Motor cortex transcranial direct current stimulation effects on knee osteoarthritis pain in elderly subjects with dysfunctional descending pain inhibitory system: A randomized controlled trial

The effects of various physical modalities on pain in patients with knee osteoarthritis: A network meta-analysis

Objective

This study aims to evaluate the effectiveness of various physical therapy methods in reducing pain for patients with knee osteoarthritis (KOA) through a network meta-analysis.

Methods

We conducted a comprehensive search across multiple databases, including PubMed, Embase, Cochrane Library, VIP, WanFang Data, and CNKI, to identify randomized controlled trials (RCTs) on physical therapies for KOA. The search spanned from the inception of each database to October 2024. The methodological quality of the studies was assessed using the Cochrane Handbook. Pain was measured using tools such as the visual analog scale, numeric pain rating scale, and the Western Ontario and McMaster University Osteoarthritis Index. All pain scores were standardized to a 10-point scale. Data collection and analysis were performed independently by two researchers using Stata 15.0 software.

Results

The analysis included 64 studies with 3855 patients and 12 physical therapy modalities. Based on the surface under the cumulative ranking curve (SUCRA), the most effective treatments were HILT, ESWT, Hydrotherapy, Land-EX, LLLT, Braces, tDCS, US, IFCs, SWD, Insoles, and TENS.

Conclusion

HILT appears to be the most effective treatment for pain relief in KOA patients. Further large-scale RCTs are needed to confirm these findings.

The effects of combined transcranial direct Current stimulation with physiotherapy for physical function in subjects with knee osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Transcranial Direct Current Stimulation (tDCS) emerges as a promising therapeutic intervention for knee osteoarthritis (KOA), yet its impact on physical function remains insufficiently explored.

OBJECTIVES

To evaluate the relative effects of tDCS for physical function in patients with KOA.

METHODS

Pubmed, Web of Science, Scopus and Cochrane Database were explored as of August 2023 to identify studies to be included in the current systematic review and metaanalysis. Randomized controlled trials in patients with KOA comparing tDCS with placebo were included. The outcomes defined were measures of physical function (questionnaires, gait, or physical performance). The Risk of Bias tool was used to assess bias in the randomized controlled trials, whereas the PEDro scale was applied for methodological quality, and the certainty of evidence for each outcome was assessed through GRADE. Results for each outcome were synthesized using meta-analysis (random-effects model, I2-test for heterogeneity) and a subgroup analysis was performed to improve the sensitivity of the results and to explore potential moderating factors of the effect sizes.

RESULTS

Ten studies with good to excellent quality were included, analyzing a total of 628 participants. Regarding physical function, tDCS showed a favorable effect (ES: -0.58; 95%CI -0.82, -0.33; I2: 52.1%) with a low risk of bias and low to moderate certainty of evidence. The concurrent application of physiotherapy interventions and tDCS improved the effects on pain and function. Applying physiotherapy interventions, as well as adding peripheral currents, increased the effect sizes (ES: -0.95, k = 3, p = .018; ES: -0.95, k = 4 p = .001, respectively). The pattern of application of the tDCS, either daily or in alternate days, did not moderate the effect size (p = .619). Meta-regression revealed that the number of tDCS sessions did not moderate the effect size either (p = .242).

CONCLUSION

The tDCS might be a promising therapeutic approach to enhance physical function in subjects affected with KOA. However, further systematic reviews with meta-analyses should be performed with standardized and proven-efficacy physiotherapy programs, as well as with long-term results, to ascertain whether the improvement may be sustained over time. This study provides valuable insights into optimizing tDCS interventions for enhanced outcomes in the management of KOA.Protocol available via PROSPERO [CRD42023440676].

Bone-brain crosstalk in osteoarthritis: pathophysiology and interventions

Osteoarthritis (OA) is a prevalent articular disorder characterized by joint degeneration and persistent pain; it imposes a significant burden on both individuals and society. While OA has traditionally been viewed as a localized peripheral disorder, recent preclinical and clinical studies have revealed the crucial interconnections between the bone and the brain, highlighting the systemic nature of OA. The neuronal pathway, molecular signaling, circadian rhythms, and genetic underpinnings within the bone-brain axis play vital roles in the complex interplay that contributes to OA initiation and progression. This review explores emerging evidence of the crosstalk between the bone and brain in OA progression, and discusses the potential contributions of the bone-brain axis to the development of effective interventions for managing OA.

Transcranial direct current stimulation alleviates the pain severity in people suffering from knee osteoarthritis: a systematic review and meta-analysis

Considerable research has shown the benefits of transcranial direct current stimulation (tDCS) for the alleviation of pain associated with knee osteoarthritis (KOA). Still, a large variance in study protocols and observations across publications exists. We here thus completed a systematic review and meta-analysis to comprehensively and quantitatively characterize the effects of tDCS on KOA-related pain. A search strategy based on the Population, Intervention, Comparison, Outcome, and Study design (PICOS) principle was used to obtain the publications in 7 databases. Studies exploring the effects of tDCS on KOA-related pain were screened, and eligible studies were included. Ten studies of 518 participants using Visual Analogue Scale or Numeric Rating Scale to assess pain were included in the systematic review, and 9 of them were included in meta-analysis. The quality of these studies was good. Compared to control, tDCS induced significant short-term improvements in KOA-related pain with medium heterogeneity (standardized mean difference [SMD] = -0.91, 95% confidence interval [-1.24, -0.58], P < 0.001, I2 = 61%). Subgroup analyses showed that both home-based (SMD = -1.32, 95% CI [-1.65, -0.99], P < 0.001, I 2 = 0%) and laboratory-based intervention (SMD = -0.66, 95% CI [-0.99, -0.33], P < 0.001, I 2 = 40%) with at least 5 sessions per week (SMD = -1.02, 95% CI [-1.41, -0.64], P < 0.001, I 2 = 65%) and/or with a total number of at least 10 sessions (SMD = -1.12, 95% CI [-1.51, -0.74], P < 0.001, I 2 = 59%) can induce maximum benefits for the alleviation of KOA-related pain. The results here showed that tDCS is of great promise to alleviate KOA-related pain. Still, future studies with more rigorous design are needed to confirm the observations from this work, which can ultimately help the determination of appropriate intervention protocol that can maximize such benefits.

Factors, characteristics and influences of the changes of muscle activation patterns for patients with knee osteoarthritis: a review

BACKGROUND

Knee Osteoarthritis (KOA) is a prevalent condition worldwide, significantly diminishing quality of life and productivity. Except for the alignment change, muscle activation patterns (MAP) have garnered increasing attention as another crucial factor contributing to KOA.

OBJECTIVE

This study explores the factors, characteristics, and effects of MAP changes caused by KOA, providing a neuromuscular-based causal analysis for the rehabilitation treatment of KOA.

METHODS

Keywords including the association of MAP with KOA will be included. "Knee, Osteoarthritis, Electromyography(EMG), Muscle Activity patterns, activation amplitudes, activation time, Muscle Synergy, Co-contraction/activation" were used to search the databases of Science Direct, PubMed, Scopus, and Wiley. The criteria include studies from the past fifteen years that document changes in muscle contraction characteristics and causality analysis in patients with KOA. we compared MAP changes between individuals with and without KOA, such as the activation amplitudes, activation time, muscle synergy and co-contraction index(CCI). Additionally, we explored the potential relationship between muscle weakness, pain, and lower limb mechanical changes with the variations of MAP.

RESULTS

A total of 832 articles were reviewed, and 44 articles that met the inclusion criteria were selected for analysis. The changes in biomechanical structure, pain, and muscle atrophy may contribute to the formation and progression of the changes in MAP in KOA patients. In moderate KOA patients, the vastus lateralis (VL) and biceps femoris (BF) exhibits larger activation amplitudes, with earlier and longer activation times. The vastus medialis (VM) shows a delayed activation time relative to VL. Gastrocnemius activation time is prolonged during mid-gait, while the soleus exhibits lower activation amplitudes during the late stance phase. There are fewer, merged synergies with prolonged activation coefficients, and a higher percentage of unclassifiable synergies. Additionally, the CCI is positively correlated with task difficulty and symptoms. It is higher in the medial and lateral than hamstrings and quadriceps, and CCI specifically respond to joint stabilisation and load.

CONCLUSION

In patients with moderate KOA, changes in MAP are mainly related to symptoms and the difficulty of tasks. MAP changes primarily result in variations in amplitude, contraction duration, muscle synergy, and CCI. The MAP changes can subsequently affect the intermuscular structure, pain, joint loading, and stiffness.

CLINICAL IMPLICATIONS

These contribute to the progression of KOA and create a vicious cycle that accelerates disease advancement. Clinical rehabilitation treatments can target the MAP changes to break the cycle and help mitigate disease progression.

Anodal transcranial direct current stimulation (tDCS) modulates quadriceps motor cortex inhibition and facilitation during rehabilitation following anterior cruciate ligament (ACL) reconstruction: a triple-blind, randomised controlled proof of concept trial

Objectives

Following anterior cruciate ligament reconstruction (ACLR), maladaptive changes occur in the motor cortex representation of the quadriceps, evidenced by increases in intracortical inhibition and facilitation. The primary objective of this proof-of-concept study was to determine if anodal transcranial direct current stimulation (tDCS) can alter quadriceps intracortical inhibition and facilitation in an early-ACLR population after 6 weeks of application during exercise.

Methods

We performed a randomised, triple-blind controlled trial for proof of concept comparing anodal-tDCS to sham-tDCS following ACLR. Anodal-tDCS or sham-tDCS was delivered to the primary motor cortex for 20 min, three times per week, for 6 weeks from week 2 post ACLR. Transcranial magnetic stimulation quantified quadriceps short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI) and short-interval intracortical facilitation (SICF). Significance at p<0.05.

Results

Participants were randomised to anodal (n=11) or sham (n=10) tDCS. Participants were predominantly male (n=13) and had a mean (SD) age of 24.4 (4.7) years. For SICI, there was a group-by-time effect for anodal-tDCS (β=0.519, 95% CI 0.057 to 0.981, p=0.028) and an effect for time (β=-1.421, 95% CI -1.919 to -0.923, p<0.001). For LICI, there was no group-by-time (β=-0.217, 95% CI -0.916 to 0.482, p=0.543) or time effect (β=0.039, 95% CI -0.815 to -0.893, p=0.928). For SICF, there was a group-by-time effect for anodal-tDCS (β=-0.764, 95%CI -1.407 to -0.120, p=0.020) but not time (β=0.504, 95% CI -0.627 to 1.635, p=0.383).

Conclusion

This study provided proof of the efficacy of anodal-tDCS post ACLR in reducing maladaptive quadriceps inhibition and facilitation. We demonstrated anodal-tDCS improved facilitation and inhibition post ACLR, which are drivers of arthrogenic muscle inhibition.

Effects of transcranial direct current stimulation on pain and physical function in patients with knee osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Keen Osteoarthritis (KOA) is a common chronic disabling disease characterized by joint pain and dysfunction, which seriously affects patients' quality of life. Recent studies have shown that transcranial direct current stimulation (tDCS) was a promising treatment for KOA.

PURPOSE

Investigate the effects of tDCS on pain and physical function in patients with KOA.

METHODS

Randomized controlled trials related to tDCS and KOA were systematically searched in the PubMed, Embase, Medline, Cochrane Library, CINHL, and Web of Science databases from inception to July 23, 2024. The pain intensity was evaluated using the visual analog scale or the numeric rating scale, and the pain sensitivity was assessed using conditioned pain modulation, pressure pain threshold, heat pain threshold, or heat pain tolerance. The physical function outcome was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index or the Knee injury and Osteoarthritis Outcome Score. Statistical analysis was performed using Review Manager 5.4.

RESULTS

Seven studies with a total of 503 participants were included. Compared to sham tDCS, tDCS was effective in reducing the short-term pain intensity (SMD: -0.58; 95% CI: -1.02, -0.14; p = 0.01) and pain sensitivity (SMD: -0.43; 95% CI: -0.70, -0.16; p = 0.002) but failed to significantly improve the long-term pain intensity (SMD: -0.26; 95% CI: -0.59, 0.08; p = 0.13) in KOA patients. In addition, tDCS did not significantly improve the short-term (SMD: -0.13; 95% CI: -0.35, 0.08; p = 0.22) and long-term (SMD: 0.02; 95% CI: -0.22, 0.25; p = 0.90) physical function in patients with KOA.

CONCLUSIONS

The tDCS can reduce short-term pain intensity and sensitivity but fails to significantly relieve long-term pain intensity and improve the physical function in patients with KOA. Thus, tDCS may be a potential therapeutic tool to reduce short-term pain intensity and pain sensitivity in patients with KOA.

Comparison of responders and nonresponders with knee osteoarthritis after transcranial direct current stimulation

AIM

The study compared responders and nonresponders to transcranial direct current stimulation (tDCS) regarding clinical pain outcomes in knee osteoarthritis (OA) patients.

PATIENTS AND METHODS/MATERIALS

Sixty participants received home-based active tDCS, and clinical pain outcomes were compared between responders and nonresponders.

RESULTS

Latent class growth analyses classified 41 participants as responders and 19 as nonresponders. Responders showed significantly greater decreases in pain intensity from baseline to post intervention than nonresponders (p < .001). Participants with higher BMI (p = .02) and weight (p = .005) were more likely to respond, while no significant sociodemographic differences were found.

CONCLUSIONS

Identifying characteristics of nonresponsive tDCS subgroups can tailor treatments for each group.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT04016272.

Associations of pain sensitivity and conditioned pain modulation with physical activity: findings from the Multicenter Osteoarthritis Study (MOST)

OBJECTIVE

Individuals with chronic pain due to knee osteoarthritis (OA) are insufficiently physically active, and alterations of facilitatory and inhibitory nociceptive signaling are common in this population. Our objective was to examine the association of these alterations in nociceptive signaling with objective accelerometer-based measures of physical activity in a large observational cohort.

DESIGN

We used data from the Multicenter Osteoarthritis Study. Measures of peripheral and central pain sensitivity included pressure pain threshold at the knee and mechanical temporal summation at the wrist, respectively. The presence of descending pain inhibition was assessed by conditioned pain modulation (CPM). Physical activity was quantitatively assessed over 7 days using a lower back-worn activity monitor. Summary metrics included steps/day, activity intensity, and sedentary time. Linear regression analyses were used to evaluate the association of pain sensitivity and the presence of descending pain inhibition with physical activity measures.

RESULTS

Data from 1873 participants was analyzed (55.9% female, age = 62.8 ± 10.0 years). People having greater peripheral and central sensitivity showed lower step counts. CPM was not significantly related to any of the physical activity measures, and none of the exposures were significantly related to sedentary time.

CONCLUSIONS

In this cohort, greater peripheral and central sensitivity were associated with reduced levels of objectively-assessed daily step counts. Further research may investigate ways to modify or treat heightened pain sensitivity as a means to increase physical activity in older adults with knee OA.

Maximising neuromuscular performance in people with pain and injury: moving beyond reps and sets to understand the challenges and embrace the complexity

Rehabilitative practice is often criticised for being non-individualised, monotonous and not well aligned with foundational principles that drive continued physiological adaptation(s). However, our understanding of neuromuscular physiology is rapidly increasing and the way we programme rehabilitation is improving. This viewpoint highlights some of the potential considerations around why the adaptations achieved during rehabilitation programmes may be suboptimal. We provide basic, clinician-focused discussion about potential confounding physiological factors, and put forward several exercise-based programming recommendations and novel approaches to consider in contemporary rehabilitative practice. Specifically, we outline several potential mechanisms contributing to poor muscle activation and function that might be present following musculoskeletal injury. However, clinicians require strategies capable of attenuating these impairments to restore proper function. Therefore, we also provide an overview of recommended strength and conditioning guidelines, and novel strategies (such as external pacing and electrical stimulation techniques) that clinicians can consider to potentially improve the efficacy of musculoskeletal rehabilitation.

Efficacy of Transcranial Direct Current Stimulation on Pain Intensity and Functionality in Patients With Knee Osteoarthritis: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study is to investigate whether transcranial direct current stimulation is superior to control groups or other interventions for pain relief and improving functionality in knee osteoarthritis patients.

METHODS

PubMed, the Physiotherapy Evidence Database, the Cochrane Library, ProQuest, and Scopus databases were searched from inception to July 2022 to identify randomized clinical trials. The main outcomes were subjective perception of pain intensity measured either with the visual analog scale or with the numeric rating scale; and the functionality, assessed with the Western Ontario and McMaster Universities Osteoarthritis Index. As secondary outcomes, pressure pain threshold, conditioned pain modulation, and its safety were evaluated.

RESULTS

We identified 10 randomized clinical trials (634 participants). The results showed an important effect favoring transcranial direct current stimulation for pain relief (mean difference = -1.1 cm, 95% confident interval = -2.1 to -0.2) and for improving functionality (standardized mean difference = -0.6, 95% confident interval = -1.02 to -0.26). There was also a significant improvement in pressure pain threshold (mean difference = 0.9 Kgf/cm 2 , 95% confident interval = 0.1 to 1.6). The certainty of evidence according to Grades of Recommendation Assessment, Development and Evaluation was generally moderate.

CONCLUSIONS

Our findings suggest that transcranial direct current stimulation is a safe treatment for reducing pain intensity, improving functionality, and the pressure pain thresholds in patients with knee osteoarthritis.

Cross-sectional and longitudinal analysis of conditioned pain modulation and pain in fibromyalgia: CPM as an effect modifier of pain changes over time

Background and purpose

Fibromyalgia (FM) is associated with altered descending pain modulatory pathways, which can be assessed through Conditioned Pain Modulation (CPM). In this study, we aimed to explore the relationship between CPM and self-reported baseline characteristics in patients with fibromyalgia. We also performed a longitudinal analysis exploring CPM as a potential predictor of clinical improvement over time in individuals with FM.

Methods

We performed cross-sectional univariable and multivariable analyses of the relationship between CPM and other variables in 41 FM patients. We then performed longitudinal analyses, building linear mixed effects models with pain in the Visual Analogue Scale (VAS) as the dependent variable, and testing for the interaction between time and CPM. We also tested the interaction between CPM and time in models using other outcomes, such as the revised Fibromyalgia Impact Questionnaire (FIQR) and Quality of Life Scale (QOLs).

Results

We found no association between CPM and other demographic and clinical variables in the univariable analysis. We found a statistically significant association in the multivariable linear regression model between CPM and the QOLs at baseline, after controlling for age, sex, and duration of symptoms. In the longitudinal analyses, we found that CPM is an effect modifier for clinical improvement over time for the pain VAS, QOLs and FIQR: individuals with low-efficient CPM at baseline have a different (improved) pattern of response over time when compared to those with high-efficient CPM.

Conclusions

Our findings suggest that CPM is not a reliable biomarker of clinical manifestations in chronic pain patients during cross-sectional assessments. However, our results are consistent with previous findings that CPM can be used to predict the evolution of clinical pain over time. We expect that our findings will help in the selection of patients with the best profile to respond to specific interventions and assist clinicians in tailoring pain treatments.

Transcranial Direct Current Stimulation for Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The effects of transcranial direct current stimulation (tDCS) in the treatment of knee osteoarthritis (KOA) is still unclear. The objective is to evaluate the efficacy and safety of tDCS in improving symptoms in patients with KOA.

METHODS

The following electronic databases were searched for eligible randomized controlled trials (RCTs): PubMed, Embase, Web of Science, and the Cochrane Library. The search was performed from the inception dates to April 30, 2023. Data extraction and quality assessment were performed by two independent reviewers. Standard mean differences (SMDs) with 95% confidence intervals (95% CIs) for pooled data were calculated. A random-effects model was used for the data analyses. The primary outcomes were pain and physical function. Secondary outcomes included stiffness, mobility performance, quality of life, pressure pain tolerance, and plasma levels of brain-derived neurotrophic factor (BDNF).

RESULTS

This meta-analysis included 13 RCTs. tDCS was significantly associated with pain decrease compared with sham tDCS (SMD = -0.62, 95% CI -0.87 to -0.37, P < 0.00001). When comparing tDCS plus other non-tDCS with sham tDCS plus other non-tDCS, there was no longer a significant association with pain decrease (SMD = -0.45, 95% CI -1.08 to 0.17, P = 0.16). The changes in physical function were not significantly different between the tDCS and sham tDCS groups (SMD = -0.09, 95% CI -0.56 to 0.38, P = 0.71). When comparing tDCS plus other non-tDCS with sham tDCS plus other non-tDCS, there was still no significant association with improvement in physical function (SMD = -0.66, 95% CI -1.63 to 0.30, P = 0.18). There was no significant difference with improvement in stiffness (SMD = -0.21, 95% CI -0.77 to 0.34, P = 0.45), mobility performance (SMD = 4.58, 95% CI -9.21 to 18.37, P = 0.51), quality of life (SMD = -7.01, 95% CI -22.61 to 8.59, P = 0.38), and pressure pain tolerance (SMD = 0.30, 95% CI -0.09 to 0.69, P = 0.13). There was a statistically significant reduction in plasma levels of BDNF (SMD = -13.57, 95% CI -24.23 to -2.92, P = 0.01).

CONCLUSION

In conclusion, tDCS could significantly alleviate pain, but it might have no efficacy in physical function, stiffness, mobility performance, quality of life, and pressure pain tolerance among patients with KOA.

Transcranial Direct Current Stimulation for Orthopedic Pain: A Systematic Review with Meta-Analysis

(1) Background: Transcranial direct current stimulation (tDCS) appears to alleviate chronic pain via a brain-down mechanism. Although several review studies have examined the effects of tDCS on patients with chronic pain, no systematic review or meta-analysis has comprehensively analyzed the effects of tDCS on chronic orthopedic joint pain in one study. We aim to evaluate the effectiveness of tDCS for pain reduction in chronic orthopedic patients; (2) Methods: A comprehensive search of five electronic databases (Medline, Embase, Web of Science, CINAHL, and Cochrane) was performed. Only randomized controlled trials that compared tDCS with a control intervention were included. Eighteen studies met our inclusion criteria. We identified four categories of chronic orthopedic pain: knee (k = 8), lower back (k = 7), shoulder (k = 2), and orofacial pain (k = 1). Random effect models were utilized, and a sensitivity analysis was conducted in the presence of significant heterogeneity. Studies within each pain condition were further classified according to the number of treatment sessions: 1-5 sessions, 6-10 sessions, and >10 sessions.; (3) Results: Significant reductions in chronic orthopedic joint pain were observed following tDCS compared to controls for knee (g = 0.59, p = 0.005), lower back (g = 1.14, p = 0.005), and shoulder (g = 1.17, p = 0.020). Subgroup analyses showed pain reductions after 6-10 tDCS sessions for knee pain and after 1-5 and >10 sessions for lower back pain; (4) Conclusions: tDCS could be considered a potential stand-alone or supplemental therapy for chronic knee and lower back pain. The effectiveness of tDCS treatment varies depending on the number of treatment sessions. Our findings suggest the importance of implementing individualized treatment plans when considering tDCS for chronic pain conditions.

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.

Effectiveness of Transcranial Direct Current Stimulation in Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Sham-Controlled Trials

OBJECTIVE

The aim of the study is to assess the effectiveness of transcranial direct current stimulation in knee osteoarthritis.

METHODS

The study searched PubMed, Cochrane Library, Embase, and Scopus databases until August 3, 2023, and identified randomized controlled trials evaluating the effects of transcranial direct current stimulation in knee osteoarthritis whose outcomes using pain scores or functional scales. The selected randomized controlled trials were subjected to meta-analysis and risk of bias assessment.

RESULTS

Seven randomized controlled trials involving 488 patients were included in this meta-analysis. Compared with the control group, the transcranial direct current stimulation group exhibited significant improvement in pain scores after treatment (standardized mean difference = 1.03; 95% confidence interval: 0.70 to 1.35; n = 359; I2 = 46%), pain scores during follow-up (standardized mean difference = 0.83; 95% confidence interval: 0.21 to 1.45; n = 358; I2 = 86%), and Western Ontario and McMaster Universities Osteoarthritis scores after treatment (standardized mean difference = 4.76; 95% confidence interval: 0.16 to 9.53; n = 319; I2 = 74 % ), but Western Ontario and McMaster Universities Osteoarthritis scores during follow-up did not differ significantly between the groups (standardized mean difference = 0.06; 95% confidence interval: -0.2 to 0.32; n = 225; I2 = 0%).

CONCLUSIONS

Transcranial direct current stimulation is a promising therapy for knee osteoarthritis. Further investigation using large-scale, high-quality randomized controlled trials is necessary for optimal transcranial direct current stimulation approach in knee osteoarthritis.

Transcranial Direct Current Stimulation (tDCS) Effects on Quantitative Sensory Testing (QST) and Nociceptive Processing in Healthy Subjects: A Systematic Review and Meta-Analysis

BACKGROUND

The aim of this study is to determine the effect that different tDCS protocols have on pain processing in healthy people, assessed using quantitative sensory tests (QST) and evoked pain intensity.

METHODS

We systematically searched in EMBASE, CINAHL, PubMed, PEDro, PsycInfo, and Web of Science. Articles on tDCS on a healthy population and regarding QST, such as pressure pain thresholds (PPT), heat pain thresholds (HPT), cold pain threshold (CPT), or evoked pain intensity were selected. Quality was analyzed using the Cochrane Risk of Bias Tool and PEDro scale.

RESULTS

Twenty-six RCTs were included in the qualitative analysis and sixteen in the meta-analysis. There were no significant differences in PPTs between tDCS and sham, but differences were observed when applying tDCS over S1 in PPTs compared to sham. Significant differences in CPTs were observed between tDCS and sham over DLPFC and differences in pain intensity were observed between tDCS and sham over M1. Non-significant effects were found for the effects of tDCS on HPTs.

CONCLUSION

tDCS anodic over S1 stimulation increases PPTs, while a-tDCS over DLPFC affects CPTs. The HPTs with tDCS are worse. Finally, M1 a-tDCS seems to reduce evoked pain intensity in healthy subjects.

Clinical Efficacy of 2-Needle Joint Lavage for Osteoarthritis-Related Knee Pain and Predictors of Response Based on Knee MRI Osteoarthritis Knee Score: A Medical Records Review Study

BACKGROUND

Knee osteoarthritis (OA) is notoriously difficult to treat. Pain is the key symptom for patients to seek medical attention. This study aimed to evaluate the therapeutic efficacy of joint lavage (JL) for OA-related knee pain and to explore the knee pathological changes detected by magnetic resonance imaging that may affect the prognosis of patients who received JL.

METHODS

Eighty-two hospitalized patients who were diagnosed with knee OA and received JL in our department were finally enrolled in this study. The patients' clinical data including Numeric Rating Scale (NRS), Western Ontario and McMaster Osteoarthritis Index pain subscale, analgesic medication usage, adverse events, and magnetic resonance imaging data of the affected knee joint scored by the MRI Osteoarthritis Knee Score were recorded and analyzed.

RESULTS

The NRS scores significantly decreased after JL and remained steady until 6 months ( p < 0.001). The Western Ontario and McMaster Osteoarthritis Index pain scores and the percentage of patients who needed analgesic medication significantly decreased at 6 months compared with baseline ( p < 0.001). At 6 months after JL, 51 of the 82 patients experienced ≥50% improvement in their NRS scores (effective). Multivariate binary logistic regression analysis revealed that duration of pain (odds ratio [OR], 1.022; 95% confidence interval [CI], 1.003-1.042; p = 0.024), bone marrow lesion score (OR, 1.221; 95% CI, 1.028-1.450; p = 0.023), and cartilage loss score (OR, 1.272; 95% CI, 1.021-1.585; p = 0.032) significantly influenced the therapeutic efficacy of JL.

CONCLUSIONS

JL treatment can significantly alleviate the OA-related knee pain in at least 6 months. JL tends to provide limited benefit for patients with long duration of pain, serious bone marrow lesions, and severe cartilage loss.

The effects of anodal tDCS on pain reduction in people with knee osteoarthritis: A systematic review and meta-analysis

OBJECTIVES

To synthesise the literature on the efficacy of primary motor cortex anodal transcranial direct current stimulation (M1-a-tDCS), as a standalone or priming technique, for pain reduction in people with knee osteoarthritis (KOA).

METHODS

The systematic literature search was conducted in MEDLINE, CINAHL, Embase and CENTRAL according to PRISMA statement.

RESULTS

Fourteen studies involving 740 people with KOA were included. In the meta-analysis, six studies compared a-tDCS alone with sham stimulation, and five studies compared a-tDCS combined with other methods with sham stimulation. We found positive effect of a-tDCS alone on pain in KOA (standard mean difference (SMD) -0.52; 95% CI, -0.78 to -0.25; P=0.001; I2 = 69%). Further, a-tDCS with other treatments showed positive effect (SMD -1.23; 95% CI, -1.59 to -0.88; P<0.001; I2 = 48%) on pain in people with KOA. This evidence showed low certainty due to a high risk of bias and imprecision.

DISCUSSION AND CONCLUSION

A-tDCS could be considered as standalone and an adjunct treatment for pain reduction in people with KOA. Future randomised studies should address quality issues, including small sample size, to enhance the overall certainty of the findings.

SIGNIFICANCE

A-tDCS can be used as a standalone and adjunct treatment for KOA.

STUDY REGISTRATION

PROSPERO number CRD42021255114.

Functional and Neural Correlates Associated with Conditioned Pain Modulation in Patients with Chronic Knee Osteoarthritis Pain: A Cross-Sectional Study

Background: In this study, we aimed to assess the factors that predict a dysfunctional conditioned pain modulation (CPM) in chronic knee OA. Methods: This is a cross-sectional analysis of patients with chronic knee OA from a prospective cohort study in Brazil (n = 85). We performed linear and logistic multivariate regression models using the purposeful selection approach to test the relationship between the CPM in both knees (average) as a dependent variable and demographics, clinical, and neurophysiological as independent variables. Results: A significant negative association between WOMAC pain scores and CPM (β: -0.13) was found. This association was modified by the subjects' race, being stronger in the non-white subjects. In our logistic regression models, pain intensity indexed with the WOMAC pain scale remained a significant association with dichotomized CPM. Furthermore, a significant CPM association with balance, indexed with the Berg Balance score, was evidenced (β: 0.04). Neurophysiological variables showed a significant negative relationship with CPM, such as the relative power of delta oscillations in the frontal area (β: -3.11) and central area (β: -3.23). There was no significant relationship between CPM and the following domains: cognitive, emotion, sleep, opioid receptor polymorphisms, and intrinsic variables of OA disease. There was no association of CPM with TMS-indexed inhibitory markers. Conclusions: These results may indicate that less function of the pain descending inhibitory system in patients with OA is correlated with higher activity-related pain (WOMAC), less balance, and cortical plasticity especially with increased low-frequency (delta) brain oscillations. These associations seem modified by race.

Association of APOE-ε4, Osteoarthritis, β-Amyloid, and Tau Accumulation in Primary Motor and Somatosensory Regions in Alzheimer Disease

BACKGROUND AND OBJECTIVES

One of the most prevalent chronic diseases, osteoarthritis (OA), may work in conjunction with APOE-ε4 to accelerate Alzheimer disease (AD) alterations, particularly in the primary motor (precentral) and somatosensory (postcentral) cortices. To understand the reasoning behind this, we investigated how OA and APOE-ε4 influence the accumulation of β-amyloid (Aβ) and tau accumulation in primary motor and somatosensory regions in Aβ-positive (Aβ+) older individuals.

METHODS

We selected Aβ+ Alzheimer Disease Neuroimaging Initiative participants, defined by baseline 18F-florbetapir (FBP) Aβ PET standardized uptake value ratio (SUVR) of AD summary cortical regions, who had longitudinal Aβ PET, the records of OA medical history, and APOE-ε4 genotyping. We examined how OA and APOE-ε4 relate to baseline and longitudinal Aβ accumulation and tau deposition measured at follow-up in precentral and postcentral cortical areas and how they modulate Aβ-associated future higher tau levels, adjusting for age, sex, and diagnosis and using multiple comparison corrections.

RESULTS

A total of 374 individuals (mean age 75 years, 49.2% female, 62.8% APOE-ε4 carriers) who underwent longitudinal FBP PET with a median follow-up of 3.3 years (interquartile range [IQR] 3.4, range 1.6-9.4) were analyzed, and 96 people had 18F-flortaucipir (FTP) tau PET measured at a median of 5.4 (IQR 1.9, range 4.0-9.3) years postbaseline FBP PET. Neither OA nor APOE-ε4 was related to baseline FBP SUVR in precentral and postcentral regions. At follow-up, OA rather than APOE-ε4 was associated with faster Aβ accumulation in postcentral region (β = 0.005, 95% CI 0.001-0.008) over time. In addition, OA but not the APOE-ε4 allele was strongly linked to higher follow-up FTP tau levels in precentral (β = 0.098, 95% CI 0.034-0.162) and postcentral (β = 0.105, 95% CI 0.040-0.169) cortices. OA and APOE-ε4 were also interactively associated with higher follow-up FTP tau deposition in precentral (β = 0.128, 95% CI 0.030-0.226) and postcentral (β = 0.124, 95% CI 0.027-0.223) regions.

DISCUSSION

This study suggests that OA was associated with faster Aβ accumulation and higher Aβ-dependent future tau deposition in primary motor and somatosensory regions, providing novel insights into how OA increases the risk of AD.

Drosophila pain sensitization and modulation unveiled by a novel pain model and analgesic drugs

In mammals, pain is regulated by the combination of an ascending stimulating and descending inhibitory pain pathway. It remains an intriguing question whether such pain pathways are of ancient origin and conserved in invertebrates. Here we report a new Drosophila pain model and use it to elucidate the pain pathways present in flies. The model employs transgenic flies expressing the human capsaicin receptor TRPV1 in sensory nociceptor neurons, which innervate the whole fly body, including the mouth. Upon capsaicin sipping, the flies abruptly displayed pain-related behaviors such as running away, scurrying around, rubbing vigorously, and pulling at their mouth parts, suggesting that capsaicin stimulated nociceptors in the mouth via activating TRPV1. When reared on capsaicin-containing food, the animals died of starvation, demonstrating the degree of pain experienced. This death rate was reduced by treatment both with NSAIDs and gabapentin, analgesics that inhibit the sensitized ascending pain pathway, and with antidepressants, GABAergic agonists, and morphine, analgesics that strengthen the descending inhibitory pathway. Our results suggest Drosophila to possess intricate pain sensitization and modulation mechanisms similar to mammals, and we propose that this simple, non-invasive feeding assay has utility for high-throughput evaluation and screening of analgesic compounds.

Transcranial direct current stimulation combined with peripheral stimulation in chronic pain: a systematic review and meta-analysis

INTRODUCTION

The combination of Transcranial Direct Current Stimulation (tDCS) with peripheral stimulation may optimize their effects and bring positive results in treatment of people with chronic pain.

AREAS COVERED

A systematic review with meta-analysis of randomized and non-randomized trials was performed to investigate the combination of tDCS with peripheral stimulation in adults with chronic pain. The primary outcome was pain intensity. Six studies were included in this review (sample of 228 participants), which investigated the combination of tDCS and transcutaneous electrical nerve stimulation, peripheral electrical stimulation, breathing-controlled electrical stimulation and intramuscular electrical stimulation. The conditions studied were knee osteoarthritis, spinal cord injury, chronic low back pain, and neurogenic pain of the arms. Pain intensity, measured by visual analog scale or numerical rating scale, was reduced in all included studies when at least one of the interventions was active, regardless they were combined or alone, with or without tDCS. However, meta-analysis showed superiority of tDCS used in combination with peripheral stimulation.

EXPERT OPINION

This systematic review and meta-analysis suggests positive effects of tDCS combined with peripheral stimulation in chronic pain conditions. However, the evidence of the primary outcome was classified as low quality due to the limited number of studies.

Feasibility, Acceptability, and Efficacy of Home-Based Transcranial Direct Current Stimulation on Pain in Older Adults with Alzheimer's Disease and Related Dementias: A Randomized Sham-Controlled Pilot Clinical Trial

Although transcranial direct current stimulation (tDCS) is emerging as a convenient pain relief modality for several chronic pain conditions, its feasibility, acceptability, and preliminary efficacy on pain in patients with Alzheimer's disease and related dementias (ADRD) have not been investigated. The purpose of this pilot study was to assess the feasibility, acceptability, and preliminary efficacy of 5, 20-min home-based tDCS sessions on chronic pain in older adults with ADRD. We randomly assigned 40 participants to active (n = 20) or sham (n = 20) tDCS. Clinical pain intensity was assessed using a numeric rating scale (NRS) with patients and a proxy measure (MOBID-2) with caregivers. We observed significant reductions of pain intensity for patients in the active tDCS group as reflected by both pain measures (NRS: Cohen's d = 0.69, p-value = 0.02); MOBID-2: Cohen's d = 1.12, p-value = 0.001). Moreover, we found home-based tDCS was feasible and acceptable intervention approach for pain in ADRD. These findings suggest the need for large-scale randomized controlled studies with larger samples and extended versions of tDCS to relieve chronic pain on the long-term for individuals with ADRD.

Development of a Clinical Prediction Rule for Treatment Success with Transcranial Direct Current Stimulation for Knee Osteoarthritis Pain: A Secondary Analysis of a Double-Blind Randomized Controlled Trial

The study’s objective was to develop a clinical prediction rule that predicts a clinically significant analgesic effect on chronic knee osteoarthritis pain after transcranial direct current stimulation treatment. This is a secondary analysis from a double-blind randomized controlled trial. Data from 51 individuals with chronic knee osteoarthritis pain and an impaired descending pain inhibitory system were used. The intervention comprised a 15-session protocol of anodal primary motor cortex transcranial direct current stimulation. Treatment success was defined by the Western Ontario and McMaster Universities’ Osteoarthritis Index pain subscale. Accuracy statistics were calculated for each potential predictor and for the final model. The final logistic regression model was statistically significant (p < 0.01) and comprised five physical and psychosocial predictor variables that together yielded a positive likelihood ratio of 14.40 (95% CI: 3.66−56.69) and an 85% (95%CI: 60−96%) post-test probability of success. This is the first clinical prediction rule proposed for transcranial direct current stimulation in patients with chronic pain. The model underscores the importance of both physical and psychosocial factors as predictors of the analgesic response to transcranial direct current stimulation treatment. Validation of the proposed clinical prediction rule should be performed in other datasets.

Non-invasive brain stimulation for osteoarthritis

Osteoarthritis (OA) is a degenerative joint disease, the prevalence of OA is increasing, and the elderly are the most common in patients with OA. OA has a severe impact on the daily life of patients, this increases the demand for treatment of OA. In recent years, the application of non-invasive brain stimulation (NIBS) has attracted extensive attention. It has been confirmed that NIBS plays an important role in regulating cortical excitability and oscillatory rhythm in specific brain regions. In this review, we summarized the therapeutic effects and mechanisms of different NIBS techniques in OA, clarified the potential of NIBS as a treatment choice for OA, and provided prospects for further research in the future.

Efficacy of Home-Based Transcranial Direct Current Stimulation on Experimental Pain Sensitivity in Older Adults with Knee Osteoarthritis: A Randomized, Sham-Controlled Clinical Trial

Although transcranial direct current stimulation (tDCS) is encouraging regarding clinical pain intensity for individuals with knee osteoarthritis, very few studies have explored its impact on experimental pain sensitivity, which may hinder our understanding of underlying therapeutic mechanisms. The purpose of this study was to assess the efficacy of 15 home-based tDCS sessions on experimental pain sensitivity and explore its relationships with clinical pain intensity. We randomly assigned 120 participants to active tDCS (n = 60) and sham tDCS (n = 60). Quantitative sensory testing (QST) was used, including heat pain threshold and tolerance, pressure pain threshold, and conditioned pain modulation. Patients in the active tDCS group exhibited reduced experimental pain sensitivity as reflected by all QST measures at the end of treatment. Furthermore, correlations were observed between changes in clinical pain intensity and experimental pain sensitivity. These findings warrant further studies on tDCS and experimental pain sensitivity in patients with knee osteoarthritis and exploring the magnitude and sustainability of effects on a longer term.

Transcranial Direct Current Stimulation (tDCS): Pain Management in End-Stage Renal Disease - Report of an Early Randomized Controlled Trial

CONTEXT

Chronic pain in end-stage renal disease (ESRD) is an increasingly neglected clinical problem affecting more than 60% of patients. Long-term chronic pain could be associated with brain imbalance in circuits of pain matrix and is associated with poor quality of life (QoL) and mood disturbance.

OBJECTIVES

The aim of this study was evaluating the effects of transcranial direct current stimulation (tDCS) on pain, QoL, depression, anxiety and affectivity in ESRD patients undergoing hemodialysis (HD).

METHODS

This double-blind, randomized, sham-controlled trial included 30 patients with chronic pain undergoing HD. Participants were allocated to Active tDCS and Sham tDCS and received ten non-consecutive sessions of anodal motor cortex stimulation (M1/Sp2 montage) at 2 mA intensity for 20 min. The primary outcome was pain assessed using numeric rating scale (NRS) and collected at baseline, immediately after the 10th day of intervention, one week, two weeks, and four weeks after the last stimulation. Secondary outcomes included QoL, depression, anxiety and affectivity collected before and after intervention.

RESULTS

A mixed ANOVA model showed significant interaction between group and time on pain F(4.112) = 3.106, P = 0.01 with main effects of group (P = 0.03). Before and after intervention, a significant improvement was observed in QoL (P = 0.009), general health (P = 0.03), fatigue (P = 0.05), symptoms (P = 0.05) depression (P = 0.01) and anxiety (P = 0.01). No difference was found for affectivity.

CONCLUSION

Anodal tDCS over the motor cortex emerges as a potential therapeutic approach for improving pain, QoL, and mood in patients with ESRD.

Self-administered transcranial direct current stimulation for pain in older adults with knee osteoarthritis: A randomized controlled study

BACKGROUND

Knee osteoarthritis (OA) is a leading cause of pain in older adults. Previous studies indicated clinic-based transcranial direct current stimulation (tDCS) was effective to reduce pain in various populations, but no published studies have reported the efficacy of home-based self-administered tDCS in older adults with knee OA using a randomized clinical study.

OBJECTIVE

The purpose of this study was to evaluate the efficacy and feasibility of tDCS on clinical pain intensity in adults with knee OA pain.

METHODS

One hundred twenty participants aged 50-85 years with knee OA pain were randomly assigned to receive fifteen daily sessions of 2 mA tDCS for 20 min (n = 60) or sham tDCS (n = 60) over 3 weeks with remote supervision via telehealth. Clinical pain intensity was measured by the Numeric Rating Scale and Western Ontario and McMaster Universities Osteoarthritis Index. Also, we collected data on the tDCS experience via a questionnaire.

RESULTS

Participants (68% female) had a mean age of 66 years. Active tDCS significantly reduced pain intensity compared to sham tDCS after completion of the fifteen daily sessions (Cohen's d = 1.20; p-value < 0.0001). Participants showed high levels of satisfaction with their tDCS experience, and there have been no adverse events.

CONCLUSION

We demonstrated that home-based self-administered tDCS was feasible and reduced clinical pain intensity in older adults with knee OA, which can increase its accessibility. Future studies with multi-site randomized controlled trials are needed to validate our findings.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04016272.

Relieving Chronic Musculoskeletal Pain in Older Adults Using Transcranial Direct Current Stimulation: Effects on Pain Intensity, Quality, and Pain-Related Outcomes

Introduction

Chronic pain is a significant health problem and is particularly prevalent amongst the elderly. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has been proposed to reduce chronic pain. The aim of this study was to evaluate and compare the efficacy of active and sham tDCS in reducing pain in older individuals living with chronic musculoskeletal pain.

Materials and Methods

Twenty-four older individuals (mean age: 68 ± 7 years) suffering from chronic musculoskeletal pain were randomized to receive either anodal tDCS over the contralateral motor cortex (2 mA, 20 min; n = 12) or sham tDCS (20 min; n = 12) for five consecutive days. Pain logbooks were used to measure pain intensity. Questionnaires (McGill Pain Questionnaire, Brief Pain Inventory, Beck Depression Inventory [BDI], Beck Anxiety Inventory, Pain Catastrophizing Scale [PCS], and Margolis Pain Drawing and Scoring System [MPDSS]) were also used to assess pain in its globality.

Results

Analysis of pain logbooks revealed that active tDCS led to a reduction in daily average pain intensity (all p ≤ 0.04), while sham tDCS did not produce any change (p = 0.15). Between-group comparisons for change in pain intensity reduction between active and sham tDCS showed a trend during treatment (p = 0.08) which was significant at the follow-up period (p = 0.02). Active tDCS also improved scores of all questionnaires (all p ≤ 0.02), while sham tDCS only reduced MPDSS scores (p = 0.04). Between-group comparisons for the pain-related outcomes showed significant differences for BDI et PCS after the last tDCS session.

Conclusions

These results suggest that anodal tDCS applied over the primary motor cortex is an effective modality to decrease pain in older individuals. tDCS can also improve other key outcomes, such as physical and emotional functioning, and catastrophic thinking.

Scientific Knowledge Graph and Trend Analysis of Central Sensitization: A Bibliometric Analysis

BACKGROUND

Central sensitization refers to a state of hypersensitivity in the central nervous system and is associated with the development and maintenance of chronic pain. Central sensitization plays an essential role in various diseases. Nevertheless, there has been no bibliometric analysis before in this field. The purpose of this study was to provide critical themes and trends in the area of central sensitization, to build a network of knowledge, and to facilitate the future development of relevant basic and clinical research.

METHODS

Publications on central sensitization were extracted from the Science Citation Index-Expanded. We used R software to systematically analyze the countries, institutions, authors, journals, references, and keywords of the publications. Besides, conceptual structure, intellectual structure, and social structure were constructed.

RESULTS

A total of 4466 publications were included. Research in the field of central sensitization generally showed a steady upward trend. The three structural networks showed that the United States is the leading country in this field. Arendt-Nielsen L and Woolf CJ were the most productive and influential authors, respectively. "Pain" was the journal with the most studies. Most journals that published and cited articles about central sensitization were academically influential. Cluster analysis revealed that research in central sensitization contains three main conceptual clusters, and the themes of research evolve frequently. Current research focuses on the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

CONCLUSION

Central sensitization received widespread attention. The United States led the way in academic activity. In this field, the current situation of cooperation and communication between different countries and institutions is positive. The present research hotspots were the pathogenesis of central sensitization in neuropathic pain, the role of central sensitization in different diseases, and related clinical double-blind trials.

The effect of high-definition transcranial direct current stimulation on pain processing in a healthy population: A single-blinded crossover controlled study

Transcranial direct current stimulation (tDCS) is increasingly used in pain treatment. tDCS targeting both primary motor cortex (M1) and dorsolateral prefrontal cortex (DLPFC) may modulate the descending pain inhibitory system, however, it remains controversial regarding the optimal stimulation region for pain modulation. Therefore, this study aimed to explore the effects of high-definition anodic stimulation of M1 and DLPFC on conditioned pain modulation (CPM) and pain thresholds and establish a preferred stimulation setting. Twenty-six healthy adults were randomly assigned to M1-tDCS, DLPFC-tDCS, or sham-tDCS groups. During the three sessions, each participant received an active or sham stimulation of 2 mA for 20 min, with at least 3 days' interval between sessions. Quantitative sensory tests were performed to obtain pressure pain threshold (PPT), cold pain threshold (CPT), and CPM before and after the tDCS intervention. Only M1-tDCS significantly increased CPM in healthy individuals compared with sham control (P = 0.004). No statistically significant difference was found in PPT and CPT between tDCS vs. sham control (P > 0.05). Our findings further support the important role of M1 as a target in pain regulation. Further large-scale, multicenter studies in chronic pain populations are needed to validate the alterations of distinct target brain regions related to pain and thus for an optimal target stimulation strategy in pain management.