Search Results (79)

Background/Objectives: Stroke is a sudden neurological event caused by disrupted cerebral blood flow and represents a leading cause of acquired disability worldwide. Motor impairments and spasticity are among the most prevalent sequelae, significantly limiting functional independence and quality of life. Non-invasive electrotherapy has emerged as a complementary strategy in neurorehabilitation aimed at enhancing neuroplasticity and improving motor recovery. To systematically review current evidence regarding the effectiveness of non-invasive electrotherapy modalities in the rehabilitation of motor sequelae and spasticity following stroke, and to examine their theoretical and clinical rationale. Methods: A systematic literature review was conducted in accordance with PRISMA 2020 guidelines. The protocol was prospectively registered in the Open Science Framework (OSF). A comprehensive search was performed in Pubmed, Web of Science (WoS), and Scopus for studies published up to 14 November 2023, using the terms “Electric Stimulation Therapy” and “Stroke”. The methodological quality was assessed using the PEDro scale. The levels of evidence were classified according to the Oxford Centre for Evidence-Based Medicine criteria, and the risk of bias was evaluated using the Cochrane Risk of Bias tool (RoB 2). Results: Sixteen studies were included in the review. The analyzed interventions comprised neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), functional electrical stimulation (FES), neuromuscular electrical stimulation combined with transcranial magnetic stimulation (NMES + rTMS), transcranial direct current stimulation (tDCS), and afferent electrical stimulation (AES). Overall, the methodological quality of the included studies ranged from moderate to high, with PEDro scores between 6 and 9 out of 10. According to the Oxford Centre for Evidence-Based Medicine classification, most studies corresponded to level 1b evidence, while a smaller proportion were classified as level 2b. A risk of bias assessment using the Cochrane RoB 2 tool showed that the majority of the included studies presented a low risk of bias across most domains, although some concerns were identified in the domains of randomization and measurement in a limited number of trials. Across modalities, consistency within group improvement in motor function and spasticity was reported. However, between group comparisons with conventional rehabilitation were often inconsistent and did not consistently demonstrate superiority. The variability in stimulation parameters, intervention duration, and outcome measures further limited direct comparisons across studies. Conclusions: Non-invasive electrotherapy appears to be a safe and promising adjunct to conventional stroke rehabilitation. Nevertheless, further high-quality studies are required to clarify the underlying neurophysiological mechanisms and to establish standardized treatment protocols. Full article

Background: Transcranial direct current stimulation (tDCS) involves the application of weak electric currents (typically 0.5–2 mA) via scalp electrodes to promote neuroplastic changes that modulate behaviour or cortical activity. Although there have been promising results in eliminating tinnitus or reducing its loudness or severity, there is also a high degree of inter-individual variability. This may be due to anatomical differences and their influence on the resulting electric field. To optimise and personalise tDCS protocols, computational electric field models based on individual clinical imaging may be utilised to give insight into the induced electric field during tDCS and inform more effective protocols for targeted stimulation. To our knowledge, there are currently no standards for current modelling or reviews which detail the optimal parameters for conducting current modelling studies for tDCS. Objectives: The aim of this review is to investigate the methodology of current modelling studies for tDCS so that informed, personalised protocols can be designed by modelling the electric field of the brain during tDCS for tinnitus. By considering the impact of individual anatomical differences on the electric field induced by tDCS, targeted protocols could be developed to reduce tinnitus loudness and severity in a systematic and predictable way. Design: The protocol for this review is based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) Checklist. Using online databases, records were identified based on a keyword search for records relevant to current modelling for tDCS, including peer-reviewed papers, clinical trials, the grey literature, theses, dissertations, and conference abstracts. Four thousand two hundred and fifty-three records were retrieved from thirteen online databases and include 4186 records from the initial search completed between May and July 2024, and 67 records from an updated search completed in August 2025. A further 596 records were retrieved from Google Scholar (501 from the initial search and 95 from the updated search). One hundred and fourteen records met our criteria for inclusion. Each record was charted by two separate reviewers, with attention to the modelling pipeline and predicted values in peak and range of electric field magnitude. Results: There was a consensus that, despite model parameters and pipelines, there was inter-individual variability in the predicted electric fields. The reviewed records highlighted the impact of individual differences, including age, sex, and anatomical variation, on the predicted electric field during tDCS. Increased age was often associated with age-related brain atrophy and high relative cerebrospinal fluid volume, which was a significant influence on the resulting E-field intensity and distribution. Conclusions: When creating personalised tDCS protocols for tinnitus, the model parameters and sources of variability (i.e., morphology, age, and sex) should be carefully considered to achieve the desired stimulation outcomes, particularly in regard to applied current intensity. Full article

Background/Objectives: Transcranial electrical stimulation (tES) shows potential for enhancing attention and learning, yet its effects in applied contexts remain underexplored. This study investigated whether transcranial direct current stimulation (tDCS) either alone or in combination with high-frequency transcranial random noise stimulation (hf-tRNS) over the right inferior frontal gyrus (rIFG) could enhance performance in a visual search task requiring target identification and change detection, compared with a low-current control condition. Methods: Sixty-four participants were randomly assigned to receive tDCS alone (2.0 mA), tDCS with hf-tRNS (1.8 mA DC offset combined with 100–500 Hz noise at ±0.18 mA), or low-current control stimulation during training. The task involved identifying vehicles and detecting changes between image presentations. Performance accuracy and EEG oscillatory power were assessed at baseline and post-stimulation. Results: ANCOVA revealed significant effects of stimulation on target identification accuracy (F(2,60) = 3.27, p = 0.045, ηp² = 0.098), with tDCS showing greater improvement than the low-current control condition (p = 0.017). No significant effects were found for change detection for any stimulation condition, or for either the target or change detection for hf-tRNS. Baseline performance moderated stimulation effects: low performers receiving tDCS showed the greatest improvements (F(2,26) = 3.80, p = 0.036, ηp² = 0.226), surpassing even high-baseline performers post-training. EEG analyses revealed that participants who showed greater decreases in frontal theta power demonstrated larger improvements in accuracy with tDCS alone (r = −0.634, p = 0.005) but not with hf-tRNS or the control. Conclusions: tDCS over rIFG selectively enhanced target identification accuracy in a complex visual search, particularly benefiting individuals with lower-baseline performance. These findings suggest tDCS may facilitate training in lower-performing novice populations. Full article

Major depressive disorder (MDD) continues to be a primary cause of disability globally, with a significant number of patients exhibiting resistance to standard pharmacological and psychotherapeutic interventions. In recent years, non-invasive brain stimulation techniques, especially transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), have emerged as promising therapies for treatment-resistant MDD. A comprehensive search was performed in PubMed, which included all studies published over the last ten years. Eligible studies encompassed both animal models and clinical investigations. This review provides a comparative overview of transcranial electrical stimulation modalities, with a focus on their mechanisms of action, clinical efficacy, and underlying neurobiological mechanisms. We pay particular attention to the role of the neurotrophin system, specifically brain-derived neurotrophic factor (BDNF), in mediating the treatment effects of transcranial stimulation. Recent findings indicate that neuromodulation could improve neuroplasticity by increasing BDNF levels and associated signaling pathways, which may help stabilize mood and enhance the improvement of individuals with MDD. A more profound understanding of these mechanisms could lead to more precise, biomarker-driven interventions. Further research is essential to elucidating the long-term effects of brain stimulation on neurotrophin levels and to creating more individualized treatment strategies. Full article

Transcranial direct current stimulation (tDCS) is a noninvasive form of brain stimulation that involves passing a weak electrical current between electrodes on the scalp to modulate underlying neural tissue. TDCS has been shown to modulate cognition in a variety of domains, including memory, attention, and visual processing. Prior work from our laboratory has shown positive effects of tDCS on learning to detect target objects hidden in complex naturalistic visual scenes and learn rules for categorizing images, though the mechanism for these benefits remains unknown. One possibility is that tDCS optimizes visual search by modulating visual attention or via the reduction in search errors. One method of quantifying visual attention is to use eye tracking to record search patterns to determine if and how visual search is adjusted under verum stimulation conditions. Eye tracking data allows classification of errors into error types, including sampling errors (failing to look in the relevant region), recognition errors (looking at the critical portion of a scene, but failing to recognize it as such as evidenced by visual fixation), and decision-making errors (fixating on the relevant portion of a scene, but making the wrong determination). Our results indicate that the benefit tDCS confers on visual search for targets stems from the reduction in decision-making errors when targets are present (Cohen’s d = 0.86). Also reported is a replication of previous findings showing a tDCS-dependent improvement in learning this task, learning score (Cohen’s d = 0.88); d’ (Cohen’s d = 1.00). This provides support for moving tDCS into the application space by pairing it with analysts who are concerned with the type of search error that is corrected via stimulation. Full article

Swallowing is mediated by the central nervous system, including cortical and subcortical structures, the cerebellum, and the brainstem. The brainstem contains the swallowing centre that is crucial for initiating and coordinating swallowing. Consequently, brainstem damage due to stroke often leads to severe and persistent dysphagia. The aim of the present narrative review is to provide an overview of dysphagia following brainstem stroke and its management. It summarizes the physiology and pathophysiology of dysphagia following brainstem stroke and the available therapeutic options, and evaluate their effectiveness for dysphagia following brainstem stroke, which would promote the development of therapeutic protocols. Neuromodulatory techniques, including pharyngeal electrical stimulation (PES), repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS), modulate the excitability of corticobulbar circuits. These techniques promote neuroplasticity through peripheral or cortical electrical or electromagnetic inputs. Skill-based swallowing training emphasizes cortical involvement in enhancing swallowing skill, offering a targeted approach to behavioural rehabilitation. Finally, transient receptor potential (TRP) agonists increase sensory inputs to the swallowing system by stimulating the sensory receptors in the oropharynx, potentially activating the swallowing network. While these options have shown promise in dysphagia rehabilitation following stroke, most the available data comes from patients with mixed stroke lesions, with limited data focused specifically on brainstem lesions. Therefore, the evidence for their efficacy in patients with brainstem stroke remains underexplored. Therefore, treatment decisions should rely on the understanding of swallowing physiology, neuroplasticity, and clinical evidence from related stroke populations. Full article

Objectives: This review seeks to evaluate the effectiveness of electrical stimulation (ES) in improving upper limb function in children and young people (CYP) with hemiplegic cerebral palsy (HCP). Methods: A systematic literature search from inception until May 2025 was conducted. Various study designs comparing the effect of different ES techniques such as functional electrical stimulation (FES), transcutaneous electrical nerve stimulation (TENS), neuromuscular electrical stimulation (NMES), transcutaneous spinal cord stimulation (TSCS), and transcranial direct current stimulation (tDCS) on upper limb function in CYP with HCP were included. Results: Eighteen studies were selected for review and quality assessment, comprising twelve randomised controlled trials (RCTs) and six non-RCTs. FES was shown to improve upper limb function, though more rigorous and controlled research is needed. Both TENS and NMES demonstrate potential to improve upper limb function, particularly when combined with other interventions. The analysis suggests that variability in reporting tDCS outcomes hinders assessment of its potential benefits for improving upper limb function. Conclusions: Current research suggests ES may support upper limb rehabilitation in CYP with HCP, though the overall evidence remains limited. Most studies are small, underpowered, and lack long-term follow-up, limiting confident conclusions. ES should therefore be applied cautiously and only as part of a comprehensive rehabilitation plan. Full article

Background and Objectives: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease affecting the upper and lower motor neurons, with a bleak prognosis and few treatment options. Non-invasive brain stimulation (NIBS) techniques, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), represent emerging approaches aimed at modulating cortical hyperexcitability, a relevant pathogenetic mechanism in ALS. Materials and Methods: A systematic review of the literature was conducted following the PRISMA guidelines, exploring the Scopus and PubMed databases from April to June 2025 with terms related to ALS and NIBS. A total of 18 relevant studies were selected from the initial 708 articles, analysing stimulation protocols, clinical and neurophysiological outcomes, and associated biomarkers; their validity was assessed using the revised Cochrane risk-of-bias (RoB2) tool. Results: The selected studies were extremely heterogeneous, with NIBS techniques, including magnetic (rTMS, cTBS, tSMS) and electrical (tDCS) stimulation, showing variable effects. Low-frequency protocols (1 Hz rTMS) and cTBS showed a slight slowing of clinical progression, while prolonged home stimulation with tDCS and tSMS showed more significant improvements in terms of efficacy, tolerability, and adherence. The main limitations concern the heterogeneity of patients and protocols and the lack of standardised biomarkers, which is why the analysis remained at a descriptive level. The use of telemonitoring and caregiver training are essential to ensure safety and accessibility. Conclusions: NIBS represents a promising therapeutic approach for ALS, but further multicentre, standardised studies with prolonged follow-up are needed. Future strategies should include customisation of stimulation, combination with other therapies, and extension of application to pre-symptomatic phases. Full article

This systematic review examines the combined use of electroencephalography (EEG) and transcranial electrical stimulation (tES) in both clinical and healthy populations. The review focuses on EEG’s role in guiding, monitoring, and evaluating tES interventions and assesses the generalizability of EEG responses to different tES protocols. A comprehensive search across Google Scholar, PubMed, Scopus, IEEE Xplore, ScienceDirect, and Web of Science identified 162 relevant studies using the query: “EEG AND (tDCS OR transcranial direct current stimulation OR tACS OR transcranial alternating current stimulation OR tRNS OR transcranial random noise stimulation OR tPCS OR transcranial pulsed current stimulation)”. Quality was assessed using the Quality Assessment Tool for Quantitative Studies (QATQS). Most studies used EEG post tES to assess neuromodulatory effects, with fewer studies using EEG for protocol design or incorporating real-time EEG for adaptive stimulation. Some studies integrated EEG both before and after stimulation, but considerable heterogeneity in tES parameters and EEG metrics limited reproducibility and comparability. Many studies reported non-significant EEG changes despite standardized approaches. Methodological quality was generally low, and the link between EEG changes and clinical outcomes remains unclear. The findings underscore the potential of EEG-informed, personalized tES protocols, though the use of real-time closed-loop systems remains a limited approach in current research. Full article

Background/Objectives: Neck pain is defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, affecting the cervical region. It represents one of the leading causes of disability, with a prevalence of 30%. Transcranial direct current stimulation (tDCS) is a non-invasive electrotherapy technique that enables direct modulation of cortical excitability. It involves the application of a low-intensity electrical current to the scalp, targeting the central nervous system. The aim of this study was to analyze the effects of tDCS on functionality, pain, mobility, and pressure pain threshold in patients with chronic nonspecific neck pain. Methods: Thirty participants (18–60 years) were selected to receive ten treatment sessions over a four-week period using tDCS (CG = 15) or transcutaneous electrical nerve stimulation (TENS) (CG = 15), with the following various related variables evaluated: functionality (Neck Disability Index), pain intensity (NPRS), cervical range of motion (ROM), and pressure pain threshold (PPT). Assessments were conducted at baseline, post-treatment, one month, and three months after the intervention. Results: The within-group analysis revealed statistically significant improvements for both groups at post-treatment, one-month follow-up, and three-month follow-up. Conclusions: The comparison between groups shows favorable changes in the tDCS group for PPT measurements. Full article

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique promisingly used to treat neurological and psychological disorders. Nevertheless, the inter-subject heterogeneity in its after-effects frequently limits its efficacy. This can be attributed to fixed-dose methods, which do not consider inter-subject anatomical variations. This work attempts to overcome this constraint by examining the effects of age and anatomical features, including the volume of cerebrospinal fluid (CSF), the thickness of the skull, and the composition of brain tissue, on electric field distribution and cortical excitability. A computational approach was used to map the electric field distribution over the brain tissues of realistic head models reconstructed from MRI images of twenty-three subjects, including adults and children of both genders. Significant negative correlations (p < 0.05) were found in the data between the maximum electric field strength and anatomical variable parameters. Furthermore, this study showed that the percentage of brain tissue exposed to an electric field amplitude above a pre-defined threshold (i.e., 0.227 V/m) was the main factor influencing the responsiveness to tDCS. In the end, the research suggests multiple regression models as useful tool to predict subjects’ responsiveness and to support a personalized approach that tailors the injected current to the morphology of the patient. Full article

Background: Transcranial direct current stimulation (tDCS) and functional electrical stimulation (FES) are established interventions to enhance upper limb motor function (ULMF) in people with stroke (PwS). However, evidence supporting their combined use remains limited and inconsistent. This systematic review aims to evaluate the effectiveness of combined tDCS and FES for improving ULMF, activity, and participation in PwS. Methods: A systematic search was conducted across MEDLINE, CINAHL, SPORTDiscus, CENTRAL, SCOPUS, and Web of Science from inception to December 2024. Randomized and controlled clinical trials (RCTs) involving adults (≥18 years) with acute, subacute, or chronic stroke undergoing combined tDCS and FES interventions were included. Methodological quality was assessed with the PEDro scale, and risk of bias was evaluated using the Cochrane RoB2 tool. A qualitative synthesis was performed employing a five-level evidence grading system. Results: Five RCTs involving 148 participants (mean age range: 50.6–61.2 years; 26% female) were included. Stroke chronicity ranged from 7.6 days to 27.5 months post-onset. Four studies reported significant ULMF improvements with the combined intervention. However, activity and participation outcomes were inconsistently assessed, and results remained inconclusive. Methodological quality varied, with one study rated as excellent, two as good, one as fair, and one as poor. The risk of bias was rated high or with concerns in four out of five studies. Conclusions: Based on qualitative synthesis, moderate-level evidence supports the combined use of tDCS and FES for improving ULMF in PwS. However, high variability in protocols, small sample sizes, and the increased risk of bias in most studies limit the strength of these conclusions. Standardized protocols and larger high-quality RCTs are needed to confirm the effectiveness of this combined intervention. Full article

Background: Transcranial direct current stimulation (tDCS)-induced electric fields (EFs) acting on brain tissues are hardly controllable. Among physical models used in neuroscience research, watermelons are known as head-like phantoms for their dielectric properties. In this study, we aimed to define an inexpensive and reliable method to qualitatively define the spatial distribution of tDCS-induced EFs based on the use of watermelons. Methods: After creating the eight cranial foramina and identifying the location of the 21 EEG scalp electrodes on the peel of a watermelon, voltage differences during stimulation were recorded in each of the 21 scalp electrode positions, one at a time, at four different depths. The recordings were graphically represented by using polar coordinates with the watermelon approximated to a perfect sphere. Results: To validate the model, we performed three experiments in well-known montages. The results obtained were in line with the expected behavior of the EFs. Conclusions: Watermelon might be a cheap and feasible phantom head model to characterize the EFs induced by tDCS and, potentially, even other non-invasive brain stimulation techniques. Full article

Background: Neuroenhancement in sports, through pharmacological and non-pharmacological methods, is a complex and highly debated topic with no definitive regulatory framework established by the World Anti-Doping Agency (WADA). The hypothesis that dermatological changes could serve as observable biomarkers for neurodoping introduces a novel and promising approach to detecting and understanding the physiological impacts of cognitive enhancers in athletes. As neurodoping methods become increasingly sophisticated, developing objective, reliable, and non-invasive detection strategies is imperative. Utilizing dermatological signs as a diagnostic tool for internal neurophysiological changes could offer critical insights into the safety, fairness, and ethical considerations of cognitive enhancement in competitive sports. A systematic correlation between skin manifestations, the timeline of neurodoping practices, and the intensity of cognitive enhancement methods could provide healthcare professionals valuable tools for monitoring athletes’ health and ensuring strict compliance with anti-doping regulations. Methods: Due to the limited body of research on this topic, a systematic review of the literature was conducted, spanning from 2010 to 31 December 2024, using databases such as PubMed, Science Direct, and Google Scholar. This study followed the 2020 PRISMA guidelines and included English-language articles published within the specified period, focusing on skin lesions as adverse reactions to pharmacological and non-pharmacological neuroenhancement methods. The research employed targeted keywords, including “skin lesions AND rivastigmine”, “skin lesions AND galantamine”, “skin lesions AND donepezil”, “skin lesions AND memantine”, and “skin lesions AND transcranial direct electrical stimulation”. Given the scarcity of studies directly addressing neurodoping in sports, the search criteria were broadened to include skin reactions associated with cognitive enhancers and brain stimulation. Eighteen relevant articles were identified and analyzed. Results: The review identified rivastigmine patches as the most used pharmacological method for neuroenhancement, with pruritic (itchy) skin lesions as a frequent adverse effect. Donepezil was associated with fewer and primarily non-pruritic skin reactions. Among non-pharmacological methods, transcranial direct current stimulation (tDCS) was notably linked to skin burns, primarily due to inadequate electrode–skin contact, prolonged exposure, or excessive current intensity. These findings suggest that specific dermatological manifestations could serve as potential indicators of neurodoping practices in athletes. Conclusions: Although specific neuroenhancement methods demonstrate distinctive dermatological side effects that might signal neurodoping, the current lack of robust clinical data involving athletes limits the ability to draw definitive conclusions. Athletes who engage in neurodoping without medical supervision are at an elevated risk of adverse dermatological and systemic reactions. Skin lesions, therefore, could represent a valuable early diagnostic marker for the inappropriate use or overuse of cognitive-enhancing drugs or neuromodulation therapies. The findings emphasize the need for focused clinical research to establish validated dermatological criteria for detecting neurodoping. This research could contribute significantly to the ongoing neuroethical discourse regarding the legitimacy and safety of cognitive enhancement in sports. Full article

Introduction: Neuropsychiatric symptoms such as depression and anxiety are a significant burden on patients with multiple sclerosis (MS). Their pathophysiology is complex and yet to be fully understood. There is an urgent need for non-invasive treatments that directly target the brain and help patients with MS. One such possible treatment is transcranial direct current stimulation (tDCS), a popular and effective non-invasive brain stimulation technique. Methods: This mechanistic review explores the efficacy of tDCS in treating depression and anxiety in MS while focusing on the underlying mechanisms of action. Understanding these mechanisms is crucial, as neuropsychiatric symptoms in MS arise from complex neuroinflammatory and neurodegenerative processes. This review offers insights that may direct more focused and efficient therapeutic approaches by investigating the ways in which tDCS affects inflammation, brain plasticity, and neural connections. Searches were conducted using the PubMed/Medline, ResearchGate, Cochrane, and Google Scholar databases. Results: The literature search yielded 11 studies to be included in this review, with a total of 175 patients participating in the included studies. In most studies, tDCS did not significantly reduce depression or anxiety scores as the studied patients did not have elevated scores indicating depression and anxiety. In the few studies where the patients had scores indicating mild/moderate dysfunction, tDCS was more effective. The risk of bias in the included studies was assessed as moderate. Despite the null or near-null results, tDCS may still prove to be an effective treatment option for depression and anxiety in MS, because tDCS produces a neurobiological effect on the brain and nervous system. To facilitate further work, several possible mechanisms of action of tDCS have been reported, such as the modulation of the frontal–midline theta, reductions in neuroinflammation, the modulation of the HPA axis, and cerebral blood flow regulation. Conclusions: Although tDCS did not overall demonstrate positive effects in reducing depression and anxiety in the studied MS patients, the role of tDCS in this area should not be underestimated. Evidence from other studies indicates the effectiveness of tDCS in reducing depression and anxiety, but the studies included in this review did not include patients with sufficient depression or anxiety. Future studies are needed to confirm the effectiveness of tDCS in neuropsychiatric dysfunctions in MS. Full article