Time perception and pain: Can a temporal illusion reduce the intensity of pain?

It is commonly known-and previous studies have indicated-that time appears to last longer during unpleasant situations. This study examined whether a reciprocal statement can be made-that is, whether changes in the perception of time can influence our judgment (or rating) of a negative event. We used a temporal illusion method (Pomares et al. Pain 152, 230-234, 2011) to induce distortions in the perception of time. Two stimuli were presented for a constant time: a full clock, which stayed on the screen until its clock hand completed a full rotation (360°); and a short clock, in which the clock hand moved just three-quarters of the way (270°), thus suggesting a reduced interval duration. However, both stimuli were shown for the same amount of time. We specifically investigated (a) whether we could induce a temporal illusion with this simple visual manipulation, and (b) whether this illusion could change participants' ratings of a painful stimulus. In Experiment I (n = 22), to answer (a) above, participants were asked to reproduce the duration in which the different clocks were presented. In Experiment II (n = 30), a painful thermal stimulation was applied on participants' hands while the clocks were shown. Participants were asked to rate the perceived intensity of their pain, and to reproduce its duration. Results showed that, for both experiments, participants reproduced a longer interval after watching the full clock compared with the short clock, confirming that the clock manipulation was able to induce a temporal illusion. Furthermore, the second experiment showed that participants rated the thermal stimuli as less painful when delivered with the short clock than with the full clock. These findings suggest that temporal distortions can modulate the experience of pain.

Pain, psychoaffective symptoms, and quality of life in human T cell lymphotropic virus type 1 (HTLV-1): a cross-sectional study.

The objective of this study is to describe the chronic pain characteristics in individuals infected with human T cell lymphotropic virus type 1 (HTLV-1) per subgroup (asymptomatic, oligosymptomatic, and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP)) compared with controls with chronic pain without HTLV-1. This is a cross-sectional study investigating associations between pain profile, psychopathological symptoms, and quality of life. Individuals infected with HTLV-1 refer high-intensity pain compared with controls, with more severe characteristics being present in oligosymptomatic and HAM/TSP individuals. Oligosymptomatic individuals have a tendency of diffuse and frequent pain, mainly in the head/neck region and more depressive symptoms, resembling nociplastic pain. Neuropathic pain was localized in the lower limbs in all infected groups, worse in HAM/TSP individuals, and associated with a worse perception of quality of life. Pain was associated to higher levels of TNF-alpha and interferon-gamma. HTLV-1 pain is generally more severe when compared with other chronic pain syndromes, being present mainly in the lower limbs. Certain characteristics are typical, depending on the affected group. Oligosymptomatic and HAM/TSP individuals present more diffuse pain, with higher intensity and greater impact in quality of life. Increased levels of inflammatory cytokines are associated with HTLV-1-related pain.

Effectiveness of virtual reality games for falls, postural oscillations, pain and quality of life of individual HAM/TSP: a randomized, controlled, clinical trial.

People with HTLV-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP) have sensorimotor losses and postural instability, resulting in frequent falls. These findings stimulate the use of exercise protocols associated with postural control. This study investigated the effectiveness of a balance training exercise protocol through a virtual game. This is a randomized crossover clinical trial performed in subjects with imbalance disorders (HAM/TSP). To evaluate postural oscillations by baropodometry (total area, anterior, posterior and lateral projection), the Footwork® system was used and by cinemetry (angle of the body, hip and ankle alignment in the lateral view), the CVMob system. In addition, the Brief Pain Inventory and the WHOQoL Bref were used to measure pain intensity and quality of life. Comparison tests of the averages (intra and inter groups) and correlations were applied considering an alpha of 5% and power of 80%. The study was approved by the Ethics Committee of the Catholic University of Salvador and registered in the Clinical Trials database (NCT02877030). The final sample consisted of 26, predominantly female subjects. An increase in the postural oscillations of the control subjects (p < 0.05), a reduction in the occurrence of falls (p = 0.039) and an improvement in the quality of life of the control-test group (p < 0.05) were observed. Virtual game training did not improve the static balance, promoting an increase in postural oscillations. Immediately after the application of the protocol, there was a reduction in fall occurrence and improvement in the quality of life.

Beyond the target area: an integrative view of tDCS-induced motor cortex modulation in patients and athletes.

Transcranial Direct Current Stimulation (tDCS) is a non-invasive technique used to modulate neural tissue. Neuromodulation apparently improves cognitive functions in several neurologic diseases treatment and sports performance. In this study, we present a comprehensive, integrative review of tDCS for motor rehabilitation and motor learning in healthy individuals, athletes and multiple neurologic and neuropsychiatric conditions. We also report on neuromodulation mechanisms, main applications, current knowledge including areas such as language, embodied cognition, functional and social aspects, and future directions. We present the use and perspectives of new developments in tDCS technology, namely high-definition tDCS (HD-tDCS) which promises to overcome one of the main tDCS limitation (i.e., low focality) and its application for neurological disease, pain relief, and motor learning/rehabilitation. Finally, we provided information regarding the Transcutaneous Spinal Direct Current Stimulation (tsDCS) in clinical applications, Cerebellar tDCS (ctDCS) and its influence on motor learning, and TMS combined with electroencephalography (EEG) as a tool to evaluate tDCS effects on brain function.

Low-frequency rTMS in the superior parietal cortex affects the working memory in horizontal axis during the spatial task performance.

Spatial working memory has been extensively investigated with different tasks, treatments, and analysis tools. Several studies suggest that low frequency of the repetitive transcranial magnetic stimulation (rTMS) applied to the parietal cortex may influence spatial working memory (SWM). However, it is not yet known if after low-frequency rTMS applied to the superior parietal cortex, according to Pz electroencephalography (EEG) electrode, would change the orientation interpretation about the vertical and horizontal axes coordinates in an SWM task. The current study aims at filling this gap and obtains a better understanding of the low-frequency rTMS effect in SWM. In this crossover study, we select 20 healthy subjects in two conditions (control and 1-Hz rTMS). The subjects performed an SWM task with two random coordinates. Our results presented that low-frequency rTMS applied over the superior parietal cortex may influence the SWM to lead to a larger distance of axes interception point (p < 0.05). We conclude that low-frequency rTMS over the superior parietal cortex (SPC) changes the SWM performance, and it has more predominance in horizontal axis.

Electromyographic Biofeedback in Motor Function Recovery After Peripheral Nerve Injury: An Integrative Review of the Literature.

Electromyographic biofeedback (EMG-BF) has been applied to treat different types of peripheral nerve injuries (PNI). However, despite the clinical practice widespread use its evidence is controversial. With the objective of summarize the available evidence on the electromyographic biofeedback effectiveness and efficacy to help motor function recovery after PNI an integrative review was performed. A secondary objective was to identify the conceptual framework and strategies of EMG-BF intervention, and the quality of technical description of EMG-BF procedures. To conduct this integrative review a systematic search of the literature was performed between October 2013 and July 2018, in PUBMED, ISI and COCHRANE databases for EMG-BF original studies in PNI patients of any etiology, in English, Portuguese, Spanish or French, published after 1990. Exclusion criteria were poor description of EMG-BF treatment, associated treatment that could impair EMG-BF effect, inclusion of non-PNI individuals and case studies design. The PEDro scale was used to evaluate study quality of randomized clinical trials (RCTs) included. This resulted in 71 potential articles enrolled to full reading, although only nine matched the inclusion criteria. PNI included facial paralysis, acute sciatic inflammation and carpal tunnel syndrome. The average quality score of the included RCTs was five, corresponding to low methodological quality. Due to the small number of included articles, low quality studies and heterogeneity of interventions, outcomes and population we concluded that there is limited evidence of EMG-BF effectiveness and efficacy for motor function recovery in PNI patients.

Does Transcranial Direct Current Stimulation reduce central and peripheral muscle fatigue in recreational runners? A triple-blind, sham-controlled, randomized, crossover clinical study.

BACKGROUND: Runners seek health benefits and performance improvement. However, fatigue might be considered a limiting factor. Transcranial Direct Current Stimulation (tDCS) has been investigated to improve performance and reduce fatigue in athletes. While some studies showing that tDCS may improve a variety of physical measures, other studies failed to show any benefit. OBJECTIVE: To evaluate the acute effects of tDCS on central and peripheral fatigue compared to a sham intervention in recreational runners. METHODS: This is a triple-blind, controlled, crossover study of 30 recreational runners who were randomized to receive one of the two interventions, anodal or sham tDCS, after the fatigue protocol. The interventions were applied to the quadriceps muscle hotspot for 20 min. Peak torque, motor-evoked potential, and perceived exertion rate were assessed before and after the interventions, and blood lactate level was assessed before, during, and after the interventions. A generalized estimated equation was used to analyze the peak torque, motor-evoked potential, and blood lactate data, and the Wilcoxon test was used for perceived exertion rate data. RESULTS: Our findings showed no difference between anodal tDCS and sham tDCS on peak torque, motor-evoked potential, blood lactate, and perceived exertion rate. CONCLUSION: The tDCS protocol was not effective in improving performance and reducing fatigue compared to a sham control intervention. BRAZILIAN CLINICAL TRIALS REGISTRY: RBR-8zpnxz.

Impact of Transcranial Direct Current Stimulation in Pain, Fatigue, and Health Quality of Life of Patients with Idiopathic Inflammatory Myopathies: A Randomized, Double-Blind, Sham-Controlled Crossover Clinical Trial.

Objectives: To assess the effectiveness of transcranial direct current stimulation (tDCS) for pain, fatigue, physical function, and health-related quality of life in patients with idiopathic inflammatory myopathy (IIM). Methods: This randomized, double-blind, sham-controlled, crossover clinical trial enrolled IIM patients with fatigue and pain who received tDCS (20 min, 2 mA) or sham stimulation for 10 daily sessions. Electrodes were placed according to the 10/20 EEG system. Both the groups underwent aerobic exercise training during the intervention period. The patients were evaluated for disease perception, pain, and fatigue using uni-multidimensional questionnaires and physical tests in the periods before and after the first and second interventions and after 12 weeks of follow-up. Results: After the tDCS intervention, a reduction in the general score of multidimensional pain of 32.0 (1.5-38.0) vs. 0.0 (0.0-13.4) with effect size (ES) of -0.78 was noted, and after sham intervention, a reduction of 26.0 (0.0-37.0) vs. 5.0 (0.0-19.2) with ES of -0.54 (P = 0.047) was also noted. Similar results were evidenced with fatigue (22.5 (15.4-33.2) vs. 5.5 (0.0-14.6) with ES of -0.82) and sham intervention (21.0 (15.8-29.5) vs. 4.0 (4.0-17.5) with ES of -0.80 (P = 0.012)). There were no differences in the domains of the fatigue and pain questionnaires. Adherence was observed in 88.8% of the patients without adverse events. Conclusion: The association of tDCS with aerobic training promoted additional effects in relation to the group subjected to placebo stimulation on general pain and fatigue scores, as well as on pain intensity, without changes in the subdomains of the pain and fatigue questionnaire. This trial is registered with NCT04678635.

Sickle cell disease chronic joint pain: Clinical assessment based on maladaptive central nervous system plasticity.

Chronic joint pain (CJP) is among the significant musculoskeletal comorbidities in sickle cell disease (SCD) individuals. However, many healthcare professionals have difficulties in understanding and evaluating it. In addition, most musculoskeletal evaluation procedures do not consider central nervous system (CNS) plasticity associated with CJP, which is frequently maladaptive. This review study highlights the potential mechanisms of CNS maladaptive plasticity related to CJP in SCD and proposes reliable instruments and methods for musculoskeletal assessment adapted to those patients. A review was carried out in the PubMed and SciELO databases, searching for information that could help in the understanding of the mechanisms of CNS maladaptive plasticity related to pain in SCD and that presented assessment instruments/methods that could be used in the clinical setting by healthcare professionals who manage chronic pain in SCD individuals. Some maladaptive CNS plasticity mechanisms seem important in CJP, including the impairment of pain endogenous control systems, central sensitization, motor cortex reorganization, motor control modification, and arthrogenic muscle inhibition. Understanding the link between maladaptive CNS plasticity and CJP mechanisms and its assessment through accurate instruments and methods may help healthcare professionals to increase the quality of treatment offered to SCD patients.

Electroacupuncture modulates cortical excitability in a manner dependent on the parameters used.

INTRODUCTION: There is evidence that electroacupuncture (EA) acts through the modulation of brain activity, but little is known about its influence on corticospinal excitability of the primary motor cortex (M1). OBJECTIVE: To investigate the influence of EA parameters on the excitability of M1 in healthy individuals. METHODS: A parallel, double blind, randomized controlled trial in healthy subjects, evaluating the influence of an EA intervention on M1 excitability. Participants had a needle inserted at LI4 in the dominant hand and received electrical stimulation of different frequencies (10 or 100 Hz) and amplitude (sensory or motor threshold) for 20 min. In the control group, only a brief (30 s) electrical stimulation was applied. Single and paired pulse transcranial magnetic stimulation coupled with electromyography was applied before and immediately after the EA intervention. Resting motor threshold, motor evoked potential, short intracortical inhibition and intracortical facilitation were measured. RESULTS: EA increased corticospinal excitability of M1 compared to the control group only when administered with a frequency of 100 Hz at the sensory threshold (p < 0.05). There were no significant changes in the other measures. CONCLUSION: The results suggest that EA with an intensity level at the sensorial threshold and 100 Hz frequency increases the corticospinal excitability of M1. This effect may be associated with a decrease in the activity of inhibitory intracortical mechanisms. TRIAL REGISTRATION NUMBER: U1111-1173-1946 (Registro Brasileiro de Ensaios Clínicos; http://www.ensaiosclinicos.gov.br/).

Influence of surface peripheral electrical stimulation on nerve regeneration after digital nerve neurorrhaphy: study protocol for a randomized clinical trial.

We will study the influence of low intensity and frequency surface peripheral electrical stimulation (PES) on nerve regeneration of digital nerve injuries of the hand after its surgical repair in humans. Participants will be patients with acute traumatic peripheral nerve injury referred to the Hand Surgery Service of the General Hospital of the State of Bahia, a reference service in the state. These patients will undergo surgery followed by PES in the immediate postoperative period. After hospital discharge, they will be followed up on an outpatient basis by researchers, who will remotely supervise a physiotherapy program. Our hypothesis is that PES will positively influence the recovery of sensory function in patients undergoing neurorrhaphy of digital nerves of the hand. ReBEC registration:  U1111-1259-1998 (12/18/2020).

Closed-loop neurostimulation for affective symptoms and disorders: An overview.

Affective and anxiety disorders are the most prevalent and incident psychiatric disorders worldwide. Therapeutic approaches to these disorders using non-invasive brain stimulation (NIBS) and analogous techniques have been extensively investigated. In this paper, we discuss the combination of NIBS and neurofeedback in closed-loop setups and its application for affective symptoms and disorders. For this, we first provide a rationale for this combination by presenting some of the main original findings of NIBS, with a primary focus on transcranial magnetic stimulation (TMS), and neurofeedback, including protocols based on electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Then, we provide a scope review of studies combining real-time neurofeedback with NIBS protocols in the so-called closed-loop brain state-dependent neuromodulation (BSDS). Finally, we discuss the concomitant use of TMS and real-time functional near-infrared spectroscopy (fNIRS) as a possible solution to the current limitations of BSDS-based protocols for affective and anxiety disorders.

Impact of neuropathic pain on quality of life in adults with sickle cell disease: observational study.

INTRODUCTION: Knowledge on the characteristics of neuropathic pain in people with sickle cell disease (SCD) may help to provide more effective treatment procedures. OBJECTIVE: To describe the characteristics of neuropathic pain in patients with sickle cell disease and identify the impact on their quality of life. METHOD: A cross-sectional study (CAAE 57274516.8.0000.5544) was conducted at a reference center in Salvador, Bahia, Brazil. The instruments used were the Brief Pain Inventory (BPI), the Douleur Neuropatique Questionnaire (DN-4), the Anxiety and Depression Hospital scale (ADH) and the abbreviated version of the World Health Organization of Quality of Life questionnaire (WHOQOL-brief). The Mann-Whitney test was used to evaluate the association between the scores (5% alpha). RESULTS: A total of 100 adults with SCD participated in the study, 69.7% of whom had neuropathic pain. Anxiety was present in 99% of the sample and depression, in 100%. Patients with neuropathic pain had worse scores in all domains of quality of life (p < 0.05), but no association was found with pain intensity. CONCLUSION: Neuropathic pain was more frequent than nociceptive pain in adults with SCD and generated worse scores in all domains of quality of life. Anxiety and depression were present in patients with both types of pain.

Brazilian research on noninvasive brain stimulation applied to health conditions.

BACKGROUND: Brazil has a top position regarding scientific production on noninvasive neuromodulation worldwide. Knowledge of scientometric phenomena involving Brazilian researchers who produce science on this theme may aid confidence in Brazilian clinical and research professionals. OBJECTIVE: To investigate the scenario of research on the theme of noninvasive neuromodulation in Brazil. METHODS: This was a scientometric study for mapping scientific production on this subject involving network phenomena, the professions of researchers, institutional affiliation, main research unit, total number of scientific articles on noninvasive neuromodulation published in journals, research sub-area and year of obtaining the PhD title. Public data from Lattes Platform curricula vitae and from VOSViewer© were used. RESULTS: A total of 54 Brazilian researchers were identified, of whom 16 are research productivity fellows. Most of them are linked to institutions in southeastern Brazil, involving the professions of biology, biochemistry, physical education, physiotherapy, speech therapy, gerontology, medicine and psychology, with 1175 articles published in journals. These studies involve experimental animal and human models to account for mechanisms, observational studies, case reports, randomized clinical trials, systematic reviews, meta-analyses, product and process development, computer modeling and guidelines. CONCLUSIONS: Brazil occupies a prominent place in the world scenario of research on noninvasive neuromodulation, which is used by different professions for treatment of brain dysfunctions, with a trend towards expansion to other fields.

Alternate sessions of transcranial direct current stimulation (tDCS) reduce chronic pain in women affected by chikungunya. A randomized clinical trial.

CONTEXT: Thousands of people worldwide have been infected by the chikungunya virus (CHIKV), and the persistence of joint pain symptoms has been considered the main problem. Neuromodulation techniques such as transcranial direct current stimulation (tDCS) act on brain areas involved in the processing of chronic pain. It was previously demonstrated that tDCS for five consecutive days significantly reduced pain in the chronic phase of chikungunya (CHIK). OBJECTIVE: To analyze the effect of alternate tDCS sessions on pain and functional capacity in individuals affected by CHIK. METHODS: In a randomized clinical trial, 58 women in the chronic phase of CHIK were divided into two groups: active-tDCS (M1-S0, 2 mA, 20 min) and sham-tDCS. The Visual Analogue Scale (VAS) and the Brief Pain Inventory (BPI) were used to assess pain, while the Health Assessment Questionnaire (HAQ) assessed functional capacity. These scales were used before and after six sessions of tDCS in nonconsecutive days on the primary motor cortex, and at follow-up consultation 7 and 15 days after the last session. A repeated measures mixed-model ANOVA was used for comparison between groups (significant p-values < 0.05). RESULTS: A significant pain reduction (Z [3, 171] = 14.303; p < 0.0001) was observed in the tDCS group compared to the sham group; no significant difference in functional capacity was observed (Z [1.57] = 2.797; p = 0.1). CONCLUSION: Our results suggest that six nonconsecutive sessions of active tDCS on M1 reduce pain in chronic CHIKV arthralgia.

Noninvasive Neuromodulation Techniques in Difficult Tracheostomy Weaning of Patients With Spinal Cord Injury: Report of Two Cases.

High spinal cord injured patients (SCI) are susceptible to respiratory muscle impairments. Transcranial direct current stimulation (tDCS) and peripheral electrical stimulation (PES) may influence the diaphragm's central control, but until now they are not described as a therapeutic resource for difficult weaning. We present two case reports of SCI patients (P1 and P2) with long-term tracheostomy (>40 days) and hospital stay (>50 days). In association with respiratory exercise, P1 received a combined application of anodal tDCS over the supplementary motor area plus sensory PES in the thoracic-abdominal muscles, and P2 received isolated excitatory PES in the abdominal muscles, applied daily except on weekends. Maximum inspiratory/expiratory pressure, peak cough flow, diaphragm excursion, and thickening fraction were measured in the first and last days of the protocol. Both patients had improvements, with clinical impact such as cough effectiveness, decannulated after 15 applications of stimulation. Augmentation of neural respiratory drive and corticospinal excitability is suggested.

Effects of transcranial direct current stimulation on heart rate variability: a systematic review protocol.

OBJECTIVE: This systematic review aims to synthesize the available evidence on the effects of transcranial direct current stimulation on heart rate modulation, indexed by heart rate variability parameters in healthy individuals and those with clinical disorders. INTRODUCTION: There is some evidence that altered heart rate variability parameters are associated with different clinical disorders. For example, diminished parasympathetic activity has been explored as a potential biomarker for some chronic pain conditions. Considering the dynamic interaction between brain and heart, neuromodulatory strategies targeting this relationship could exert a positive influence on the cardiac autonomic system. Transcranial direct current stimulation is a non-invasive neuromodulation technique that has been presenting recent advances in the treatment of various clinical disorders. However, the evidence concerning transcranial direct current stimulation application focusing on brain-heart interaction is still controversial. INCLUSION CRITERIA: This review will consider studies that investigate the effects of transcranial direct current stimulation on heart rate variability in healthy participants or those with clinical disorders. METHODS: This review will follow JBI systematic review methodology recommendations. PubMed, Embase, CINAHL, Web of Science, PsycNET, Cochrane Controlled Register of Trials (CENTRAL) and Physiotherapy Evidence Database (PEDro) will be searched, along with several sources of gray literature. Retrieval of full-text studies, and assessment of methodological quality and data extraction, will be performed independently by two reviewers. Data will be pooled in statistical meta-analysis, where possible. SYSTEMATIC REVIEW REGISTRATION NUMBER: PROSPERO CRD42018114105.

Balance assessment in HTLV-1 associated myelopathy or tropical spastic paraparesis.

INTRODUCTION: A good rating of the device in people with HTLV-1 in this population is essential for accuracy in prescribing data (walking). Thus, this study aimed to analyze the counterpart assessment methods that are best suited to patients with human T-cell lymphotropic virus (HTLV)-1 associated myelopathy or tropical spastic paraparesis (HAM/TSP). METHODS: This cross-sectional study related stabilometric and kinematic variables of postural oscillations with Berg's balance scale (BBS) and Timed Up and Go (TUG) in subjects with HAM/TSP compared to asymptomatic subjects. To assess the posterior and lateral postural projection, baropodometry and the Footwork® system was used, and the CVMob system was applied to kinematic parameters. The means comparison tests and correlations were applied with an alpha of 5%. RESULTS: Thirty-nine subjects (predominantly female) made up the sample. There was an increase in barodopometric oscillations, in the total oscillation area (p = 0.004), in the anteroposterior oscillation in the left (p = 0.015) and right views (p = 0.036), and in the lateral oscillation (p = 0.039) in the HAM/TSP group. Moderate correlations were found between oscillation baropodometry and the angular variation of the ankle, as well as with the BBS in the three angles and the TUG for lateral oscillation (p = 0.406). CONCLUSIONS: Each method has advantages and disadvantages, including cost accuracy. The best resources available at no additional cost for outpatient to use are the kinematic evaluation using a simple smartphone camera and free analysis software, and the TUG.

The effect of home exercise on the posture and mobility of people with HAM/TSP: a randomized clinical trial.

BACKGROUND: Physical therapy has positive results in people with tropical spastic paraparesis (TSP). However, mobility and distance from rehabilitation centers limit the participation in outpatient programs. OBJECTIVE: To evaluate the impact of a home exercise program on the posture and functional mobility of people with TSP. METHODS: A randomized controlled trial comparing three groups of people who performed guided exercises from a guidebook for six months: supervised (SG), unsupervised (WG), and control (CG). Primary outcomes: postural angles (SAPO®) and functional mobility (TUG). SECONDARY OUTCOMES: gait parameters (CVMob®). RESULTS: The protocol described in the guidebook improved postural angles and functional mobility. There were also positive gait parameter effects (p<0.05). SG presented better responses than WG did, but both were preferable to CG. CONCLUSION: Home exercises oriented by a guidebook may benefit posture, functional mobility and gait parameters in people with TSP, and physiotherapist supervision can ensure better results.

Pharmacological treatment of central neuropathic pain: consensus of the Brazilian Academy of Neurology.

BACKGROUND: Central neuropathic pain (CNP) is often refractory to available therapeutic strategies and there are few evidence-based treatment options. Many patients with neuropathic pain are not diagnosed or treated properly. Thus, consensus-based recommendations, adapted to the available drugs in the country, are necessary to guide clinical decisions. OBJECTIVE: To develop recommendations for the treatment of CNP in Brazil. METHODS: Systematic review, meta-analysis, and specialists opinions considering efficacy, adverse events profile, cost, and drug availability in public health. RESULTS: Forty-four studies on CNP treatment were found, 20 were included in the qualitative analysis, and 15 in the quantitative analysis. Medications were classified as first-, second-, and third-line treatment based on systematic review, meta-analysis, and expert opinion. As first-line treatment, gabapentin, duloxetine, and tricyclic antidepressants were included. As second-line, venlafaxine, pregabalin for CND secondary to spinal cord injury, lamotrigine for CNP after stroke, and, in association with first-line drugs, weak opioids, in particular tramadol. For refractory patients, strong opioids (methadone and oxycodone), cannabidiol/delta-9-tetrahydrocannabinol, were classified as third-line of treatment, in combination with first or second-line drugs and, for central nervous system (CNS) in multiple sclerosis, dronabinol. CONCLUSIONS: Studies that address the treatment of CNS are scarce and heterogeneous, and a significant part of the recommendations is based on experts opinions. The CNP approach must be individualized, taking into account the availability of medication, the profile of adverse effects, including addiction risk, and patients' comorbidities.