Mechanisms of transcranial direct current stimulation (tDCS) for pain in patients with fibromyalgia syndrome.

Fibromyalgia syndrome (FMS) is a recurrent pain condition that can be challenging to treat. Transcranial direct current stimulation (tDCS) has become a promising non-invasive therapeutic option in alleviating FMS pain, but the mechanisms underlying its effectiveness are not yet fully understood. In this article, we discuss the most current research investigating the analgesic effects of tDCS on FMS and discuss the potential mechanisms. TDCS may exert its analgesic effects by influencing neuronal activity in the brain, altering cortical excitability, changing regional cerebral blood flow, modulating neurotransmission and neuroinflammation, and inducing neuroplasticity. Overall, evidence points to tDCS as a potentially safe and efficient pain relief choice for FMS by multiple underlying mechanisms. This article provides a thorough overview of our ongoing knowledge regarding the mechanisms underlying tDCS and emphasizes the possibility of further studies to improve the clinical utility of tDCS as a pain management tool.

Reliability and Validity of the Star Excursion Balance Test for Evaluating Dynamic Balance of Upper Extremities.

BACKGROUND: Upper extremity (UE) dynamic balance is a significant physical fitness ability, which includes high-level neuromuscular proprioception, joint mobility, force, and coordination. The evaluation methods of UE dynamic balance are insufficient and lack experimental support. The Star Excursion Balance Test (SEBT) is a reliable assessment of dynamic balance and injury risk of the lower extremity. HYPOTHESIS: The UE-SEBT is a reliable and reproducible approach for evaluating dynamic balance of UEs. STUDY DESIGN: Observational study. LEVEL OF EVIDENCE: Level 4. METHODS: This cross-sectional study recruited 65 healthy adults. All participants were required to complete UE-SEBT, UE Y-balance test (UE-YBT), maximal voluntary isometric contraction (MVIC) of UE, closed kinetic chain UE stability test (CKCUEST), trunk flexor endurance test (TFET), trunk extensor endurance test (TEET), and lateral trunk endurance test (LTET). Intra- and inter-rater reliability and the correlation of UE-SEBT with other outcomes were measured. RESULTS: Among the participants, the intra- and interoperator reliability of UE-SEBT in all directions and composite score achieved a moderate-to-excellent (intraclass correlation coefficients [ICC], 0.729-0.946) reliability. For validity, the UE-SEBT had a moderate to very strong correlation with UE-YBT (r = 0.315-0.755, P < 0.01) and a strong correlation with CKCUEST (r = 0.4-0.67, P < 0.01). Furthermore, the UE-SEBT performance showed weak-to-strong correlations with MVIC (r = 0.26-0.43, P < 0.05). UE-SEBT was also correlated with LTET, TEET, and TFET to varying degrees. CONCLUSION: UE-SEBT has good reliability and validity to assess UE dynamic balance compared with other tests. CLINICAL RELEVANCE: UE-SEBT can be used as a clinical assessment method to evaluate UE dynamic balance and injury prevention.

Association between smoking and incident back pain: A prospective cohort study with 438 510 participants.

Background: Although smoking is a known potential contributor to back pain, there is still a lack of quantitative studies on the effects of different doses on back pain (BP) occurrence, including a lack of a longitudinal cohorts. To address this gap, we aimed to investigate the association between various smoking-related exposures and back pain incidence to advance global efforts toward smoking cessation and guide primary prevention of BP. Methods: In this prospective cohort study, we retrieved data on 438 510 patients from the UK Biobank who were free of back pain and who were recruited in 2006-2010, and followed them up from baseline through 1 April 2022. We extracted data on smoking-related exposures, including smoking status (SS), number of cigarettes smoked daily (CPD), and pack-years of own smoking (PY) and examined back pain incidence as an outcome. We used a Cox proportional hazard model adjusted for several covariates, multiple imputation methods, and population attribution fraction. Results: During the median follow-up of 12.98 years, 31 467 participants developed BP, with incidence rates in former and current smokers of 1.13 (95% confidence interval (CI) = 1.10-1.16, P < 0.000) and 1.50 (95% CI = 1.45-1.56, P < 0.000), respectively. The hazard ratios (HRs) of participants who smoked more than 30 CPD and those with more than 30 PY were 1.45 (95% CI = 1.36-1.55, P < 0.000) and 1.45 (95% CI = 1.40-1.50, P < 0.000), respectively. Relative to male, female smokers were at more risk of developing BP. Not smoking, quitting smoking, and reducing CPD and PY could lower the BP risk by 7.8%, 5.4%, 9.8%, and 18.0%, respectively. Conclusions: Ever smoking, higher cigarette consumption daily, and increased smoking intensity were associated with an increased BP risk. This association was stronger in female smokers. Not smoking, smoking cessation, and reducing smoking volume and intensity were effective measures to prevent BP occurrence.

Spinal posture assessment and low back pain.

Postural assessment can help doctors and therapists identify risk factors for low back pain and determine appropriate follow-up treatment. Postural alignment is not perfectly symmetrical, and small asymmetries can instead represent norms and criteria for postural evaluation. It is necessary to comprehensively observe patients' posture in all directions and analyze the factors related to posture evaluation. The results of reliability show that in general intra-rater reliability is higher than inter-rater reliability, and inclinometers are being more reliable than other instrumentations. Some common postural problems can cause lumbar discomfort, and prolonged poor posture is a potential risk factor for lumbar spine injuries. On the basis of previous studies on posture evaluation, a unified standardized method for posture evaluation must be established in future research.

Association Between Smoking and Pain, Functional Disability, Anxiety and Depression in Patients With Chronic Low Back Pain.

Objectives: Chronic low back pain (CLBP) accounts for a majority of the disability associated with LBP, which can produce long-term negative effects. This cross-sectional study aimed to investigate the association between smoking and pain, dysfunction and psychological status in patients with CLBP. Methods: The 54 patients with CLBP were recruited and divided into smoking and non-smoking groups. Their pain, dysfunction, anxiety, depression, fear and quality of life were evaluated. The amount of cigarettes smoked daily was recorded. Results: Significant differences in VAS, ODI, RMDQ and FABQ and the impact of LBP on life and work were found between smoking and non-smoking patients. In addition, a correlation was found between the daily cigarette smoking amount and VASmax, FABQtotal, SDS and FABQ-W. Moreover, a correlation was observed between the amount of cigarettes smoked daily and the degree of impact of low back pain on work. Conclusion: The study found that smoking affected the aggravation of symptoms in patients with CLBP, which indicated that patients with CLBP and people at risk of LBP should be aware of the harm caused by smoking.

Effects of High-Definition Transcranial Direct Current Stimulation Targeting the Anterior Cingulate Cortex on the Pain Thresholds: A Randomized Controlled Trial.

BACKGROUND: The majority of existing clinical studies used active transcranial direct current stimulation (tDCS) over superficial areas of the pain neuromatrix to regulate pain, with conflicting results. Few studies have investigated the effect of tDCS on pain thresholds by focusing on targets in deep parts of the pain neuromatrix. METHODS: This study applied a single session of high-definition tDCS (HD-tDCS) targeting the anterior cingulate cortex (ACC) and used a parallel and sham-controlled design to compare the antinociceptive effects in healthy individuals by assessing changes in pain thresholds. Sixty-six female individuals (mean age, 20.5 ± 2.4 years) were randomly allocated into the anodal, cathodal, or sham HD-tDCS groups. The primary outcome of the study was pain thresholds (pressure pain threshold, heat pain threshold, and cold pain threshold), which were evaluated before and after stimulation through the use of quantitative sensory tests. RESULTS: Only cathodal HD-tDCS targeting the ACC significantly increased heat pain threshold (P < 0.05) and pressure pain threshold (P < 0.01) in healthy individuals compared with sham stimulation. Neither anodal nor cathodal HD-tDCS showed significant analgesic effects on cold pain threshold. Furthermore, no statistically significant difference was found in pain thresholds between anodal and sham HD-tDCS (P > 0.38). Independent of HD-tDCS protocols, the positive and negative affective schedule scores were decreased immediately after stimulation compared with baseline. CONCLUSIONS: The present study has found that cathodal HD-tDCS targeting the ACC provided a strong antinociceptive effect (increase in pain threshold), demonstrating a positive biological effect of HD-tDCS.

Non-invasive brain neuromodulation techniques for chronic low back pain.

Structural and functional changes of the brain occur in many chronic pain conditions, including chronic low back pain (CLBP), and these brain abnormalities can be reversed by effective treatment. Research on the clinical applications of non-invasive brain neuromodulation (NIBS) techniques for chronic pain is increasing. Unfortunately, little is known about the effectiveness of NIBS on CLBP, which limits its application in clinical pain management. Therefore, we summarized the effectiveness and limitations of NIBS techniques on CLBP management and described the effects and mechanisms of NIBS approaches on CLBP in this review. Overall, NIBS may be effective for the treatment of CLBP. And the analgesic mechanisms of NIBS for CLBP may involve the regulation of pain signal pathway, synaptic plasticity, neuroprotective effect, neuroinflammation modulation, and variations in cerebral blood flow and metabolism. Current NIBS studies for CLBP have limitations, such as small sample size, relative low quality of evidence, and lack of mechanistic studies. Further studies on the effect of NIBS are needed, especially randomized controlled trials with high quality and large sample size.

The effect and mechanism of traditional Chinese exercise for chronic low back pain in middle-aged and elderly patients: A systematic review.

Background: Increasing lines of evidence indicate that traditional Chinese exercise (TCE) has potential benefits in improving chronic low back pain (CLBP) symptoms. To assess the clinical efficacy of TCE in the treatment of CLBP, we performed a systematic review of existing randomized controlled trials (RCTs) of CLBP and summarized the neural mechanisms underlying TCE in the treatment of CLBP. Methods: A systematic search was conducted in four electronic databases: PubMed, Embase, the Cochrane Library, and EBSCO from January 1991 to March 2022. The quality of all included RCTs was evaluated by the Physiotherapy Evidence Database Scale (PEDro). The primary outcomes included pain severity and pain-related disability. Results: A total of 11 RCTs with 1,256 middle-aged and elderly patients with CLBP were included. The quality of all 11 included RCTs ranged from moderate to high according to PEDro. Results suggested that TCE could considerably reduce pain intensity in patients with CLBP. Overall, most studies did not find any difference in secondary outcomes (quality of life, depression, and sleep quality). Conclusion: The neurophysiological mechanism of TCE for treating CLBP could be linked to meditation and breathing, posture control, strength and flexibility training, and regulation of pain-related brain networks. Our systematic review showed that TCE appears to be effective in alleviating pain in patients with CLBP.

Effect of exercise intervention on social distance in middle-aged and elderly patients with chronic low back pain.

Background: Increased social distance is one of the manifestations of social impairment. Chronic low back pain (CLBP) is one of factors associated with increased social distance and social withdrawal. Exercise therapy is an effective means to social impairment. However, whether exercise could reduce social distance in patients with CLBP remains unknown. This study aimed to investigate the effect of exercise on social distance in middle-aged and elderly patients with CLBP. Methods: The longitudinal intervention recruited 29 middle-aged and elderly patients with CLBP from various communities in Yangpu District, Shanghai, China. The participants received exercise intervention for 8 weeks. The assessments were conducted before and after the intervention, including social distance, pain intensity, unpleasantness of pain, Roland-Morris Questionnaire (RMDQ), Self-Rating Anxiety Scale (SAS), and Self-Rating Depression Scale (SDS). Intention to treat analysis was performed. Results: After the 8-week exercise intervention, the social distance of patients with CLBP was shorter than that before intervention and showed significant difference (p < 0.05). The scores of pain intensity, unpleasantness of pain, RMDQ, SAS, and SDS also decreased and were significantly different between pre- and post-intervention (p < 0.05). In addition, the social distance, pain intensity, unpleasantness of pain, RMDQ, SAS, and SDS scores of the moderate CLBP group decreased more after the intervention compared with those of the mild CLBP group. Conclusion: The 8-week exercise intervention cannot only shorten the social distance in middle-aged and elderly patients with CLBP but also relieve pain, disability, and negative emotions.

Non-invasive Brain Stimulation for Central Neuropathic Pain.

The research and clinical application of the noninvasive brain stimulation (NIBS) technique in the treatment of neuropathic pain (NP) are increasing. In this review article, we outline the effectiveness and limitations of the NIBS approach in treating common central neuropathic pain (CNP). This article summarizes the research progress of NIBS in the treatment of different CNPs and describes the effects and mechanisms of these methods on different CNPs. Repetitive transcranial magnetic stimulation (rTMS) analgesic research has been relatively mature and applied to a variety of CNP treatments. But the optimal stimulation targets, stimulation intensity, and stimulation time of transcranial direct current stimulation (tDCS) for each type of CNP are still difficult to identify. The analgesic mechanism of rTMS is similar to that of tDCS, both of which change cortical excitability and synaptic plasticity, regulate the release of related neurotransmitters and affect the structural and functional connections of brain regions associated with pain processing and regulation. Some deficiencies are found in current NIBS relevant studies, such as small sample size, difficulty to avoid placebo effect, and insufficient research on analgesia mechanism. Future research should gradually carry out large-scale, multicenter studies to test the stability and reliability of the analgesic effects of NIBS.

Research Hotspots and Trends of Exercise on Parkinson's Disease: A Global Bibliometric Analysis From 2012 to 2021.

Background: Parkinson's disease is a chronic neurodegenerative disease, which can be alleviated in drug treatment, but with evident side effects. At the same time, increasing evidence shows that exercise can significantly improve the symptoms of patients with Parkinson's disease, with an effect that cannot be achieved by drug treatment. The related research on exercise on Parkinson's disease increases rapidly with the passage of time. However, the research analysis on Parkinson's disease by means of bibliometrics is rare. The purpose of this study is to perform a bibliometric analysis of the research hotspots and development trends of the global movement on Parkinson's disease from 2012 to 2021. Methods: The literature was derived from the Web of Science core collection database, and the social science citation index was set as SCI-EXPANDED. The language was set to English, and the literature category was set as article and review and published from 2012 to 2021. CiteSpace and other software were used to analyze the relationship among published documents, countries, institutions, journals, authors, references, disciplines, and keywords. Results: A total of 2,222 articles were included in the analysis. The analysis showed that the publication volume increased with the increase in years, with a total of 76 countries and 546 academic journals published; the largest number was that of the United States. The journals are mainly concentrated in the fields of neurology, sports, and ophthalmology. Rush University and Movement Disorders journals are the main institutions and journals. The cited keywords show that trial, cognition, and interference are the research hotspots and development trends in recent years. Conclusion: The number of published articles on Parkinson's disease by exercise has increased rapidly in the past 10 years, and the bibliometric analysis can provide useful information for future research teams and researchers.

The Last Decade Publications on Diabetic Peripheral Neuropathic Pain: A Bibliometric Analysis.

Background: Diabetic peripheral neuropathic pain (DPNP) is a usual complication of diabetes with a high incidence and mortality. Many diabetes-related studies have been published in various journals. However, bibliometrics and visual analyses in the domain of DPNP research are still lacking. The study aimed to offer a visual method to observe the systematic overview of global research in this field from 2011 to 2021. Methods: The publications from the Science Citation Index Expanded in Web of Science (WOS) in the past 11 years (from 2011 to 2021) were collected and sorted out, and those related to DPNP were extracted and analyzed. The article language was limited in English. Then, CiteSpace V was used for the bibliometric analysis of the extracted literature. Results: A total of 1,422 articles met the inclusion criteria. A continuous but unstable growth in the amounts of papers published on DPNP was observed over the last 11 years. The subject sort of the 1,422 papers mainly concentrates on Endocrinology Metabolism, Clinical neurology and Neurosciences from the WOS. According to the research contribution in the field of DPNP, the United States occupies a leading position, with the highest amounts of publications, citations, open access, and the H- index. Conclusion: This study provides a visual analysis method for the trend of DPNP, and offers some hidden serviceable information that may define new directions for future research.