Frequency and features of the central poststroke pain

Prevalence, Trajectory, and Factors Associated With Patient-Reported Nonmotor Outcomes After Stroke: A Systematic Review and Meta-Analysis

Importance

The evidence on nonmotor outcomes after acute ischemic stroke and intracerebral hemorrhage (ICH) is limited and domain-specific. The prevalence, natural history, and factors associated with nonmotor outcomes across multiple domains are unclear.

Objective

To synthesize the published data and to identify the prevalence, natural history, and factors associated with multidomain nonmotor outcome burden in patients with stroke.

Data Sources

A search of PubMed, MEDLINE, EMBASE, and PsycINFO databases between January 1999 to June 2023 was supplemented by search of bibliographies of the key articles.

Study Selection

The analysis included prospective cohort studies that reported nonmotor outcomes across 10 domains: anxiety, depression, fatigue, sleep disturbance, social participation, pain, bladder dysfunction, bowel dysfunction (constipation and fecal incontinence), and sexual dysfunction assessed by patient-reported scales.

Data Extraction and Synthesis

Two reviewers independently assessed studies, extracting baseline data, nonmotor prevalence, and follow-up information. Pooled prevalence of nonmotor outcomes was estimated using random-effects models. Meta-regression models were used to analyze natural history and factors associated with nonmotor outcomes. Subgroup analysis was used to assess prevalence by symptom description within each nonmotor domain. Publication bias and study quality were assessed using funnel plots and the Newcastle-Ottawa scale.

Results

A total of 279 prospective cohort studies met the inclusion criteria (117 440 participants with stroke; median [IQR] age, 65 [59-70] years; 209 of 279 studies with more male than female participants) with a nonmotor outcome follow-up period ranging from 30 days to 10 years after stroke. The most prevalent adverse nonmotor outcomes by pooled prevalence were sleep disturbance (59.9%; 95% CI, 53.9%-63.9%), sexual dysfunction (59.8%; 95% CI, 50.0%-69.5%), constipation (58.2%; 95% CI, 53.9%-62.6%), reduced social participation (56.5%; 95% CI, 52.1%-60.8%), bladder dysfunction (45.9%; 95% CI, 38.0%-53.8%), and fatigue (45.2%; 95% CI, 40.7%-49.5%). Meta-regression analysis showed no significant improvement over time for most nonmotor outcomes, except pain (coefficient = -11.0%; P = .05) and sexual dysfunction (coefficient = -24.1%; P < .001). The heterogeneity ranged between 52% and 98% across all studies. The common factors associated with adverse nonmotor outcomes were female sex, studies with mixed stroke cohort (ischemic stroke or ICH), and older age.

Conclusions and Relevance

Patient-reported nonmotor outcomes were common after stroke. Sexual dysfunction, sleep disturbance, constipation, reduced social participation, bladder dysfunction, and fatigue were most prevalent. These adverse outcomes often persisted over time, especially in women, older adults, and those in studies with mixed stroke cohorts.

Central post-stroke pain: advances in clinical and preclinical research

Central poststroke pain (CPSP) is a medical complication that arises poststroke and significantly impacts the quality of life and social functioning of affected individuals. Despite ongoing research, the exact pathomechanisms of CPSP remain unclear, and practical treatments are still unavailable. Our review aims to systematically analyse current clinical and preclinical studies on CPSP, which is critical for identifying gaps in knowledge and guiding the development of effective therapies. The review will clarify the clinical characteristics, evaluation scales and contemporary therapeutic approaches for CPSP based on clinical investigations. It will particularly emphasise the CPSP model initiated by stroke, shedding light on its underlying mechanisms and evaluating treatments validated in preclinical studies. Furthermore, the review will not only highlight methodological limitations in animal trials but also offer specific recommendations to researchers to improve the quality of future investigations and guide the development of effective therapies. This review is expected to provide valuable insights into the current knowledge regarding CPSP and can serve as a guide for future research and clinical practice. The review will contribute to the scientific understanding of CPSP and help develop effective clinical interventions.

Role of Brain Derived Neurotrophic Factor and Related Therapeutic Strategies in Central Post-Stroke Pain

Brain-derived neurotrophic factor (BDNF) is vital for synaptic plasticity, cell persistence, and neuronal development in peripheral and central nervous systems (CNS). Numerous intracellular signalling pathways involving BDNF are well recognized to affect neurogenesis, synaptic function, cell viability, and cognitive function, which in turn affects pathological and physiological aspects of neurons. Stroke has a significant psycho-socioeconomic impact globally. Central post-stroke pain (CPSP), also known as a type of chronic neuropathic pain, is caused by injury to the CNS following a stroke, specifically damage to the somatosensory system. BDNF regulates a broad range of functions directly or via its biologically active isoforms, regulating multiple signalling pathways through interactions with different types of receptors. BDNF has been shown to play a major role in facilitating neuroplasticity during post-stroke recovery and a pro-nociceptive role in pain development in the nervous system. BDNF-tyrosine kinase receptors B (TrkB) pathway promotes neurite outgrowth, neurogenesis, and the prevention of apoptosis, which helps in stroke recovery. Meanwhile, BDNF overexpression plays a role in CPSP via the activation of purinergic receptors P2X4R and P2X7R. The neuronal hyperexcitability that causes CPSP is linked with BDNF-TrkB interactions, changes in ion channels and inflammatory reactions. This review provides an overview of BDNF synthesis, interactions with certain receptors, and potential functions in regulating signalling pathways associated with stroke and CPSP. The pathophysiological mechanisms underlying CPSP, the role of BDNF in CPSP, and the challenges and current treatment strategies targeting BDNF are also discussed.

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

Background

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

Methods

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

Results

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

Conclusion

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

Systematic review registration

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

Non-invasive brain stimulation improves pain in patients with central post-stroke pain: a systematic review and meta-analysis

BACKGROUND

Central post-stroke pain (CPSP) significantly interferes with the quality of life and psychological well-being of stroke patients. Non-invasive brain stimulation (NIBS) has attracted significant attention as an emerging method for treating patients with CPSP.

OBJECTIVE

To compare the clinical efficacy of noninvasive brain stimulation on pain, and psychological status of patients with central post-stroke pain using meta-analysis.

METHODS

A computerized search of multiple databases was performed for identification of randomized controlled trials involving NIBS-led treatment of CPSP patients. Two researchers worked independently on literature screening, data extraction, and quality assessment. Research was conducted from inception of the database until October 2023. RevMan 5.0 and Stata 15.0 software were used to conduct statistical analysis.

RESULTS

Sixteen papers with 807 patients were finally included. The results showed that NIBS reduced patients' pain intensity [SMD = -0.39, 95% CI (-0.54, -0.24), p < 0.01] and was more effective in short-term CPSP patients. However, the included studies did not show a significant impact on psychological status, particularly depression. Subgroup analysis suggested that the M1 stimulation point was more effective than other stimulation points [SMD = -0.45, 95% CI (-0.65, -0.25), p < 0.001]. Other stimulation modalities also demonstrated favorable outcomes when compared to rTMS [SMD = -0.67, 95% CI (-1.09, -0.25), p < 0.01].

CONCLUSION

NIBS has a positive impact on pain relief in patients with CPSP, but does not enhance patients' psychological well-being in terms of anxiety or depression. Furthermore, large-sample, high-quality, and multi-center RCTs are needed to explore the benefits of different stimulation durations and parameters in patients with CPSP. The current study has been registered with Prospero under the registration number CRD42023468419.

Stroke-Induced Central Pain: Overview of the Mechanisms, Management, and Emerging Targets of Central Post-Stroke Pain

The incidence of stroke plays the foremost role in the genesis of central neuropathic pain. Central post-stroke pain (CPSP) is a central pain arising from a vascular lesion in the central nervous system that elicits somatosensory deficits, often contralateral to stroke lesions. It is expressed as continuous or intermittent pain accompanied by sensory abnormalities like dysesthesia and allodynia. CPSP remains de-emphasized due to the variation in onset and diversity in symptoms, besides the difficulty of distinguishing it from other post-stroke pains, often referred to as a diagnosis of exclusion. Spinothalamic dysfunction, disinhibition of the medial thalamus, and neuronal hyperexcitability combined with deafferentation in thalamocortical regions are the mechanisms underlying central pain, which play a significant role in the pathogenesis of CPSP. The treatment regimen for CPSP seems to be perplexed in nature; however, based on available studies, amitriptyline and lamotrigine are denoted as first-line medications and non-pharmacological choices may be accounted for cases intractable to pharmacotherapy. This review attempts to provide an overview of the mechanisms, existing management approaches, and emerging targets of CPSP. A profound understanding of CPSP aids in optimizing the quality of life among stroke sufferers and facilitates further research to develop newer therapeutic agents for managing CPSP.

Relief of Central Poststroke Pain Affecting Both the Arm and Leg on One Side by Double-independent Dual-lead Spinal Cord Stimulation Using Fast-acting Subperception Therapy Stimulation: A Case Report

Central poststroke pain is a chronic, intractable, central neuropathic pain. Spinal cord stimulation is a neuromodulation therapy for chronic neuropathic pain. The conventional stimulation method induces a sense of paresthesia. Fast-acting subperception therapy is one of the latest new stimulation methods without paresthesia. A case of achieving pain relief of central poststroke pain affecting both the arm and leg on one side by double-independent dual-lead spinal cord stimulation using fast-acting subperception therapy stimulation is presented. A 67-year-old woman had central poststroke pain due to a right thalamic hemorrhage. The numerical rating scale scores of the left arm and leg were 6 and 7, respectively. Using dual-lead stimulation at the Th 9-11 levels, a spinal cord stimulation trial was performed. Fast-acting subperception therapy stimulation achieved pain reduction in the left leg from 7 to 3. Therefore, a pulse generator was implanted, and the pain relief continued for 6 months. Then, two additional leads were implanted at the C 3-5 levels, and pain in the arm decreased from 6 to 4. Independent setting and adjustments of the dual-lead stimulation were required because the thresholds of paresthesia perception were significantly different. To achieve pain relief in both the arm and leg, double-independent dual-lead stimulation placed at cervical and thoracic levels is an effective treatment. Fast-acting subperception therapy stimulation may be effective for central poststroke pain, especially in cases where the paresthesia is perceived as uncomfortable or the conventional stimulation itself is ineffective.

miR‑223 ameliorates thalamus hemorrhage‑induced central poststroke pain via targeting NLRP3 in a mouse model

Central poststroke pain (CPSP) is a central neuropathic pain syndrome that occurs following a stroke and mainly manifests as pain and paresthesia in the body region corresponding to the brain injury area. At present, due to the lack of clinical attention given to CPSP, patients suffer from long-term pain that seriously affects their quality of life. Current literature indicates that microRNA (miR)-223 can impede inflammation and prevent collateral damage. The NLR family pyrin domain containing 3 (NLRP3) inflammasome induces IL-18 and IL-1β secretion and maturation and participates in the inflammatory response. Previous evidence has confirmed that miR-223 can negatively regulate NLRP3 in the development of inflammatory responses. However, whether the miR-223 targeting of NLRP3 is involved in CPSP remains unclear. In the present study, the expression of miR-223 was detected by reverse transcription-quantitative PCR analysis. The expression levels of NLRP3, caspase-1, ASC, IL-18, IL-1β, ERK1/2, p-ERK1/2 and GFAP were detected by western blot analysis. The results demonstrated that thalamic hemorrhagic stroke triggered by microinjection of collagenase Ⅳ (Coll IV) into the ventral posterior lateral (VPL) nucleus results in pain hypersensitivity. miR-223 expression level were significantly reduced in the CPSP model. The expression levels of NLRP3, caspase-1, ASC, IL-18 and IL-1β were significantly increased in the CPSP model. The expression level of GFAP was detected to determine astrocyte activation. The results demonstrated that astrocyte activation induced by Coll IV produced a CPSP model. The p-ERK1/2 expression level was demonstrated to be significantly increased in the CPSP model. The introduction of an miR-223 agomir significantly attenuated thalamic pain and significantly decreased the levels of NLRP3, caspase-1, ASC and proinflammatory cytokines (IL-18 and IL-1β). Furthermore, introducing a miR-223 antagomir into the VPL nucleus of naïve mice mimicked thalamic pain and significantly increased the levels of NLRP3, caspase-1, ASC and proinflammatory cytokine levels (IL-18 and IL-1β). These results indicated that miR-223 inhibited NLRP3 inflammasome activity (caspase-1, NLRP3 and ASC), which ameliorated thalamus hemorrhage-induced CPSP in mice via NLRP3 downregulation. In conclusion, these results may determine the mechanisms underlying CPSP and facilitate development of targeted therapy for CPSP.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

TRIAL REGISTRATION

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

Effects of Pulsed Radiofrequency with Different Temperature on Model Rats of Chronic Constriction Injury

OBJECTIVES

The treatment for neuropathic pain is still a big challenge. Pulsed radiofrequency technique has been widely used to relieve neuropathic pain in recent years. The purpose of this study is to optimize the temperature for pulsed radiofrequency therapy.

DESIGN

Animal, experimental study.

METHODS

Seventy-five male SD rats were randomly divided into five groups: Sham operation group (Sham group), chronic constriction injury group (CCI group), PRF 42°C group (P42 group), PRF 50°C group (P50 group), and PRF 60°C group (P60 group). The hindpaw withdrawal threshold (HWT), paw thermal withdrawal latency (PTWL), sciatic nerve structure, and the concentration of spinal methionine enkephalin(M-ENK) were detected to identify which temperature is the best for PRF treatment.

RESULTS

PRF at 42°C, 50°C and 60°C significantly alleviated the pain in CCI rats. The therapeutic effects of 50°C and 60°C were similar, and both were better than 42°C. In addition, PRF using 42°C, 50°C, and 60°C mediated nerve injury to sciatic nerve were grade 1, 1, and 2, respectively. The concentration of M-ENK in spinal cord increased accompanying with the increasing of the temperature of PRF.

CONCLUSIONS

PRF using 50°C could induce less damage while achieving better improvement of mechanical and thermal pain threshold than 42°C and 60°C in CCI rats, which may be achieved by promoting the expression of M-ENK in spinal cord.

Prevalence and Management Challenges in Central Post-Stroke Neuropathic Pain: A Systematic Review and Meta-analysis

Introduction

Central post-stroke pain (CPSP) is defined as the neuropathic pain that arises either acutely or in the chronic phase of a cerebrovascular event and is a result of central lesions of the somatosensory tract. The aim of this systematic review and meta-analysis was to establish the prevalence of CPSP, to describe its characteristics, and to discuss the associated management challenges.

Methods

After a systematic Medline search, we identified 69 papers eligible to be included.

Results

The pooled prevalence of CPSP in patients with stroke at any location was 11% (95% CI 7–18%), which can increase to more than 50% in the subgroups of patients with medullary or thalamic strokes. CPSP onset coincides with stroke occurrence in 26% of patients (95% CI 18–35%); CPSP manifests within a month since symptom onset in 31% of patients (95% CI 22–42%), and occurs between the first month and the first year in 41% of patients (95% CI 33.9–49.0%). CPSP develops more than 12 months after stroke onset in 5% of patients (95% CI 3–8%).

Conclusions

Clinicians should look for any evidence of central neuropathic pain for at least 12 months after stroke. Both pharmacological and non-pharmacological interventions can be used for the management of CPSP. Lamotrigine has the strongest evidence (Level II of evidence, derived from small randomized controlled trials) for being effective in the management of CPSP. Future research should focus on well-designed trials of pharmacological and non-pharmacological interventions aiming to relief CPSP, which is a very common but often neglected pain syndrome.

Electronic supplementary material

The online version of this article (10.1007/s12325-020-01388-w) contains supplementary material, which is available to authorized users.

Effect of electroacupuncture on relieving central post-stroke pain by inhibiting autophagy in the hippocampus

INTRODUCTION

To explore the underlying mechanism of electroacupuncture (EA) treatment on central post-stroke pain (CPSP), and provide basic evidence for the EA treatment on CPSP.

METHODS

Firstly, 40 male SD rats were successfully established with a model of CPSP, under the intervention of different EA frequencies (2 Hz and 15 Hz) and fluoxetine (5 ml/kg and 0.4 mg/ml), whose brain tissue was then removed for paraffin-embedded sectioning; secondly, LPS induced the primary brain cells in the hippocampus to cause inflammation model which were added NS398 (inhibitor of COX-2) and DKK-1 (inhibitor of β-catenin) later. The lesion sites of brain tissue were observed by Nissl staining and Transmission Electron Microscope (TEM) and autophagy-related proteins (LC3B, p62, LAMP-1), COX-2 and β-catenin were detected by Western Blot and immunohistochemical staining. Finally, the correlation between LC3B, COX-2, and β-catenin was calculated by multispectral quantification.

RESULTS

(1) In the EA group (15 Hz), the number of Nissl bodies increased, autophagy-related protein LC3B-Ⅱ/Ⅰ, LAMP-1, COX-2, and β-catenin was lowly expressed, p62 was highly expressed; (2) COX-2, β-catenin and LC3B are positively correlated with each other (COX-2 & β-catenin: r = 0.923; COX-2 & LC3B: r = 0.818; β-catenin & LC3B: r = 0.801); (3) Nissl bodies of primary brain cells of the hippocampus under LPS were like animal experiments; after addition of DKK-1, high expression of β-catenin and COX-2 induced by LPS was significantly down-regulated, and LC3B-II/I was significantly down-regulated, and p62 protein only had up-regulation trend; after addition of NS398, COX-2 and LC3B-II/I was significantly down-regulated.

CONCLUSION

EA may inhibit autophagy in the hippocampus by reducing β-catenin/COX-2 protein expression and effectively alleviating CPSP.

SIGNIFICANCE STATEMENT

Previous studies have found that EA can reduce the expression of NK-1R in damaged rats by inhibition of COX-2 and β-catenin loops, which controls the activation of glial cells in the damaged area and the apoptosis of neuronal cells, and alleviated pain. In the male SD rat model, we evaluated this effect that EA inhibits autophagy in the hippocampus by reducing β-catenin/COX-2 protein expression in the brain tissue. In addition, we assessed expression levels of autophagy-related proteins and genes on the inflammatory primary brain cells model. From the experiment, we found EA may inhibit autophagy in the hippocampus by reducing β-catenin/COX-2 protein expression. These findings provide a foundation for the interpretation of the mechanism of EA on relieving CPSP in clinical practice.

Predictive Factors Associated with Pain Relief of Spinal Cord Stimulation for Central Post-stroke Pain

The efficacy and predictive factors associated with successful spinal cord stimulation (SCS) for central post-stroke pain (CPSP) have yet to be definitively established. Thus, this study evaluated the rates of pain relief found after more than 12 months and the predictive factors associated with the success of SCS for CPSP. The degree of pain after SCS in 18 patients with CPSP was assessed using the Visual Analog Scale preoperatively, at 1, 6 and 12 months after surgery, and at the time of the last follow-up. After calculating the percentage of pain relief (PPR), patients were separated into two groups. The first group exhibited continuing PPR ≥30% at more than 12 months (effect group) while the second group exhibited successful/unsuccessful trials followed by decreasing PPR <30% within 12 months (no effect group). Pain relief for more than 12 months was achieved in eight out of 18 (44.4%) patients during the 67.3 ± 35.5 month follow-up period. Statistically significant differences were found for both the age and stroke location during comparisons of the preoperative characteristics between the two groups. There was a significantly younger mean age for the effect versus the no effect group. Patients with stoke in non-thalamus were significantly enriched in effect group compared with those with stoke in thalamus. Multivariable analysis using these two factors found no statistical differences, suggesting that these two factors might possibly exhibit the same behaviors for the SCS effect. These results suggest that SCS may be able to provide pain relief in young, non-thalamus stroke patients with CPSP.