Systematic review and network meta-analysis of effects of noninvasive brain stimulation on post-stroke cognitive impairment

Repetitive transcranial magnetic stimulation for cognitive rehabilitation in stroke survivors: A systematic review and meta-analysis of randomized controlled trials

Cognitive impairments are one of the most common consequences in stroke survivors. Repetitive transcranial magnetic stimulation (rTMS) produces electromagnetic pulses transmitted through a coil over the individual's head. This review aims to examine the effects of rTMS on cognition in stroke survivors, identify who would be most likely to benefit from the therapy, define the optimal therapeutic parameters, and provide recommendations. "PubMed, Medline, Scopus, EMBASE, PEDro, and Web of Science" were searched until December 5, 2024. Comprehensive Meta-Analysis version 4 was used for quantitative analysis. The "Cochrane Collaboration tool" was employed to assess the quality of the selected studies. Thirteen studies met the eligibility criteria. In total, 608 stroke survivors (mean age 60.17 years) were involved in the present review. The meta-analysis showed a small, non-significant effect of rTMS on global cognitive function in stroke survivors (Functional independence measure-cognitive; SMD = 0.386, 95% CI: -0.331 to 1.103, p = .291), (Mini-Mental State Examination; SMD = 0.162, 95% CI: -0.405 to 0.730, p = .575), and (Montreal Cognitive Assessment; SMD = 0.204, 95% CI: -0.613 to 1.021, p = .625) with high heterogeneity (I2 = 77-85%). While some studies reported improvements in specific cognitive domains, overall findings indicate substantial variability and uncertainty. This review highlights inconclusive evidence on the effects of rTMS on various cognitive domains in patients with stroke. The frequency of rTMS and coil location are essential factors in determining outcomes. Future studies are strongly warranted.

Transcranial direct current stimulation in individuals with severe traumatic brain injury in the subacute phase: a case series

The aim of this study is to report clinical cases of patients with severe traumatic brain injury (TBI) who underwent transcranial direct current stimulation (tDCS) in the subacute phase. We hypothesize that tDCS will improve the functional and cognitive recovery of patients. 5 men, admitted with severe TBI, and Glasgow Coma Scale (GCS) score ≤ 8 on admission or at some point during hospitalization, were in the subacute phase of the trauma (between 2 and 16 weeks). Participants received 5 sessions of tDCS every day. The results were measured at the beginning and at the end of the 5 sessions. The application of tDCS with an active electrode (anode) was applied to the region of the left dorsolateral prefrontal cortex (LPFC - F3) and the cathode was positioned over the contralateral supraorbital area. Clinical outcomes were measured through cognitive assessment, Mini Mental State Examination (MMSE), mental health and depression, Hospital Anxiety and Depression Scale (HADS-A), pain, visual analogue scale (VAS), Functional Independence Measure (FIM), Rancho Los Amigos Scale (RLAS) and Glasgow Outcome Scale - Extended (GOS-E), were applied to classify the patient's condition. For characteristics of participants and findings results, descriptive statistics were presented as mean ± Standard Deviation (SD). The results after the tDCS intervention show substantial improvement in the assessed. The research demonstrates the potential benefits of using tDCS in patients with TBI, but also provides a practical basis for applying these techniques in clinical settings.

Remotely Supervised Transcranial Direct Current Stimulation in Post-Stroke Recovery: A Scoping Review

Background and Objectives: Stroke is a leading cause of disability worldwide. Recent studies have suggested the feasibility and potential utility of remotely supervised transcranial direct current stimulation (RS-tDCS) to improve different types of impairments in various neurological conditions. This scoping review provides a critical appraisal of RS-tDCS as an adjunct therapy to enhance recovery after stroke. Materials and Methods: A comprehensive literature review was systematically conducted using PubMed through Nested Knowledge software. A supplementary search was conducted in Google Scholar. Two independent authors screened and identified related studies investigating RS-tDCS in patients with stroke from inception to February 2025. Results: Studies showed that RS-tDCS was safe, with only mild side effects. Additionally, it was feasible, with high adherence rates likely due to ease of use. Regarding efficacy, RS-tDCS preliminarily yielded improvements in upper- and lower-limb motor functions and increased language and cognitive performance. However, the studies were underpowered and heterogeneous, limiting generalization of findings. Conclusions: RS-tDCS is safe and feasible, affording beneficial effects in the motor, language, and cognitive functions of patients with post-stroke impairments. RS-tDCS has the potential to improve access and reduce disparities for post-stroke experimental treatments. However, adequately powered randomized trials are needed to further investigate the efficacy.

Can non-motor outcomes be improved in chronic stroke? A systematic review on the potential role of non-invasive brain stimulation

BACKGROUND

Non-invasive brain stimulation induces changes in spontaneous neural activity in the cerebral cortex through facilitatory or inhibitory mechanisms, relying on neuromodulation of neural excitability to impact brain plasticity. This systematic review assesses the state-of-the art and existing evidence regarding the effectiveness of NIBS in cognitive recovery among patients with chronic stroke.

MATERIALS AND METHODS

We conducted a systematic search, following PRISMA guidelines, for articles published from January 2010 through September 2023. We searched the following databases: PubMed, Embase, Cochrane Database of Systematic Reviews, PEDro, Rehab Data, and Web of Science.

RESULTS

Our electronic searches identified 109 papers. We assessed and included 61 studies based on their pertinence and relevance to the topic. After reading the full text of the selected publications and applying predefined inclusion criteria, we excluded 32 articles, leaving 28 articles for our qualitative analysis. We categorized our results into two sections as follows: (1) Cognitive and emotional domains (11 studies), (2) language and speech functions (16 studies).

CONCLUSION

Our findings highlight the potential of NIBS, such as tDCS and rTMS, in the cognitive, linguistic, and emotional recovery of post-stroke patients. Although it seems that NIBS may work as a complementary tool to enhance cognitive and communication abilities in patients with stroke -also in the chronic phase- evidence on behavioural outcomes is still poor. Future studies should focus on this important issue to confirm the effectiveness of neuromodulation in chronic neurological diseases. PROSPERO Registration: CRD42023458370.

Effect of tDCS combined with virtual reality for post-stroke cognitive impairment: a randomized controlled trial study protocol

BACKGROUND

Post-stroke cognitive impairment (PSCI) not only increases patient mortality and disability, but also adversely affects motor function and the ability to perform routine daily activities. Current therapeutic approaches for, PSCI lack specificity, primarily relying on and medication and traditional cognitive therapy supplemented by a limited array of tools. Both transcranial direct current stimulation (tDCS) and virtual reality (VR) training have demonstrated efficacy in improving cognitive performance among PSCI patients. Previous findings across various conditions suggest that implementing a therapeutic protocol combining tDCS and VR (tDCS - VR) may yield superior in isolation. Despite this, to our knowledge, no clinical investigation combining tDCS and VR for PSCI rehabilitation has been conducted. Thus, the purpose of this study is to explore the effects of tDCS - VR on PSCI rehabilitation.

METHODS

This 4-week, single-center randomized clinical trial protocol will recruit 200 patients who were randomly assigned to one of four groups: Group A (tDCS + VR), Group B (tDCS + sham VR), Group C (sham tDCS + VR), Group D (sham tDCS + sham VR). All four groups will receive conventional cognitive rehabilitation training. The primary outcome measurement utilizes the Mini-Mental State Examination (MMSE). Secondary outcome measures include the Montreal Cognitive Assessment, Frontal Assessment Battery, Clock Drawing Test, Digital Span Test, Logic Memory Test, and Modified Barthel Index. Additionally, S-YYZ-01 apparatus for diagnosis and treating language disorders assesses subjects' speech function. Pre- and post-four-week intervention assessments are conducted for all outcome measures. Functional near-infrared spectroscopy (fNIRS) is employed to observe changes in oxygenated hemoglobin (HbO), deoxy-hemoglobin (HbR), and total hemoglobin (HbT) in the cerebral cortex.

DISCUSSION

Our hypothesis posits that the tDCS - VR therapy, in opposed to individual tDCS or VR interventions, could enhance cognitive function, speech ability and daily living skills in PSCI patients while concurrently augmenting frontal cortical activity. This randomized study aims to provide a robust theoretical foundation supported by scientific evidence for the practical implementation of the tDCS - VR combination as a secure and efficient PSCI rehabilitation approach.

TRIAL REGISTRATION

Chictr.org.cn Identifier: ChiCTR2300070580. Registered on 17th April 2023.

The effect of intermittent theta burst stimulation for cognitive dysfunction: a meta-analysis

BACKGROUND

Growing evidence suggests that cognitive dysfunction significantly impacts patients' quality of life. Intermittent theta burst stimulation (iTBS) has emerged as a potential intervention for cognitive dysfunction. However, consensus on the iTBS protocol for cognitive impairment is lacking.

METHODS

We conducted searches in the Cochrane Central Register of Controlled Trials, EMBASE, PubMed, Chinese National Knowledge Infrastructure, Wanfang Database and the Chongqing VIP Chinese Science and Technology Periodical Database from their inception to January 2024. Random-effects meta-analyzes were used to calculate standardized mean differences and 95% confidence intervals. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation approach.

RESULTS

Twelve studies involving 506 participants were included in the meta-analysis. The analysis showed a trend toward improvement of total cognitive function, activities of daily living and P300 latency compared to sham stimulation in patients with cognitive dysfunction. Subgroup analysis demonstrated that these effects were restricted to patients with post-stroke cognitive impairment but not Alzheimer's disease or Parkinson's disease. Furthermore, subthreshold stimulation also exhibited a significant improvement.

CONCLUSIONS

The results suggest that iTBS may improve cognitive function in patients with cognitive dysfunction, although the quality of evidence remains low. Further studies with better methodological quality should explore the effects of iTBS on cognitive function.

Assessment of noninvasive brain stimulation interventions in Parkinson's disease: a systematic review and network meta-analysis

A network meta-analysis of randomized controlled trials was conducted to compare and rank the effectiveness of various noninvasive brain stimulation (NIBS) for Parkinson's disease (PD). We searched PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), and Chinese Biomedical Literature Service System (SinoMed) databases from the date of database inception to April 30th, 2024. Two researchers independently screened studies of NIBS treatment in patients with PD based on inclusion and exclusion criteria. Two researchers independently performed data extraction of the included studies using an Excel spreadsheet and assessed the quality of the literature according to the Cochrane Risk of Bias Assessment Tool (RoB2). Network meta-analysis was performed in StataMP 17.0. A total of 28 studies involving 1628 PD patients were included. The results showed that HF-rTMS over the SMA (SMD = - 2.01; 95% CI [- 2.87, - 1.15]), HF-rTMS over the M1 and DLPFC (SMD = - 1.80; 95% CI [- 2.90, - 0.70]), HF-rTMS over the M1 (SMD = - 1.10; 95% CI [- 1.55, - 0.65]), a-tDCS over the DLPFC (SMD = - 1.08; 95% CI [- 1.90, - 0.27]), HF-rTMS over the M1 and PFC (SMD = - 0.92; 95% CI [- 1.71, - 0.14]), LF-rTMS over the M1 (SMD = - 0.72; 95% CI [- 1.17, - 0.28]), and HF-rTMS over the DLPFC (SMD = - 0.70; 95% CI [- 1.21, - 0.19]) were significantly improved motor function compared with sham stimulation. The SUCRA three highest ranked were HF-rTMS over the SMA (95.1%), HF-rTMS over the M1 and DLPFC (89.6%), and HF-rTMS over the M1 (73.0%). In terms of enhanced cognitive function, HF-rTMS over the DLPFC (SMD = 0.80; 95% CI [0.03,1.56]) was significantly better than sham stimulation. The SUCRA three most highly ranked were a-tDCS over the M1 (69.8%), c-tDCS over the DLPFC (66.9%), and iTBS over the DLPFC (65.3%). HF-rTMS over the M1 (SMD = - 1.43; 95% CI [- 2.26, - 0.61]) and HF-rTMS over the DLPFC (SMD = - 0.79; 95% CI [- 1.45, - 0.12)]) significantly improved depression. The SUCRA three highest ranked were HF-rTMS over the M1 (94.1%), LF-rTMS over the M1 (71.8%), and HF-rTMS over the DLPFC (69.0%). HF-rTMS over the SMA may be the best option for improving motor symptoms in PD patients. a-tDCS and HF-rTMS over the M1 may be the NIBS with the most significant effects on cognition and depression, separately.Trial registration: International Prospective Register of Systematic Review, PROSPERO (CRD42023456088).

Efficacy of intermittent theta burst stimulation (iTBS) on post-stroke cognitive impairment (PSCI): a systematic review and meta-analysis

BACKGROUND

Stroke is a significant global cause of mortality and morbidity, and post-stroke cognitive impairment (PSCI) affects up to half of stroke patients. Despite the availability of pharmacological and non-pharmacological interventions, there is a lack of definitive effective treatments for PSCI. Non-invasive brain stimulation, particularly intermittent theta burst stimulation (iTBS), has emerged as a promising therapy for the treatment of PSCI.

OBJECTIVE

This systematic review and meta-analysis aimed to evaluate the efficacy and safety of iTBS in enhancing cognitive function among patients with PSCI.

METHODS

A comprehensive search was conducted across multiple databases, including PubMed, Web of Science, Scopus, Cochrane Library, and CNKI, to identify relevant randomized controlled trials published before April 2023. The primary outcome measured changes in global cognitive scales, while the secondary outcomes focused on improvements in attention, orientation, visual-spatial perception, and activities of daily living.

RESULTS

The meta-analysis encompassed six studies involving 325 patients. The results demonstrated that iTBS led to a significant improvement in global cognitive scales (SMD = 1.12, 95% CI = [0.59 to 1.65], P < 0.0001), attention (SMD = 0.48, 95% CI [0.13 to 0.82], P = 0.007), visual perception (SMD = 0.99, 95% CI [0.13 to 1.86], P = 0.02), and activities of daily living (SMD = 0.82, 95% CI [0.55 to 1.08], P < 0.00001). However, there was no significant effect on orientation (SMD = 0.36, 95% CI [- 0.04 to 0.76], P = 0.07). Subgroup analysis based on the number of sessions was conducted, revealing a significant improvement in global cognition among patients with PSCI across the three categories (10 sessions, 20 sessions, and 30 sessions) with no between-group difference (P = 0.28). None of the included studies reported any serious adverse effects.

CONCLUSION

In conclusion, iTBS appears to be a safe and effective non-invasive treatment that can enhance the cognitive abilities and daily living skills of patients with post-stroke cognitive impairment. However, our conclusion is constrained by the limited number of studies. Further high-quality, large-sample RCTs with extended follow-up periods are necessary to validate these findings. Integrating iTBS with brain imaging techniques, such as functional near-infrared spectroscopy and functional magnetic resonance, could aid in understanding the mechanism of iTBS action.

Efficacy of repetitive transcranial magnetic stimulation in post-stroke cognitive impairment: an overview of systematic reviews

OBJECTIVE

The reliability of clinical evidence depends on high-quality meta-analyses/ systematic reviews (MAs/SRs). However, there has been no assessment of the quality of MAs/SRs for repetitive transcranial magnetic stimulation (rTMS) in post-stroke cognitive impairment (PSCI), both nationally and internationally. This article seeks to use radar plotting to visually present the quality of MAs/SRs on rTMS for improving cognitive function in PSCI, aiming to offer an intuitive foundation for clinical research.

METHODS

Eight Chinese or English databases were systematically searched to collect comprehensive literature, and the retrieval time ranged from inception to 26 March 2024. Literature ranking was calculated using six dimensions: publication year, design type, AMSTAR-2 score, PRISMA score, publication bias, and homogeneity. Finally, radar plots were drafted to present a multivariate literature evaluation. The GRADE tool assessed the strength of evidence for the outcome indicators included in the MAs/SRs.

RESULTS

The 17 articles included had average scores of 12.29, 17, 9.88, 9.71, 12.88, and 12.76 for each dimension. The radar plot showed that an article published in 2023 had the highest rank and a large radar plot area, while an article published in 2021 had the lowest rank and a small radar plot area. The GRADE tool evaluation revealed that 51 pieces of evidence were of very low quality, 67 were of low quality, 12 were of moderate quality, and only one was of high quality.

CONCLUSION

The average rank score of literature ranged from 8.50 to 17, with higher rankings indicating greater significance in literature reference. Variations in literature quality were attributed to inadequate study planning, irregular literature search and screening, insufficient description of inclusion criteria for studies, and inadequate consideration of bias risk in the included studies. Most MAs/SRs indicated that rTMS was more effective than the control group in enhancing the global cognitive function and activities of daily living in PSCI patients. However, the overall quality of the literature was generally low and needs validation from future high-quality evidence.Systematic review registration:https://www.crd.york.ac.uk/prospero/, identifier CRD42023491280.

Effect of transcranial direct current stimulation combined with transcutaneous auricular vagus nerve stimulation on poststroke cognitive impairment: a study protocol for a randomised controlled trial

INTRODUCTION

Poststroke cognitive impairment is a common complication in stroke survivors, seriously affecting their quality of life. Therefore, it is crucial to improve cognitive function of patients who had a stroke. Transcranial direct current stimulation (tDCS) and transcutaneous auricular vagus nerve stimulation (taVNS) are non-invasive, safe treatments with great potential to improve cognitive function in poststroke patients. However, further improvements are needed in the effectiveness of a single non-invasive brain stimulation technique for cognitive rehabilitation. This study protocol aims to investigate the effect and neural mechanism of the combination of tDCS and taVNS on cognitive function in patients who had a stroke.

METHODS AND ANALYSIS

In this single-centre, prospective, parallel, randomised controlled trial, a total of 66 patients with poststroke cognitive impairment will be recruited and randomly assigned (1:1:1) to the tDCS group, the taVNS group and the combination of tDCS and taVNS group. Each group will receive 30 min of treatment daily, five times weekly for 3 weeks. Primary clinical outcome is the Montreal Cognitive Assessment. Secondary clinical outcomes include the Mini-Mental State Examination, Stroop Colour Word Test, Trail Marking Test, Symbol Digit Modalities Test and Modified Barthel Index. All clinical outcomes, functional MRI and diffusion tensor imaging will be measured at preintervention and postintervention.

ETHICS AND DISSEMINATION

The trial has been approved by the Ethics Committee of the First Affiliated Hospital of Yangtze University (approval no: KY202390). The results will be submitted for publication in peer-reviewed journals or at scientific conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2300076632.

Mesenchymal Stem Cells for the Treatment of Spinal Cord Injury in Rat Models: A Systematic Review and Network Meta-Analysis

Transplantation of mesenchymal stem cells (MSCs) is one of the hopeful treatments for spinal cord injury (SCI). Most current studies are in animals, and less in humans, and the optimal transplantation strategy for MSCs is still controversial. In this article, we explore the optimal transplantation strategy of MSCs through a network meta-analysis of the effects of MSCs on SCI in animal models. PubMed, Web of Science, Cochrane Library, Embase, China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal Database (VIP), and Chinese Biomedical Literature Service System (SinoMed) databases were searched by computer for randomized controlled studies on MSCs for SCI. Two investigators independently completed the literature screening and data extraction based on the inclusion and exclusion criteria. RevMan 5.4 software was used to assess the quality of the included literature. Stata 16.0 software was used for standard meta-analysis and network meta-analysis. Standardized mean difference (SMD) was used for continuous variables to combine the statistics and calculate 95% confidence interval (95% CI). P < 0.05 was considered a statistically significant difference. Cochrane's Q test and the I2 value were used to indicate the magnitude of heterogeneity. A random-effects model was used if I2 > 50% and P < 0.10 indicated significant heterogeneity between studies, and conversely, a fixed-effects model was used. Evidence network diagrams were drawn based on direct comparisons between various interventions. The surface under the cumulative ranking curve area (SUCRA) was used to predict the ranking of the treatment effects of each intervention. A total of 32 animal studies were included in this article for analysis. The results of the standard meta-analysis showed that MSCs improved motor ability after SCI. The network meta-analysis showed that the best treatment effect was achieved for adipose tissue-derived mesenchymal stromal cells (ADMSCs) in terms of cell source and intrathecal (IT) in terms of transplantation modality. For transplantation timing, the best treatment effect was achieved when transplantation was performed in the subacute phase. The available literature suggests that IT transplantation using ADMSCs in the subacute phase may be the best transplantation strategy to improve functional impairment after SCI. Future high-quality studies are still needed to further validate the results of this study to ensure the reliability of the results.

Pre-treatment frontal beta events are associated with executive dysfunction improvement after repetitive transcranial magnetic stimulation for depression: A preliminary report

Repetitive transcranial magnetic stimulation (rTMS) is an established clinical treatment for major depressive disorder (MDD) that has also been found to improve aspects of executive functioning. The objective of this study was to examine whether oscillatory burst-like events within the beta band (15-29 Hz) prior to treatment could predict subsequent change in self-reported executive dysfunction (EDF) across a clinical course of rTMS for MDD. Twenty-eight adults (64% female) with MDD completed the self-report Frontal Systems Behavior Scale (FrSBe) and provided eyes-closed resting-state electroencephalography (EEG) before and after a clinical course of rTMS therapy for primary MDD. The rate, power, duration, and frequency span of transient EEG measured oscillatory beta events were calculated. Events within delta/theta and alpha bands were examined to assess for beta specificity. After controlling for improvement in primary depressive symptoms, a lower rate of beta events at F3, Fz, F4, and Cz prior to rTMS treatment was associated with a larger improvement in EDF after rTMS treatment. In addition, a decrease in beta event rate at Fz pre-to-post treatment was associated with a larger improvement in EDF after treatment. Results were largely specific to the beta band. In this study, the rate of frontrocentral beta events prior to treatment significantly predicted the likelihood of subsequent improvement in EDF symptoms following a clinical course of rTMS for MDD. These preliminary findings suggest the potential utility of EEG measured beta events and rTMS for targeting EDF across an array of neuropsychiatric disorders.

Brain State-Dependent Non-Invasive Neurostimulation with EEG Feedback: Achievements and Prospects (Review)

Non-invasive brain stimulation with electroencephalogram (EEG) feedback is an intensively developing and promising area of neurophysiology. The review considers the literature data over the past 5 years on the achievements and promising directions for the further development of this research line. Modern data on the developed approaches to the practical use of various types of brain state-dependent adaptive neurostimulation with EEG feedback were analyzed. The main attention is paid to the studies using non-invasive magnetic and electrical stimulation, as well as acoustic and audiovisual stimulation. The paper considers the possibilities and prospects for using these technologies in clinical medicine. The results of the authors' own research are presented.

Current evidence, clinical applications, and future directions of transcranial magnetic stimulation as a treatment for ischemic stroke

Transcranial magnetic stimulation (TMS) is a non-invasive brain neurostimulation technique that can be used as one of the adjunctive treatment techniques for neurological recovery after stroke. Animal studies have shown that TMS treatment of rats with middle cerebral artery occlusion (MCAO) model reduced cerebral infarct volume and improved neurological dysfunction in model rats. In addition, clinical case reports have also shown that TMS treatment has positive neuroprotective effects in stroke patients, improving a variety of post-stroke neurological deficits such as motor function, swallowing, cognitive function, speech function, central post-stroke pain, spasticity, and other post-stroke sequelae. However, even though numerous studies have shown a neuroprotective effect of TMS in stroke patients, its possible neuroprotective mechanism is not clear. Therefore, in this review, we describe the potential mechanisms of TMS to improve neurological function in terms of neurogenesis, angiogenesis, anti-inflammation, antioxidant, and anti-apoptosis, and provide insight into the current clinical application of TMS in multiple neurological dysfunctions in stroke. Finally, some of the current challenges faced by TMS are summarized and some suggestions for its future research directions are made.