). Thirteen (34%) had MPS for 1-3 years, 14 (37%) 3-10 years, and 11 (29%) for > 10 years. The following showed strong correlations: IL1b,2,4,5,7,8; GM-CSF and IL 2,4,5,7; between DHEA and BDNF and between BDNF and Kynurenine, NPY and acetylcholine. The heat map analysis demonstrated strong correlations between the Beighton Index and IL 5,7, GM-CSF, DHEA. Asymmetries of shoulder and cervical spine motion and strength associated with select microanalytes.

CONCLUSION

Cytokine levels significantly correlate with selected clinical assessments. This indirectly suggests possible biological relevance for understanding MPS. Correlations among some cytokine clusters; and DHEA, BDNF kynurenine, NPY, and acetylcholine may act together in MPS. These findings should be further investigated for confirmation that link these microanalytes with select clinical findings in people with MPS.

A randomised sham-controlled study evaluating rTMS analgesic efficacy for postherpetic neuralgia

Context

Postherpetic neuralgia (PHN) is a refractory neuropathic pain condition in which new treatment options are being developed. Repetitive transcranial magnetic stimulation (rTMS) may have the potential to reduce pain sensations in patients with postherpetic neuralgia.

Objectives

This study investigated the efficacy on postherpetic neuralgia by stimulating two potential targets, the motor cortex (M1) and the dorsolateral prefrontal cortex (DLPFC).

Methods

This is a double-blind, randomised, sham-controlled study. Potential participants were recruited from Hangzhou First People's Hospital. Patients were randomly assigned to either the M1, DLPFC or Sham group. Patients received ten daily sessions of 10-Hz rTMS in 2 consecutive weeks. The primary outcome measure was visual analogue scale (VAS) assessed at baseline, first week of treatment (week 1), post-treatment (week 2), 1-week (week 4), 1-month (week 6) and 3-month (week 14) follow-up.

Results

Of sixty patients enrolled, 51 received treatment and completed all outcome assessments. M1 stimulation resulted in a larger analgesia during and after treatment compared to the Sham (week 2 - week 14, p < 0.005), as well as to the DLPFC stimulation (week 1 - week 14, p < 0.05). In addition to pain, sleep disturbance was significantly improved and relieved by targeting either the M1 or the DLPFC (M1: week 4 - week 14, p < 0.01; DLPFC: week 4 - week 14, p < 0.01). Moreover, pain sensations following M1 stimulation uniquely predicted improvement in sleep quality.

Conclusion

M1 rTMS is superior to DLPFC stimulation in treating PHN with excellent pain response and long-term analgesia. Meanwhile, M1 and DLPFC stimulation were equally effective in improving sleep quality in PHN.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2100051963.

Analgesic efficacy of theta-burst stimulation for postoperative pain

OBJECTIVE

Repetitive transcranial magnetic stimulation (rTMS) may be a relevant method to assist postoperative pain. However, studies to date have only used conventional 10 Hz rTMS and targeted the DLPFC for postoperative pain. A more recent form of rTMS, termed intermittent Theta Burst Stimulation (iTBS), enables to increase cortical excitability in a short period of time. This preliminary double-blind, randomised, sham controlled study was designed to evaluate the efficacy of iTBS in postoperative care across two distinct stimulation targets.

METHODS

A group of 45 patients post laparoscopic surgery were randomised to receive a single session of iTBS over either the dorsolateral prefrontal cortex (DLPFC), primary motor cortex (M1), or Sham stimulation (1:1:1 ratio). Outcome measurements were number of pump attempts, total anaesthetic volume used, and self-rated pain experience, assessed at 1 hour, 6 hours, 24 hours, and 48 hours post stimulation. All randomised patients were analysed (n = 15 in each group).

RESULTS

Compared to Sham stimulation, DLPFC-iTBS reduced pump attempts at 6 (DLPFC = 0.73 ± 0.88, Sham = 2.36 ± 1.65, P = 0.031), 24 (DLPFC = 1.40 ± 1.24, Sham = 5.03 ± 3.87, P = 0.008), and 48 (DLPFC = 1.47 ± 1.41, Sham = 5.87 ± 4.34, P = 0.014) hours post-surgery, whereby M1 stimulation had no effect. No group effect was observed on total anaesthetics, which was mainly provided through the continuous administration of opioids at a set speed for each group. There was also no group or interaction effect on pain ratings. Pump attempts were positively associated with pain ratings in the DLPFC (r = 0.59, P = 0.02) and M1 (r = 0.56, P = 0.03) stimulation.

CONCLUSIONS

Our findings show that iTBS to the DLPFC reduces pump attempts for additional anaesthetics following a laparoscopic surgery. However, reduced pump attempts by DLPFC stimulation did not translate into a significantly smaller volume of total anaesthetic, due to the continuous administration of opioids at a set speed for each group.

SIGNIFICANCE

Our findings therefore provide preliminary evidence for iTBS targeting the DLPFC to be used to improve postoperative pain management.

The mechanism and effect of repetitive transcranial magnetic stimulation for post-stroke pain

Post-stroke pain (PSP) is a common complication after stroke and affects patients' quality of life. Currently, drug therapy and non-invasive brain stimulation are common treatments for PSP. Given the poor efficacy of drug therapy and various side effects, non-invasive brain stimulation, such as repetitive transcranial magnetic stimulation (rTMS), has been accepted by many patients and attracted the attention of many researchers because of its non-invasive and painless nature. This article reviews the therapeutic effect of rTMS on PSP and discusses the possible mechanisms. In general, rTMS has a good therapeutic effect on PSP. Possible mechanisms of its analgesia include altering cortical excitability and synaptic plasticity, modulating the release of related neurotransmitters, and affecting the structural and functional connectivity of brain regions involved in pain processing and modulation. At present, studies on the mechanism of rTMS in the treatment of PSP are lacking, so we hope this review can provide a theoretical basis for future mechanism studies.

Effect of Different Physical Therapy Interventions on Brain-Derived Neurotrophic Factor Levels in Chronic Musculoskeletal Pain Patients: A Systematic Review

OBJECTIVE

The main objectives of this review were, firstly, to study the effect of different physiotherapy interventions on BDNF levels, and, secondly, to analyze the influence of physiotherapy on pain levels to subsequently draw conclusions about its possible relationship with BDNF.

BACKGROUND

Based on the theory that neurotrophic factors such as BDNF play a fundamental role in the initiation and/or maintenance of hyperexcitability of central neurons in pain, it was hypothesized that the levels of this neurotrophic factor may be modified by the application of therapeutic interventions, favoring a reduction in pain intensity.

METHODS

A literature search of multiple electronic databases (Pubmed, PsycINFO, Medline (Ebsco), Scopus, WOS, Embase) was conducted to identify randomized control trials (RCTs) published without language restrictions up to and including March 2022. The search strategy was based on the combination of medical terms (Mesh) and keywords relating to the following concepts: "pain", "chronic pain", "brain derived neurotrophic factor", "BDNF", "physiotherapy", and "physical therapy". A total of seven papers were included.

RESULTS

There were two studies that showed statistically significant differences in pain intensity reduction and an increase in the BDNF levels that used therapies such as rTMS and EIMS in patients with chronic myofascial pain. However, the same conclusions cannot be drawn for the other physical therapies applied.

CONCLUSIONS

rTMS and EIMS interventions achieved greater short-term reductions in pain intensity and increased BDNF over other types of interventions in chronic myofascial pain patients, as demonstrated by a moderate amount of evidence. In contrast, other types of physical therapy (PT) interventions did not appear to be more effective in decreasing pain intensity and increasing BDNF levels than placebo PT or minimal intervention, as a low amount of evidence was found.

Opioid tolerance and opioid-induced hyperalgesia: Is TrkB modulation a potential pharmacological solution?

Opioids are widely prescribed for moderate to severe pain in patients with acute illness, cancer pain, and chronic noncancer pain. However, long-term opioid use can cause opioid tolerance and opioid-induced hyperalgesia (OIH), contributing to the opioid misuse and addiction crisis. Strategies to mitigate opioid tolerance and OIH are needed to reduce opioid use and its sequelae. Currently, there are few effective pharmacological strategies that reduce opioid tolerance and OIH. The intrinsic tyrosine kinase receptor B (TrkB) ligand, brain-derived neurotrophic factor (BDNF), has been shown to modulate pain. The BDNF-TrkB signaling plays a role in initiating and sustaining elevated pain sensitivity; however, increasing evidence has shown that BDNF and 7,8-dihydroxyflavone (7,8-DHF), a potent blood-brain barrier-permeable ligand to TrkB, exert neuroprotective, anti-inflammatory, and antioxidant effects that may protect against opioid tolerance and OIH. As such, TrkB signaling may be an important therapeutic avenue in opioid tolerance and OIH. Here, we review 1) the mechanisms of pain, opioid analgesia, opioid tolerance, and OIH; 2) the role of BDNF-TrkB in pain modulation; and 3) the neuroprotective effects of 7,8-DHF and their implications for opioid tolerance and OIH.

Repetitive transcranial magnetic stimulation in patients with fibromyalgia: A protocol for systematic review and network meta-analysis

BACKGROUND

Fibromyalgia is a chronic disease characterized by widespread pain. Repetitive transcranial magnetic stimulation (rTMS) effectively relieves pain intensity in patients with fibromyalgia. The frequency and target site of rTMS have significant roles in therapy effectiveness. However, there is disagreement over the best rTMS protocol. Thus, we will conduct a thorough systematic review and network meta-analysis to rank the efficacy of these various rTMS protocols and determine which is most beneficial in lowering pain and enhancing the quality of life.

METHODS

Databases PubMed, Web of Science, Embase, and Cochrane Library will be searched for clinical randomized controlled trials of rTMS in fibromyalgia. The retrieval time is from the inception of the database until October 1, 2022. Following the Cochrane Handbook, 2 reviewers will independently review the literature, extract data, and evaluate the risk of bias of included articles. Pain intensity and quality of daily life are outcome indicators. Stata 17.0 and ADDIS 1.16.8 software will be used for pairwise meta-analysis and network analysis to evaluate the effectiveness of rTMS and the ranking probability of all protocols. The recommended grading assessment, development, and evaluation will be used to assess the overall quality of the evidence.

RESULTS

The meta-analysis and probability ranking of the network determined the best TMS protocol for fibromyalgia.

CONCLUSION

This study will provide systematic support of evidence-based medicine for TMS in fibromyalgia, integrate the results of direct and indirect comparisons of the efficacy of different rTMS protocol, and provide the best one.

Brain-Derived neurotrophic factor (BDNF) plasma level increases in patients with resistant schizophrenia treated with electroconvulsive therapy (ECT)

OBJECTIVES

The study aimed to assess the effect of Electroconvulsive Therapy (ECT) on plasma BDNF levels in patients with resistant schizophrenia.

METHODS

It was a cohort study that included 60 patients with resistant schizophrenia fulfilling the DSM-5 criteria of schizophrenia and APA criteria of resistant schizophrenia. They were divided into two groups, followed over 4 weeks, and compared to their baseline assessment. Group (A) included 45 patients who received 4-10 sessions of ECT while Group (B) included 15 patients who received the usual treatment with antipsychotics without ECT. The assessment included the severity of psychotic symptoms assessed by the Positive and Negative Symptom Scale (PANSS) in addition to plasma BDNF level.

RESULTS

Patients in Group (A) had an increased level of BDNF after treatment with a statistically significant difference in comparison to their baseline BDNF level (P = 0.027). Meanwhile, patients in group (B) showed a non-significant increase in BDNF. Patients in both groups improved significantly in all PANSS subscales after treatment.

CONCLUSIONS

It was concluded that plasma BDNF levels in patients with resistant schizophrenia increase after electroconvulsive therapy in association with clinical improvement.Key pointsBDNF increases after ECT treatment of resistant schizophrenia.BDNF is not correlated with the severity of psychotic symptomsPatients treated with ECT showed a better response.

Non-invasive Brain Stimulation for Chronic Pain: State of the Art and Future Directions

As a technique that can guide brain plasticity, non-invasive brain stimulation (NIBS) has the potential to improve the treatment of chronic pain (CP) because it can interfere with ongoing brain neural activity to regulate specific neural networks related to pain management. Treatments of CP with various forms of NIBS, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), using new parameters of stimulation have achieved encouraging results. Evidence of moderate quality indicates that high-frequency rTMS of the primary motor cortex has a clear effect on neuropathic pain (NP) and fibromyalgia. However, evidence on its effectiveness regarding pain relief in other CP conditions is conflicting. Concerning tDCS, evidence of low quality supports its benefit for CP treatment. However, evidence suggesting that it exerts a small treatment effect on NP and headaches is also conflicting. In this paper, we describe the underlying principles behind these commonly used stimulation techniques; and summarize the results of randomized controlled trials, systematic reviews, and meta-analyses. Future research should focus on a better evaluation of the short-term and long-term effectiveness of all NIBS techniques and whether they decrease healthcare use, as well as on the refinement of selection criteria.

Prolonged Continuous Theta Burst Stimulation Can Regulate Sensitivity on Aβ Fibers: An Functional Near-Infrared Spectroscopy Study

Objective

High-frequency repetitive transcranial magnetic stimulation (rTMS) induces analgesic effects in both experimental pain and clinical pain conditions. However, whether rTMS can modulate sensory and pain thresholds on sensory fibers is still unclear. Here, we compared the effects of three rTMS paradigms on sensory and pain thresholds conducted by different sensory fibers (Aβ, Aδ, and C fibers) with sham stimulation and investigate the potential brain activation using functional near-infrared spectroscopy (fNIRS).

Methods

Forty right-handed healthy subjects were randomly allocated into one of four groups. Each subject received one session rTMS [prolonged continuous theta-burst stimulation (pcTBS), intermittent theta-burst stimulation (iTBS), 10 Hz rTMS or sham]. Current perception threshold (CPT), pain tolerance threshold (PTT), and fNIRS were measured at baseline, immediately after stimulation, and 1 h after stimulation, respectively.

Results

Significant differences between treatments were observed for changes for CPT 2,000 Hz between baseline and 1 h after rTMS (F = 6.551, P < 0.001): pcTBS versus sham (P = 0.004) and pcTBS versus 10 Hz rTMS (P = 0.007). There were significant difference in average HbO μm in the right frontopolar cortex (FPC) [channel 23: P = 0.030 (pcTBS versus sham: P = 0.036)], left dorsolateral prefrontal cortex (DLPFC) [channel 7: P = 0.006 (pcTBS versus sham: P = 0.004)], left FPC [channel 17: P = 0.014 (pcTBS versus sham: P = 0.046), channel 22: P = 0.004 (pcTBS versus sham: P = 0.004)] comparing four group in 1 h after stimulation in PTT 2000 Hz (Aβ-fiber).

Conclusion

Prolonged continuous theta-burst stimulation can regulate sensitivity on Aβ fibers. In addition, single-session pcTBS placed on left M1 can increase the excitability of DLPFC and FPC, indicating the interaction between M1 and prefrontal cortex may be a potential mechanism of analgesic effect of rTMS. Studies in patients with central post-stroke pain are required to confirm the potential clinical applications of pcTBS.

Stimulation Parameters Used During Repetitive Transcranial Magnetic Stimulation for Motor Recovery and Corticospinal Excitability Modulation in SCI: A Scoping Review

There is a growing interest in non-invasive stimulation interventions as treatment strategies to improve functional outcomes and recovery after spinal cord injury (SCI). Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulatory intervention which has the potential to reinforce the residual spinal and supraspinal pathways and induce plasticity. Recent reviews have highlighted the therapeutic potential and the beneficial effects of rTMS on motor function, spasticity, and corticospinal excitability modulation in SCI individuals. For this scoping review, we focus on the stimulation parameters used in 20 rTMS protocols. We extracted the rTMS parameters from 16 published rTMS studies involving SCI individuals and were able to infer preliminary associations between specific parameters and the effects observed. Future investigations will need to consider timing, intervention duration and dosage (in terms of number of sessions and number of pulses) that may depend on the stage, the level, and the severity of the injury. There is a need for more real vs. sham rTMS studies, reporting similar designs with sufficient information for replication, to achieve a significant level of evidence regarding the use of rTMS in SCI.

Maladaptive motor cortical excitability and connectivity in polyneuropathy with neuropathic pain

BACKGROUND

Sensory symptoms, especially neuropathic pain, are common in polyneuropathy. Conventional diagnostic tools can evaluate structural or functional impairment of nerves but cannot reveal mechanisms of neuropathic pain. Changes in the brain after polyneuropathy may play roles in the genesis of neuropathic pain.

METHODS

This cross-sectional study investigated changes of cortical excitability within left primary motor cortex (M1) by measuring resting motor thresholds, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and afferent inhibition between polyneuropathy patients and controls, and investigated the correlates of these parameters with neuropathic pain and the M1 structural and functional connectivity assessed by diffusion tractography imaging and functional MRI.

RESULTS

Thirty-three painful and 15 non-painful neuropathic patients and 21 controls were enrolled. There were no differences in intraepidermal nerve fiber density, nerve conduction study, thermal thresholds, or autonomic functional tests between patients with and without neuropathic pain. Compared to controls, neuropathic patients exhibited similar resting motor thresholds or afferent inhibition, but attenuated SICI and augmented ICF, especially in painful patients. Changes of intracortical excitability in neuropathic patients were correlated with intensities of neuropathic pain, and different presentations of SICI and ICF were noted between patients with and without thermal paresthesia. Additionally, short latency afferent inhibition at interstimulus intervals of 20 ms was associated with structural connectivity of left M1 with brain areas associated with pain perception.

CONCLUSIONS

Maladaptive cortical excitability with altered structural connectivity in left M1 developed after peripheral nerve degeneration and was associated with neuropathic pain and sensory symptoms in polyneuropathy.

Analgesic Effects of Navigated Repetitive Transcranial Magnetic Stimulation in Patients With Acute Central Poststroke Pain

INTRODUCTION

Central poststroke pain (CPSP) develops commonly after stroke, which impairs the quality of life, mood, and social functioning. Current pharmacological approaches for the treatment of CPSP are not satisfactory. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique which has been recommended for the treatment of chronic CPSP. However, few studies have evaluated the analgesic effects of rTMS in patients with acute neuropathic pain after stroke.

METHODS

We evaluated the analgesic effects of rTMS applied over the upper extremity area of the motor cortex (M1) in patients with acute CPSP. Forty patients were randomized to receive either rTMS (10 Hz, 2000 stimuli) (n = 20) or a sham intervention (n = 20) for 3 weeks. The Numeric Rating Scale (NRS), Short-form McGill Pain Questionnaire-2 (SF-MPQ-2, Chinese version), Hamilton Anxiety Scale (HAM-A), Hamilton Depression Scale (HAM-D), brain-derived neurotrophic factor (BDNF) levels, and motor-evoked potentials (MEP) were analyzed at baseline, 3 days, 1 week, 2 weeks, and 3 weeks.

RESULTS

Significant treatment-time interactions were found for pain intensity. Compared with the sham group, the NRS and SF-MPQ-2 scores were significantly lower on the seventh day of treatment in the rTMS group (P < 0.001, Cohen's d = 1.302) (P = 0.003, Cohen's d = 0.771), and this effect lasted until the third week (P = 0.001, Cohen's d = 0.860) (P = 0.027, Cohen's d = 0.550). The HAM-A and HAM-D scores did not change in the rTMS group when compared with the sham group (P = 0.341, Cohen's d = 0.224) (P = 0.356, Cohen's d = 0.217). The serum BDNF levels were significantly higher in the treated group (P = 0.048, Cohen's d = -0.487), and the resting motor threshold (RMT) decreased by 163.65%.

CONCLUSION

Our findings indicate that rTMS applied over the upper extremity area of the motor cortex can effectively alleviate acute CPSP, possibly by influencing cortical excitability and serum BDNF secretion.

TRIAL REGISTRATION

This trial is registered with Clinical Trial Registry of China: Reg. No. ChiCTR-INR-17012880.

Repetitive transcranial magnetic stimulation for fibromyalgia patients: A Systematic Review with Meta-Analysis

OBJECTIVE

Fibromyalgia is a poorly understood pain syndrome. Repetitive transcranial magnetic stimulation is a noninvasive brain stimulation therapy and is commonly applied for the management of fibromyalgia. However, controversy regarding its efficacy remains. Therefore, a meta-analysis was conducted to evaluate the effectiveness of repetitive transcranial magnetic stimulation (rTMS) for fibromyalgia syndrome.

METHOD

Four medical databases and one physiotherapy database were screened for randomized controlled trials. A systematic review and meta-analysis was performed. Numerical Pain Rating Scale (NPRS), Beck Depression Inventory (BDI), Hospital Anxiety and Depression Scale (HADS) anxiety score, Pain Catastrophizing Scale (PCS), Fatigue Severity Scale (FSS), Short Form-36 general health survey mental score, and Fibromyalgia Impact Questionnaire (FIQ) were set as outcome measures.

RESULTS

Analysis of 14 studies and 433 participants indicated that rTMS exerted more favorable effects on the NPRS than sham rTMS after treatment (standardized mean difference = -0.49, 95% confidence interval = -0.86 to - 0.13, P = 0.008, I2 = 68%) and FIQ (standardized mean difference = -0.50, 95% confidence interval = -0.75 to - 0.25, P = 0.0001, I2 = 28%). However, the BDI, FSS, PCS, mood index, and HADS scores showed no significant difference compared with sham rTMS after treatment. The mean methodological quality of included studies was an acceptable score of 8.5 based on the PEDro scale, suggesting the validity of our conclusions.

CONCLUSION

This study demonstrated that rTMS relieved pain and enhanced quality of life of patients with fibromyalgia; however, it did not improve anxiety, depression, and other symptoms based on current reports.

High frequency repetitive Transcranial Magnetic Stimulation promotes long lasting phrenic motoneuron excitability via GABAergic networks

Repetitive transcranial magnetic stimulation (rTMS) is a promising, innovative, and non-invasive therapy used clinically. Efficacy of rTMS has been demonstrated to ameliorate psychiatric disorders and neuropathic pain through neuromodulation of affected neural circuits. However, little is known about the mechanisms and the specific neural circuits via which rTMS facilitates these functional effects. The aim of this study was to begin revealing the mechanisms by which rTMS may tap into existing neural circuits, by using a well characterized spinal motor circuit - the phrenic circuit. Here we hypothesized that rTMS can be used to enhance phrenic motoneuron excitability in anesthetized Sprague Dawley rats. Multiple acute rTMS protocols were used revealing 10 Hz rTMS protocol induced a robust, long-lasting increase in phrenic motoneuron excitability, functionally evaluated by diaphragm motor evoked potentials (59.1 ± 21.1 % of increase compared to baseline 60 min after 10 Hz protocol against 6.0 ± 5.8 % (p = 0.007) for Time Control, -5.8 ± 7.4 % (p < 0.001) for 3 Hz, and 5.2 ± 12.5 % (p = 0.008) for 30 Hz protocols). A deeper analyze allowed to discriminate "responder" and "non-responder" subgroups among 10 Hz rTMS treated animals. Intravenous injections of GABA_A and GABA_B receptor agonists prior to 10 Hz rTMS treatment, abolished the enhanced phrenic motoneuron excitability, suggesting GABAergic input plays a mechanistic role in rTMS-induced phrenic excitability. These data demonstrate that a single high frequency rTMS protocol at 10 Hz increases phrenic motoneuron excitability, mediated by a local GABAergic "disinhibition". By understanding how rTMS can be used to affect neural circuits non-invasively we can begin to harness the therapeutic potential of this neuromodulatory strategy to promote recovery after disease or injury to the central nervous system.

Brain-Derived Neurotrophic Factor Modulates the Effect of Sex on the Descending Pain Modulatory System in Healthy Volunteers

OBJECTIVES

We investigated sex differences and the influence of brain-derived neurotrophic factor (BDNF) in the descending pain modulatory system (DPMS), as measured by change on the numerical pain scale (NPS; 0-10) during conditioned pain modulation (CPM task; primary outcome) and by function of the corticospinal motor pathway and heat pain thresholds (HPTs; secondary outcomes).

METHODS

This cross-sectional study included healthy volunteers ranging in age from 18 to 45 years (32 male and 24 female). Assessment included serum BDNF, HPT, change on the NPS (0-10) during the CPM task, and motor-evoked potential (MEP) using transcranial magnetic stimulation (TMS).

RESULTS

The MEP (Mv) amplitude was larger in male participants compared with female participants (mean [SE] = 1.55 [0.34] vs mean [SE] = 1.27 [0.27], respectively, P = 0.001). The mean NPS (0-10) during CPM task changed more substantially for female compared with male participants (mean [SE] = -3.25 [2.01] vs mean [SE] = -2.29 [1.34], respectively, P = 0.040). In addition, a higher serum BDNF (adjusted index for age) was associated with a larger decrease of the NPS during CPM task (P = 0.003), although further regression analyses by sex showed that this was only significant for females (P = 0.010).

CONCLUSIONS

Significant sex differences were identified in DPMS function and corticospinal motor pathway integrity. Nevertheless, BDNF was associated with the function of the DPMS in female but not male participants, indicating that sex and neuroplasticity state are crucial factors for pain perception in healthy subjects.

Noninvasive motor cortex stimulation effects on quantitative sensory testing in healthy and chronic pain subjects: a systematic review and meta-analysis

ABSTRACT

One of the potential mechanisms of motor cortex stimulation by noninvasive brain stimulation (NIBS) effects on pain is through the restoration of the defective endogenous inhibitory pain pathways. However, there are still limited data on quantitative sensory testing (QST), including conditioned pain modulation (CPM), supporting this mechanism. This systematic review and meta-analysis aimed to evaluate the effects of noninvasive motor cortex stimulation on pain perception as indexed by changes in QST outcomes. Database searches were conducted until July 2019 to include randomized controlled trials that performed sham-controlled NIBS on the motor cortex in either the healthy and/or pain population and assessed the QST and CPM. Quality of studies was assessed through the Cochrane tool. We calculated the Hedge's effect sizes of QST and CPM outcomes and their 95% confidence intervals (95% CIs) and performed random-effects meta-analyses. Thirty-eight studies were included (1178 participants). We found significant increases of pain threshold in healthy subjects (ES = 0.16, 95% CI = 0.02-0.31, I2 = 22.2%) and pain populations (ES = 0.48, 95% CI = 0.15-0.80, I2 = 68.8%), and homogeneous higher CPM effect (pain ratings reduction) in healthy subjects (ES = -0.39, 95% CI = -0.64 to -0.14, I2 = 17%) and pain populations (ES = -0.35, 95% CI = -0.60 to -0.11, I2 = 0%) in the active NIBS group compared with sham. These results support the idea of top-down modulation of endogenous pain pathways by motor cortex stimulation as one of the main mechanisms of pain reduction assessed by QST, which could be a useful predictive and prognostic biomarker for chronic pain personalized treatment with NIBS.

Correlation Between Central Sensitization and Remote Muscle Performance in Individuals With Chronic Low Back Pain

OBJECTIVE

The purpose of this study was to examine associations between the degree of central sensitization (CS) and remote muscle performance in people with chronic low back pain (CLBP).

METHODS

The 2011 fibromyalgia (FM) criteria and severity scales (2011 FM survey) were used as a surrogate measure of CS to divide the participants into 2 groups: FM-positive CLBP and FM-negative CLBP. Measures related to central sensitization included the 2011 FM survey and pressure pain threshold of the thumbnail. Measures related to muscle performance included neck flexor muscle strength and endurance and plantar flexor muscle strength. Between-groups and correlation analyses were performed.

RESULTS

Sixty people with CLBP were enrolled (30 FM-positive, 30 FM-negative). There was no significant difference between the subgroups in age, sex, or pain duration (P > .05). The FM-positive CLBP group showed poorer neck flexor muscle endurance (P = .01) and plantar flexor muscle strength (P = .002) than the FM-negative CLBP group, whereas neck flexor muscle strength was not different between the groups (P = .175). Scores for FM and values for pressure pain thresholds of the thumbnail were associated with neck flexor muscle strength (respectively, r = -0.320, P = .013, and r = 0.467, P < .001), endurance (r = -0.242, P < .001, and r = 0.335, P = .009), and plantar flexor muscle strength (r = -0.469, P < .001, and r = 0.500, P < .001).

CONCLUSION

We found associations between the degree of CS and remote muscle strength and endurance, suggesting that poor remote muscle performance is possibly a clinical sign of CS in people with CLBP.

Efficacy of Physical Therapy on Nociceptive Pain Processing Alterations in Patients with Chronic Musculoskeletal Pain: A Systematic Review and Meta-analysis

INTRODUCTION

Chronic musculoskeletal pain is a major health, social, and economic problem. Most of the subjects who suffer from chronic musculoskeletal pain present processes of central sensitization. Temporal summation and conditioned pain modulation are the two most commonly used clinical measures of this. The objective of this review is to evaluate the effects of physical therapy on temporal summation (TS) and conditioned pain modulation (CPM) in patients with chronic musculoskeletal pain.

METHODS

This is a systematic review and meta-analysis. We searched the MEDLINE, EMBASE, CINAHL, EBSCO, PubMed, PEDro, Cochrane Collaboration Trials Register, Cochrane Database of Systematic Reviews, and SCOPUS databases. Different mesh terms and key words were combined for the search strategy, with the aim of encompassing all studies that have used any type of physical therapy treatment in patients with chronic musculoskeletal pain and have measured both TS and CPM.

RESULTS

Eighteen studies remained for qualitative analysis and 16 for quantitative analysis. Statistically significant differences with a 95% confidence interval (CI) were obtained for TS (-0.21, 95% CI = -0.39 to -0.03, Z = 2.50, P = 0.02, N = 721) and CPM (0.34, 95% CI = 0.12 to 0.56, Z = 2.99, P = 0.003, N = 680) in favor of physical therapy as compared with control. Manual therapy produces a slight improvement in TS, and physical therapy modalities in general improve CPM. No significant differences between the subgroups of the meta-analysis were found. The methodological quality of the studies was high.

CONCLUSIONS

Physical therapy produces a slight improvement in central sensitization (CS)-related variables, with TS decreased and CPM increased when compared with a control group in patients with CMP. Only significant differences in TS were identified in the manual therapy subgroup.

A capital role for the brain's insula in the diverse fibromyalgia-associated symptoms

Unexplained yet persisting general and widespread non-articular musculoskeletal pain and the associated complaints, known as fibromyalgia (FM), is a common disorder with major social and economic impact. We postulate that in FM disturbance of neurotransmitter balances at the brain's insula not only leads to aberrant pain processing but could also govern other associated symptoms. Symptoms might arise from central nervous system dysregulation mediated through an imbalance between the excitatory neurotransmitter glutamate and the inhibitory transmitter gamma-amino butyric acid. The insula could also have a leading role in the dysregulation of heart rate and blood pressure, bladder and bowel symptoms, and anxiety and sleep disturbances which are experienced by many FM patients. The presented hypothesis explains how the diverse FM-associated symptoms could be linked, and puts the brain's insula forward as a possible therapeutic target to be further explored for FM.

Repetitive transcranial magnetic stimulation of the prefrontal cortex for fibromyalgia syndrome: a randomised controlled trial with 6-months follow up

Objectives

Fibromyalgia Syndrome (FMS), is a chronic pain disorder with poorly understood pathophysiology. In recent years, repetitive transcranial magnetic stimulation (rTMS) has been recommended for pain relief in various chronic pain disorders. The objective of the present research was to study the effect of low frequency rTMS over the right dorsolateral prefrontal cortex (DLPFC) on pain status in FMS.

Methods

Ninety diagnosed cases of FMS were randomized into Sham-rTMS and Real-rTMS groups. Real rTMS (1 Hz/1200 pulses/8 trains/90% resting motor threshold) was delivered over the right DLPFC for 5 consecutive days/week for 4 weeks. Pain was assessed by subjective and objective methods along with oxidative stress markers. Patients were followed up for 6 months (post-rTMS;15 days, 3 months and 6 months).

Results

In Real-rTMS group, average pain ratings and associated symptoms showed significant improvement post rTMS. The beneficial effects of rTMS lasted up to 6 months in the follow-up phase. In Sham-rTMS group, no significant change in pain ratings was observed.

Conclusion

Right DLPFC rTMS can significantly reduce pain and associated symptoms of FMS probably through targeting spinal pain circuits and top-down pain modulation .

Trial registration: Ref No: CTRI/2013/12/004228.

Effect of Repetitive Transcranial Magnetic Stimulation on Pain Management: A Systematic Narrative Review

Recently, clinicians have been using repetitive transcranial magnetic stimulation (rTMS) for treating various pain conditions. This systematic narrative review aimed to examine the use and efficacy of rTMS for controlling various pain conditions. A PubMed search was conducted for articles that were published until June 7, 2019 and used rTMS for pain alleviation. The key search phrase for identifying potentially relevant articles was (repetitive transcranial magnetic stimulation AND pain). The following inclusion criteria were applied for article selection: (1) patients with pain, (2) rTMS was applied for pain management, and (3) follow-up evaluations were performed after rTMS stimulation to assess the reduction in pain. Review articles were excluded. Overall, 1,030 potentially relevant articles were identified. After reading the titles and abstracts and assessing eligibility based on the full-text articles, 106 publications were finally included in our analysis. Overall, our findings suggested that rTMS is beneficial for treating neuropathic pain of various origins, such as central pain, pain from peripheral nerve disorders, fibromyalgia, and migraine. Although data on the use of rTMS for orofacial pain, including trigeminal neuralgia, phantom pain, low back pain, myofascial pain syndrome, pelvic pain, and complex regional pain syndrome, were promising, there was insufficient evidence to determine the efficacy of rTMS for treating these conditions. Therefore, further studies are needed to validate the effects of rTMS on pain relief in these conditions. Overall, this review will help guide clinicians in making informed decisions regarding whether rTMS is an appropriate option for managing various pain conditions.

Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS): An update (2014-2018)

A group of European experts reappraised the guidelines on the therapeutic efficacy of repetitive transcranial magnetic stimulation (rTMS) previously published in 2014 [Lefaucheur et al., Clin Neurophysiol 2014;125:2150-206]. These updated recommendations take into account all rTMS publications, including data prior to 2014, as well as currently reviewed literature until the end of 2018. Level A evidence (definite efficacy) was reached for: high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the painful side for neuropathic pain; HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC) using a figure-of-8 or a H1-coil for depression; low-frequency (LF) rTMS of contralesional M1 for hand motor recovery in the post-acute stage of stroke. Level B evidence (probable efficacy) was reached for: HF-rTMS of the left M1 or DLPFC for improving quality of life or pain, respectively, in fibromyalgia; HF-rTMS of bilateral M1 regions or the left DLPFC for improving motor impairment or depression, respectively, in Parkinson's disease; HF-rTMS of ipsilesional M1 for promoting motor recovery at the post-acute stage of stroke; intermittent theta burst stimulation targeted to the leg motor cortex for lower limb spasticity in multiple sclerosis; HF-rTMS of the right DLPFC in posttraumatic stress disorder; LF-rTMS of the right inferior frontal gyrus in chronic post-stroke non-fluent aphasia; LF-rTMS of the right DLPFC in depression; and bihemispheric stimulation of the DLPFC combining right-sided LF-rTMS (or continuous theta burst stimulation) and left-sided HF-rTMS (or intermittent theta burst stimulation) in depression. Level A/B evidence is not reached concerning efficacy of rTMS in any other condition. The current recommendations are based on the differences reached in therapeutic efficacy of real vs. sham rTMS protocols, replicated in a sufficient number of independent studies. This does not mean that the benefit produced by rTMS inevitably reaches a level of clinical relevance.

Transcranial Direct Current Stimulation to Improve the Dysfunction of Descending Pain Modulatory System Related to Opioids in Chronic Non-cancer Pain: An Integrative Review of Neurobiology and Meta-Analysis

Background: Opioid long-term therapy can produce tolerance, opioid-induced hyperalgesia (OIH), and it induces dysfunction in pain descending pain inhibitory system (DPIS). Objectives: This integrative review with meta-analysis aimed: (i) To discuss the potential mechanisms involved in analgesic tolerance and opioid-induced hyperalgesia (OIH). (ii) To examine how the opioid can affect the function of DPIS. (ii) To show evidence about the tDCS as an approach to treat acute and chronic pain. (iii) To discuss the effect of tDCS on DPIS and how it can counter-regulate the OIH. (iv) To draw perspectives for the future about the tDCS effects as an approach to improve the dysfunction in the DPIS in chronic non-cancer pain. Methods: Relevant published randomized clinical trials (RCT) comparing active (irrespective of the stimulation protocol) to sham tDCS for treating chronic non-cancer pain were identified, and risk of bias was assessed. We searched trials in PubMed, EMBASE and Cochrane trials databases. tDCS protocols accepted were application in areas of the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), or occipital area. Results: Fifty-nine studies were fully reviewed, and 24 with moderate to the high-quality methodology were included. tDCS improved chronic pain with a moderate effect size [pooled standardized mean difference; -0.66; 95% confidence interval (CI) -0.91 to -0.41]. On average, active protocols led to 27.26% less pain at the end of treatment compared to sham [95% CI; 15.89-32.90%]. Protocol varied in terms of anodal or cathodal stimulation, areas of stimulation (M1 and DLPFC the most common), number of sessions (from 5 to 20) and current intensity (from 1 to 2 mA). The time of application was 20 min in 92% of protocols. Conclusion: In comparison with sham stimulation, tDCS demonstrated a superior effect in reducing chronic pain conditions. They give perspectives that the top-down neuromodulator effects of tDCS are a promising approach to improve management in refractory chronic not-cancer related pain and to enhance dysfunctional neuronal circuitries involved in the DPIS and other pain dimensions and improve pain control with a therapeutic opioid-free. However, further studies are needed to determine individualized protocols according to a biopsychosocial perspective.

Analgesic Effects of Directed Repetitive Transcranial Magnetic Stimulation in Acute Neuropathic Pain After Spinal Cord Injury

Objectives

Central neuropathic pain (CNP) often appears following spinal cord injury (SCI), but current treatments are not always successful. In this study, we evaluated the analgesic effects of repetitive transcranial magnetic stimulation (rTMS) applied over the hand area of the motor cortex in patients with acute CNP after SCI.

Methods

A total of 48 patients with complete or incomplete SCI and acute CNP participated in this study and were randomized to receive either rTMS (10 Hz, 1,500 stimuli; N = 24) or a sham intervention (N = 24) for three weeks. The numeric rating scale (NRS) and Short-Form McGill Pain Questionnaire-2 (Chinese Edition; SF-MPQ-2-CN) were analyzed to assess the degree of pain. Brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were collected to explore expression influenced by rTMS. Motor-evoked potential (MEP) latency and maximal amplitude were measured to determine neurophysiological changes. The assessments were carried out at baseline (T0), three days (T1), one week (T2), two weeks (T3), and three weeks (T4) after onset of treatment.

Results

The analysis showed significant treatment–time interactions for the quality and intensity of pain, as measured by NRS (P &lt; 0.001, η2 = 0.441) and SF-MPQ-2 (P &lt; 0.001, η2 = 0.590). Compared with the sham group, the NRS and SF-MPQ2-CN scores were significantly lower on the third day (P &lt; 0.001, Cohen’s d = 1.135; P = 0.006, Cohen’s d = 0.616) and after one week (P &lt; 0.001, Cohen’s d = 0.846; P = 0.012, Cohen’s d = 0.557) of treatment. In addition, the serum levels of BDNF and NGF were significantly higher in the treated group after three weeks (P = 0.015, Cohen’s d = 0.539; P = 0.009, Cohen’s d = 0.580), and the MEP amplitude increased by 109.59% (P = 0.033, Cohen’s d = 0.464).

Conclusions

These findings indicate that 10 Hz rTMS over the hand area of the motor cortex could alleviate acute CNP in the early phase of SCI and could enhance MEP parameters and modulate BDNF and NGF secretion.

Higher Cortical Facilitation and Serum BDNF Are Associated with Increased Sensitivity to Heat Pain and Reduced Endogenous Pain Inhibition in Healthy Males

Background

Although the brain-derived neurotrophic factor (BDNF) has been intensively investigated in animal models of chronic pain, its role in human pain processing is less understood.

Objective

To study the neurophysiology of BDNF modulation on acute experimental pain, we performed a cross-sectional study.

Methods

We recruited 20 healthy male volunteers (19-40 years old) and assessed their serum BDNF levels, quantitative sensory testing, and cortical excitability parameters using transcranial magnetic stimulation.

Results

Linear regression models demonstrated that the BDNF (β = -5.245, P = 0.034) and intracortical facilitation (β = -3.311, P = 0.034) were inversely correlated with heat pain threshold (adjusted R2 = 44.26). The BDNF (β = -3.719, P ≤ 0.001) was also inversely correlated with conditioned pain modulation (adjusted R2 = 56.8).

Conclusions

Our findings indicate that higher serum BDNF and intracortical facilitation of the primary motor cortex are associated with increased sensitivity to heat pain and high serum BDNF with reduced pain inhibition during noxious heterotopic stimulation.

Differential Neuroplastic Changes in Fibromyalgia and Depression Indexed by Up-Regulation of Motor Cortex Inhibition and Disinhibition of the Descending Pain System: An Exploratory Study

Background: Major depressive disorder (MDD) and fibromyalgia (FM) present overlapped symptoms. Although the connection between these two disorders has not been elucidated yet, the disruption of neuroplastic processes that mediate the equilibrium in the inhibitory systems stands out as a possible mechanism. Thus, the purpose of this cross-sectional exploratory study was: (i) to compare the motor cortex inhibition indexed by transcranial magnetic stimulation (TMS) measures [short intracortical inhibition (SICI) and intracortical facilitation (ICF)], as well as the function of descending pain modulatory systems (DPMS) among FM, MDD, and healthy subjects (HS); (ii) to compare SICI, ICF, and the role of DPMS evaluated by the change on Numerical Pain Scale (NPS) during the conditioned pain modulation test (CPM-test) between FM and MDD considering the BDNF-adjusted index; (iii) to assess the relationship between the role of DPMS and the BDNF-adjusted index, despite clinical diagnosis. Patients and Methods: A cohort of 63 women, aged 18 to 75 years [FM (n = 18), MDD (n = 19), and HC (n = 29)]. Results: The MANCOVA analysis revealed that the mean of SICI was 53.40% larger in FM compared to MDD [1.03 (0.50) vs. 0.55 (0.43)] and 66.99% larger compared to HC [1.03 (0.50) vs. 0.34 (0.19)], respectively. The inhibitory potency of the DPMS assessed by the change on the NPS during CPM-test was 112.29 % lower in the FM compared to MDD [0.22 (1.37) vs. -0.87 (1.49)]. The mean of BDNF from FM compared to MDD was 35.70% higher [49.82 (16.31) vs. 14.12 (8.86)]. In FM, the Spearman's coefficient between the change in the NPS during CPM-test with the SICI was Rho = -0.49, [confidence interval (CI) 95%; -0.78 to -0.03]. The BDNF-adjusted index was positively correlated with the disinhibition of the DPMS. Conclusion: These findings support the hypothesis that in FM a deteriorated function of cortical inhibition, indexed by a higher SICI parameter, a lower function of the DPMS, together with a higher level of BDNF indicate that FM has different pathological substrates from depression. They suggest that an up-regulation phenomenon of intracortical inhibitory networks associated with a disruption of the DPMS function occurs in FM.

The Value of High-Frequency Repetitive Transcranial Magnetic Stimulation of the Motor Cortex to Treat Central Pain Sensitization Associated With Knee Osteoarthritis

Aim

Chronic pain associated with knee osteoarthritis may develop in connection with a maladaptive process of pain sensitization in the central nervous system. Repetitive transcranial magnetic stimulation (rTMS) has been proposed to treat various pain syndromes related to central sensitization phenomenon, but was never applied in the context of knee osteoarthritis.

Methods

A 71-year-old woman presenting clinical evidence of central sensitization of pain associated with left knee osteoarthritis underwent monthly sessions of rTMS delivered at 10 Hz over the right motor cortex.

Results

From the week following the third session, she began to improve on various clinical aspects, including pain. After 10 sessions (i.e., almost one year of follow-up), pain was reduced by 67%, especially regarding neuropathic components, while sleep disorders and fatigue also improved by 57–67%. The central sensitization inventory (CSI) score was reduced by 70%.

Conclusion

This observation suggests that high-frequency motor cortex rTMS could be a therapeutic option to treat neuropathic pain and psychological symptoms associated with central sensitization developing in the context of chronic osteoarthritis of the knee joint.

Motor corticospinal excitability: a novel facet of pain modulation?

Introduction

Increase in excitability of the primary motor cortex (M1) is associated with pain inhibition by analgesics, which is, in turn, associated with the psychophysical antinociceptive pain modulation profile. However, the relationship between neurophysiological M1 excitability and psychophysical pain modulation has not yet been explored.

Objectives

We aim to study these relationships in healthy subjects.

Methods

Forty-one young healthy subjects (22 women) underwent a wide battery of psychophysical testing that included conditioned pain modulation (CPM) and pain temporal summation, and a transcranial magnetic stimulation neurophysiological assessment of the motor corticospinal excitability, including resting motor threshold, motor-evoked potentials (MEPs), and cortical silent period.

Results

Increased motor corticospinal excitability in 2 parameters was associated with more efficient CPM: (1) higher MEP amplitude (r = -0.574; P _{_Bonferroni} = 0.02) and (2) longer MEP duration (r = -0.543; P _{_Bonferroni} = 0.02). The latter also correlated with the lower temporal summation magnitude (r = -0.421; P = 0.007); however, on multiplicity adjustment, significance was lost.

Conclusions

Increased corticospinal excitability of the primary motor cortex is associated with more efficient inhibitory pain modulation as assessed by CPM, in healthy subjects. Motor-evoked potential amplitude and duration may be considered as an additional, objective and easy to measure parameter to allow for better individual assessment of pain modulation profile.

Latin American and Caribbean consensus on noninvasive central nervous system neuromodulation for chronic pain management (LAC2-NIN-CP)

Supplemental Digital Content is Available in the Text.

Introduction:

Chronic pain (CP) is highly prevalent and generally undertreated health condition. Noninvasive brain stimulation may contribute to decrease pain intensity and influence other aspects related to CP.

Objective:

To provide consensus-based recommendations for the use of noninvasive brain stimulation in clinical practice.

Methods:

Systematic review of the literature searching for randomized clinical trials followed by consensus panel. Recommendations also involved a cost-estimation study.

Results:

The systematic review wielded 24 transcranial direct current stimulation (tDCS) and 22 repetitive transcranial magnetic stimulation (rTMS) studies. The following recommendations were provided: (1) Level A for anodal tDCS over the primary motor cortex (M1) in fibromyalgia, and level B for peripheral neuropathic pain, abdominal pain, and migraine; bifrontal (F3/F4) tDCS and M1 high-definition (HD)-tDCS for fibromyalgia; Oz/Cz tDCS for migraine and for secondary benefits such as improvement in quality of life, decrease in anxiety, and increase in pressure pain threshold; (2) level A recommendation for high-frequency (HF) rTMS over M1 for fibromyalgia and neuropathic pain, and level B for myofascial or musculoskeletal pain, complex regional pain syndrome, and migraine; (3) level A recommendation against the use of anodal M1 tDCS for low back pain; and (4) level B recommendation against the use of HF rTMS over the left dorsolateral prefrontal cortex in the control of pain.

Conclusion:

Transcranial DCS and rTMS are recommended techniques to be used in the control of CP conditions, with low to moderate analgesic effects, and no severe adverse events. These recommendations are based on a systematic review of the literature and a consensus made by experts in the field. Readers should use it as part of the resources available to decision-making.

Insights About the Neuroplasticity State on the Effect of Intramuscular Electrical Stimulation in Pain and Disability Associated With Chronic Myofascial Pain Syndrome (MPS): A Double-Blind, Randomized, Sham-Controlled Trial

Background: There is limited evidence concerning the effect of intramuscular electrical stimulation (EIMS) on the neural mechanisms of pain and disability associated with chronic Myofascial Pain Syndrome (MPS). Objectives: To provide new insights into the EIMS long-term effect on pain and disability related to chronic MPS (primary outcomes). To assess if the neuroplasticity state at baseline could predict the long-term impact of EIMS on disability due to MPS we examined the relationship between the serum brain-derived-neurotrophic-factor (BDNF) and by motor evoked potential (MEP). Also, we evaluated if the EIMS could improve the descending pain modulatory system (DPMS) and the cortical excitability measured by transcranial magnetic stimulation (TMS) parameters. Methods: We included 24 right-handed female with chronic MPS, 19-65 years old. They were randomically allocated to receive ten sessions of EIMS, 2 Hz at the cervical paraspinal region or a sham intervention (n = 12). Results: A mixed model analysis of variance revealed that EIMS decreased daily pain scores by -73.02% [95% confidence interval (CI) = -95.28 to -52.30] and disability due to pain -43.19 (95%CI, -57.23 to -29.39) at 3 months of follow up. The relative risk for using analgesics was 2.95 (95% CI, 1.36 to 6.30) in the sham group. In the EIMS and sham, the change on the Numerical Pain Scale (NPS0-10) throughout CPM-task was -2.04 (0.79) vs. -0.94 (1.18), respectively, (P = 0.01). EIMS reduced the MEP -28.79 (-53.44 to -4.15), while improved DPMS and intracortical inhibition. The MEP amplitude before treatment [(Beta = -0.61, (-0.58 to -0.26)] and a more significant change from pre- to post-treatment on serum BDNF) (Beta = 0.67; CI95% = 0.07 to 1.26) were predictors to EIMS effect on pain and disability due to pain. Conclusion: These findings suggest that a bottom-up effect induced by the EIMS reduced the analgesic use, improved pain, and disability due to chronic MPS. This effect might be mediated by an enhancing of corticospinal inhibition as seen by an increase in IC and a decrease in MEP amplitude. Likewise, the MEP amplitude before treatment and the changes induced by the EIMS in the serum BDNF predicted it's long-term clinical impact on pain and disability due MPS. The trial is recorded in ClinicalTrials.gov: NCT02381171.

The effect of bilateral low-frequency rTMS over dorsolateral prefrontal cortex on serum brain-derived neurotropic factor and serotonin in patients with generalized anxiety disorder

To investigate the effect of bilateral low-frequency repetitive transcranial magnetic stimulation (rTMS) over dorsolateral prefrontal cortex on serum brain-derived neurotropic factor (BDNF) and serotonin (5-HT) in patients with generalized anxiety disorders (GAD). As compared with before treatment, the HARS score in patients markedly decreased after treatment, and the levels of serum BDNF and 5-HT were significantly higher. Pearson correlation analysis revealed that the increase in the level of serum 5-HT was positively associated with the increase of the level of serum BDNF, and the change of anxiety score was negatively associated with the change of the level of serum BDNF and 5-HT. The results suggested that alleviation of GAD by bilateral low-frequency rTMS may be involved in the increase of the level of BDNF and the release of 5-HT in the brain.