Effects Of Direct Stimulation Research Articles

Electrode positioning errors reduce current dose for focal tDCS set-ups: Evidence from individualized electric field mapping

ObjectiveElectrode positioning errors contribute to variability of transcranial direct current stimulation (tDCS) effects. We investigated the impact of electrode positioning errors on current flow for tDCS set-ups with different focality. MethodsDeviations from planned electrode positions were determined using data acquired in an experimental study (N = 240 datasets) that administered conventional and focal tDCS during magnetic resonance imaging (MRI). Comparison of individualized electric field modeling for planned and empirically derived “actual” electrode positions was conducted to quantify the impact of positioning errors on the electric field dose in target regions for tDCS. ResultsPlanned electrode positions resulted in higher current dose in the target regions for focal compared to conventional montages (7–12%). Deviations from planned positions significantly reduced current flow in the target regions, selectively for focal set-ups (26–30%). Dose reductions were significantly larger for focal compared to conventional set-ups (29–43%). ConclusionsPrecise positioning is crucial when using focal tDCS set-ups to avoid significant reductions of current dose in the intended target regions. SignificanceOur results highlight the urgent need to routinely implement methods for improving electrode positioning, minimization of electrode drift, verification of electrode positions before and/or after tDCS and also to consider positioning errors when investigating dose–response relationships, especially for focal set-ups.

Short-term effects of transcranial direct current stimulation on motor speech in Parkinson’s disease: a pilot study

Introduction: Hypokinetic dysarthria (HD) is a common motor speech symptom of Parkinson’s disease (PD) which does not respond well to PD treatments. We investigated short-term effects of transcranial direct current stimulation (tDCS) on HD in PD using acoustic analysis of speech. Based on our previous studies we focused on stimulation of the right superior temporal gyrus (STG) - an auditory feedback area. Methods: In 14 PD patients with HD, we applied anodal, cathodal and sham tDCS to the right STG using a cross-over design. A protocol consisting of speech tasks was performed prior to and immediately after each stimulation session. Linear mixed models were used for the evaluation of the effects of each stimulation condition on the relative change of acoustic parameters. We also performed a simulation of the mean electric field induced by tDCS. Results: Linear mixed model showed a statistically significant effect of the stimulation condition on the relative change of median duration of silences longer than 50 ms (p = 0.015). The relative change after the anodal stimulation (mean = -5.9) was significantly lower as compared to the relative change after the sham stimulation (mean = 12.8), p = 0.014. We also found a correlation between the mean electric field magnitude in the right STG and improvement of articulation precision after anodal tDCS (R = 0.637; p = 0.019). Conclusions: The exploratory study showed that anodal tDCS applied over the auditory feedback area may lead to shorter pauses in a speech of PD patients.

Enhancement of phonemic verbal fluency in multilingual young adults by transcranial random noise stimulation

Several studies have analyzed the effects of transcranial direct current stimulation on verbal fluency tasks in non-clinical populations. Nevertheless, the reported effects on verbal fluency are inconsistent. In addition, the effect of other techniques such as transcranial random noise stimulation (tRNS) on verbal fluency enhancement has yet to be studied in healthy multilingual populations. This study aims to explore the effects of tRNS on verbal fluency in healthy multilingual individuals. Fifty healthy multilingual (Spanish, English and Basque) adults were randomly assigned to a tRNS or sham group. Electrodes were placed on the left dorsolateral prefrontal cortex and left inferior frontal gyrus. All participants performed phonemic and semantic verbal fluency tasks before, during (online assessment) and immediately after (offline assessment) stimulation in three different languages. The results showed significantly better performance by participants who received tRNS in the phonemic verbal fluency tasks in Spanish (in the online and offline assessment) and English (in the offline assessment). No differences between conditions were found in Basque nor semantic verbal fluency. These findings suggests that tRNS on the left prefrontal cortex could help improve phonemic, yet not semantic, fluency in healthy multilingual adults.

Effect of transcranial direct current stimulation on functional walking capacity in children with cerebral palsy

To investigate the effects of a single session of anodal transcranial direct current stimulation (atDCS) over the primary motor cortex (M1) or left temporal cortex (LTC) during treadmill training (TT) on functional walking capacity in children with cerebral palsy (CP). Seventeen children underwent TT combined with tDCS over M1, tDCS over the LTC and sham stimulation. The Six-Minute Walk Test was performed before, immediately after and 20 minutes after each intervention. TT combined with atDCS over the LTC resulted in a better performance in terms of heart rate, respiratory rate and perception of respiratory and physical effort. TT combined with tDCS over M1 and the LTC achieved similar results for gait speed and distance travelled on the test. Anodal tDCS can be considered a promising intervention for functional walking capacity in children with CP.

OBTAINING OF TiO2-SiO2-P2O5/ZnO COMPOSITES, INVESTIGATION OF THEIR PROPERTIES AND POSSIBILITY OF APPLICATION AS A BIOMATERIAL

In modern implantology composites based on various inorganic and polymeric materials are promising, which are able to provide strong adhesion with tissues in contact with the implanted material and stimulate the growth of new tissue on the implant surface. In the work macroporous cationite Tokem-250 with high selectivity to Zn2+ ions was used as a matrix, which makes it possible to use it in the development of biomaterials. Zinc has a direct stimulating effect on bone tissue formation and has antibacterial properties. For the cationite Tokem-250 based on acryl-divinylbenzene matrix the values of total exchange capacity and sorption capacity in relation to Zn2+ ion were determined. Total exchange capacity of cationite Tokem-250 is 10.35 mmol∙ekv/g, sorption capacity is 73% of the total exchange capacity and is equal to 7.58 mmol∙ekv/g. Spherical composites TiO2-SiO2-P2O5/ZnO on the basis of cationite Tokem-250 were synthesized from alcohol solutions by sol-gel method. For obtaining spherical composite the conditions of heat treatment of samples are established: drying at 60 ºC and step annealing at 150, 250, 350 ºC for 30 min at each temperature step, at 600 ºC - 6 h, at 800 ºC - 1 h. The obtained composites have the ability to precipitate and mineralize calcium-phosphates on their surface in biological media, because they have homogeneous structure with uniform distribution of elements on the surface, mesoporous structure with pore size from 5 to 12 nm and the presence of active centers (Si4+, Ti4+) on the surface of composites. The use of polyvinyl alcohol as a binder does not prevent the formation of an apatite-like layer. For citation: Tkachuk V.A., Lyutova E.S., Buzaev A.A., Borilo L.P., Spivakova L.N. Obtaining of TiO2-SiO2-P2O5/ZnO composites, investigation of their properties and possibility of application as a biomaterial. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 5. P. 70-76. DOI: 10.6060/ivkkt.20246705.6953.

Differential effects of high-definition transcranial direct current stimulation (HD-tDCS) on attentional guidance by working memory in males with substance use disorder according to memory modality

Information stored in working memory can guide perception selection, and this process is modulated by cognitive control. Although previous studies have demonstrated that neurostimulation over the left dorsolateral prefrontal cortex (lDLPFC) contributes to restore cognitive control among individuals with substance use disorder (SUD), there remains an open question about the potential stimulation effects on memory-driven attention. To address this issue, the present study adopted a combined working memory/attention paradigm while employing high-definition transcranial direct current stimulation (HD-tDCS) to stimulate the lDLPFC. Observers were asked to maintain visual or audiovisual information in memory while executing a search task, while the validity of the memory contents for the subsequent search task could be either invalid or neutral. The results showed a faint memory-driven attentional suppression effect in sham stimulation only under the audiovisual condition. Moreover, anodal HD-tDCS facilitated attentional suppression effect in both the strength and temporal dynamics under the visual-only condition, whereas the effect was impaired or unchanged under the audiovisual condition. Surprisingly, cathodal HD-tDCS selectively improved temporal dynamics of the attentional suppression effect under the audiovisual condition. The present study revealed the differential enhancement of HD-tDCS on cognitive control over visual and audiovisual memory-driven attention among individuals with SUD.

Efficacy of transcranial direct current stimulation for controlling of food craving in subjects with overweight or obesity

IntroductionThis study investigates the effects of transcranial direct current stimulation (tDCS) on food craving improvement and changes in brain function associated with craving in overweight and obese subjects.ObjectivesFood craving disregards the homeostatic mechanisms related to appetite and nullifies the rewarding effects of food, directly contributing to body weight and eventually leading to obesity. In this study, we aim to explore the effects of transcranial direct current stimulation (tDCS) on food craving improvement and changes in brain function associated with craving by conducting a total of 10 sessions of tDCS over a period of 2 weeks on overweight and obese subjects.MethodsA total of 86 patients who were overweight or obese (BMI ≥ 23 kg/m2) during the study period were included. The tDCS montage involved placing the anode over the left and the cathode over the right DLPFC. Weight, BMI, neuropsychological variables, and food craving-related variables were assessed. We measured absolute and relative EEG power in 19 channels and analyzed QEEG according to the following frequency ranges: delta (1–4 Hz), theta (4–8 Hz), alpha (8–12 Hz), beta (12–25 Hz), high beta (25–30 Hz), and gamma (30–80 Hz).ResultsAfter the application of tDCS, there was no significant reduction observed in weight and BMI. However, all measures related to food and eating showed a decrease in the intensity of cravings, and there was also a significant reduction in depression, anxiety, and perceived stress. In quantitative EEG analysis, an increase in theta waves was observed in the left frontal area (F7 and F3), an increase in alpha waves in the right parietal area (P4), and a decrease in beta waves in the frontal area (FP2) and occipital area (O1).ConclusionsThis study investigated the effects of tDCS on food craving in overweight and obese individuals, and it was found that there were improvements in psychological factors such as depression and anxiety. Additionally, using quantitative EEG, neurophysiological changes were observed, including an increase in theta waves and a decrease in beta waves.Disclosure of InterestNone Declared

Effect of Transcranial Direct Current Stimulation on Cortical Excitability in Stroke Patients: Review Article

Effect of Transcranial Direct Current Stimulation on Cortical Excitability in Stroke Patients: Review Article

Therapeutic Effect of High-Definition Transcranial Direct Current Stimulation Combined with Suspension Exercise Training on Lower Limb Motor Function of Stroke Patients

Therapeutic Effect of High-Definition Transcranial Direct Current Stimulation Combined with Suspension Exercise Training on Lower Limb Motor Function of Stroke Patients

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

IntroductionPoststroke 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....

Effect of transcranial direct current stimulation on postoperative sleep disturbance in older patients undergoing lower limb major arthroplasty: a prospective, double-blind, pilot, randomised controlled trial

BackgroundPostoperative sleep disturbance (PSD) is a common and serious postoperative complication and is associated with poor postoperative outcomes.AimsThis study aimed to investigate the effect of transcranial direct current stimulation (tDCS)...

Acute effects of transcranial direct current stimulation on cycling performance in trained male athletes

Abstract Objectives The purpose of this study is to examine the effects of applying anodal tDCS (2 mA for 20 min) over the scalp from T3 (anodal-tDCS) to Fp2 (cathodal-tDCS) on the perceptual, physiological and performance responses during maximal incremental and constant-load exercise (CLE) in trained cyclists. Methods Eleven male cyclists performed maximal incremental exercise (MIE) on a cycle ergometer under either tDCS or sham, with power output, heart rate (HR), oxygen uptake (V̇O2), ratings of perceived exertion (RPE) assessed throughout, and blood samples collected before and after MIE. On two separate occasions, nine subjects performed CLE at 62 % of the peak power output followed by a 15 km time trial under either tDCS or sham (n=8 for the time trial). Results HR, V̇O2, RPE and blood samples were collected at regular intervals. There were no differences between tDCS and sham in any variable during the MIE. tDCS elicited a decreased HR (F (4,8)=9.232; p=0.016; η p 2 =0.54), increased V̇O2 (F (4,8)=8.920; p=0.015; η p 2 =0.50) and increased blood non-esterified fatty acids (F (6,8)=11.754; p=0.009; η p 2 =0.60) and glycerol (F (6,8)=6.603; p=0.037; η p 2 =0.49) concentrations during the CLE when compared to sham. tDCS also improved 15 km time trial performance by 3.6 % (p=0.02; d=0.47) without affecting RPE, HR and blood lactate. Conclusions The application of tDCS over the temporal cortex in trained cyclists improved cycling performance during a self-paced time trial but did not enhance performance during maximal incremental exercise. These results are encouraging and merit further investigation of the ergogenic effects of tDCS in trained athletes.

Effects of bi-hemispheric anodal transcranial direct current stimulation on soccer player performance: a triple-blinded, controlled, and randomized study.

The search for increased performance and physical performance are linked to the use of ergogenic resources. The vertical jump is one of the measures commonly used to evaluate the performance of lower limbs in athletes. Transcranial direct current stimulation (tDCS) is a non-invasive, safe, economically viable technique that can modulate cortical excitability, which can influence the increase in the performance of athletes in general. This study aimed to investigate whether the use of tDCS on the primary motor cortex (M1) improves the performance of soccer players. A cross-sectional study was conducted. Twenty-seven players were randomized into three groups: Active tDCS group (n = 9), Sham group (n = 9), and control group (n = 9). Stimulation was applied at 2 mA for 15 min using a cephalic mount. Visual Pain Scale (VAS) and Subjective Recovery Scale (SRS) were monitored before and after tDCS. In addition, the participants performed the Countermovement Jump (CMJ) before and after the stimulation intercalated with Heart Rate (HR) and Rating of Perceived Exertion (RPE CR-10). No differences were found in any of the performance variables analyzed (p > 0.05) nor in the responses of HR (p > 0.05), RPE (p > 0.05), VAS (p > 0.05), and SRS (p > 0.05) between groups. The tDCS in M1 did not change the performance of the vertical jump, and there was no improvement in the subjective scales. New studies should also be developed with different stimulus intensities in different cortical areas and sports modalities.

Comparing the effects of cerebellar and prefrontal anodal transcranial direct current stimulation concurrent with postural training on balance and fatigue in patients with multiple sclerosis: a double-blind, randomized, sham-controlled trial.

Fatigue and balance disorders are common challenges experienced by Multiple Sclerosis (MS) individuals. The purpose of this study was to compare the concurrent effects of cerebellar and prefrontal anodal trans-cranial direct current stimulation (a-tDCS) with postural training on balance and fatigue in MS patients. 51 patients were evaluated to randomly allocation to a-tDCS over cerebellum, a-tDCS over dorsolateral prefrontal cortex (DLPFC) and sham group. 46 individuals (n = 16 in experimental groups and n = 14 in control group) followed treatment. All the groups received 10 sessions of postural training. The experimental groups underwent a-tDCS with a current of 1.5mA for a period of 20min. While, in the sham group, tDCS was only activated for 30s and then turned off. The treatment included 10 sessions for four weeks. Before and after intervention, fatigue and balance were assessed using Fatigue Severity Scale (FSS), Timed Up and Go (TUG) test and Berg Balance Score (BBS), respectively. There was found a significant reduction in fatigue in the group receiving a-tDCS over the prefrontal cortex with postural training compared to the other two groups (P < 0.001). Additionally, a significant improvement was found in balance in the group receiving a-tDCS over the cerebellum concurrent with postural training in comparison to the other two groups (P < 0.001). Besides, in the sham group, the significant results were not reported in the variables. (P > 0.001). The results demonstrated that a-tDCS enhances the effects of postural training on balance and fatigue in MS patients.

Noninvasive neuromodulatory effect on cognition in individuals with traumatic brain injury: A single-blinded, two-arm parallel randomized clinical trial.

The study aimed to compare the effect of cranial electrical stimulation (CES) and transcranial direct current stimulation (tDCS) in improving cognition among individuals with mild traumatic brain injury. The pretest-posttest randomized controlled study was conducted between November 2020 and March 2022. Seventy-two patients (64 males, 8 females; mean age: 40.5±9.5 years; range, 18 to 45 years) experiencing cognitive impairment within three months of traumatic brain injury were recruited. Participants were randomly assigned into two groups: Group 1 (CES with cognitive training, n=36) and Group 2 (tDCS with cognitive training, n=36). Participants were blinded in the study. Both groups received 30-min sessions of neuromodulation along with 30 min of cognitive training five days a week for four weeks. The patients were assessed at baseline and at the end of two and four weeks of intervention. The primary outcome measure was the Montreal Cognition Assessment (MoCA), and the secondary outcome measure was the Galveston Orientation Amnesia Test (GOAT). Demographic and baseline characteristics depicted normal distribution for both groups (p>0.05). Within group analyses of both groups demonstrated significant differences for both outcome measures (MoCA: p=0.001; GOAT: p=0.001). Between group analyses of MoCA showed significant improvement with p-value of 0.001 while GOAT exhibited p-value of 0.002 showing significant difference between the two groups. Time group interaction effect and covariance analyses depicted significant improvement with p-value of 0.001 for both outcome measures with excellent effect size >0.80. Cranial electrical stimulation was a more effective noninvasive neuromodulatory device than tDCS in improving cognition among individuals with traumatic brain injury.

Effects of sham transcranial direct current stimulation (tDCS) on visual-spatial learning: A combined behavioral and fMRI approach

Effects of sham transcranial direct current stimulation (tDCS) on visual-spatial learning: A combined behavioral and fMRI approach

TDCS for parkinson‘s disease disease-related pain: A randomized trial

ObjectiveTo evaluate the effects of transcranial direct current stimulation (tDCS) on Parkinson’s disease (PD)-related pain. MethodsThis triple-blind randomized controlled trial included twenty-two patients (age range 38–85, 10 male) with PD-related pain. Eleven subjects received ten sessions of 20 minutes tDCS over the primary motor cortex contralateral to pain at 2 mA intensity. Eleven subjects received sham stimulation. Outcome measures included changes in the Kinǵs Parkinsońs Pain Scale (KPPS), Brief Pain Inventory (BPI), widespread mechanical hyperalgesia (WMH), temporal summation of pain (TS), and conditioned pain modulation (CPM). ResultsSignificant differences were found in KPPS between groups favoring the active-tDCS group compared to the sham-tDCS group at 15-days follow-up (p = 0.014) but not at 2 days post-intervention (p = 0.059). The active-group showed significant improvements over the sham-group after 15 days (p = 0.017). Significant changes were found in CPM between groups in favor of active-tDCS group at 2 days post-intervention (p = 0.002) and at 15 days (p = 0.017). No meaningful differences were observed in BPI or TS. ConclusionstDCS of the primary motor cortex alleviates perceived PD-related pain, reduces pain sensitization, and enhances descending pain inhibition. SignificanceThis is the first study to test and demonstrate the use of tDCS for improving PD-related pain.

Effect of high-definition transcranial direct current stimulation among late-subacute and chronic stroke survivors with fatigue: A randomized-controlled crossover trial protocol

Post-stroke fatigue (PSF) is a commonly overlooked symptom that impacts daily functioning and quality of life. It is caused by altered functional connectivity within the brain networks, which can potentially be influenced by neuromodulation. Multiple cortical regions have been targeted to reduce PSF, but the most efficient ones remain uncertain. Therefore, we aim to identify the most appropriate cortical stimulation site to reduce PSF. Twenty participants with PSF will be included in this cross-over trial. Each participant will receive one session of active anodal high definition- transcranial direct current stimulation (HD-tDCS) over three different cortical areas and one session of sham tDCS in a cross-over manner, with a two-week of washout period in between. Pre- and post- fatigue will be assessed using Fatigue Severity Scale and fatigability using electromyography by determining the time to task failure. Resting-state electroencephalography will be performed before and after each stimulation session to determine the functional connectivity of the cortical areas stimulated.

Exploring the Differential Effects of Transcranial Direct Current Stimulation: A Comparative Analysis of Motor Cortex and Cerebellar Stimulation

BackgroundTranscranial Direct Current Stimulation (tDCS) is a non-invasive brain stimulation technique. Constant electric current is passed through the patient's scalp with the aim of modulating cortical excitability. Stroke is a cerebrovascular disease characterized by hemorrhage or cerebral ischemia. This systematic review and meta-analysis are aimed at comparing the efficacy of motor cortex stimulation with that of cerebellar stimulation by using transcranial direct current stimulation. MethodGoogle Scholar, PubMed, EMBASE, Cochrane CENTRAL, and Physiotherapy Evidence Database (Pedro) databases were searched for studies. The extracted qualitative data was synthesized systematically. Cochrane RevMan software was used to conduct a meta-analysis of quantitative data. The fixed effects mean difference of the collected data was calculated at a 95% confidence interval (CI) for the changes in balance and side effects. ResultsThis research included 10 articles with seven studies assessing changes in balance (outcome measured in CoP and FMA scores) and side effects (tingling and itching were the most prevalent). There was no significant difference between the efficacy levels of m1-tDCS versus ctDCS (P = 0.18), m1-tDCS versus sham (P = 0.92), and ctDCS versus sham (P = 0.19). Itching and tingling sensation were the most common and were significantly prevalent in sham interventions (P < 0.00001). ConclusionWe found that motor cortex and cerebellar stimulations are both effective in improving motor function in stroke patients. There are no adverse effects to using the interventions besides mild itching and tingling experienced during the stimulation.

The effect of transcranial direct current stimulation (tDCS) on cognitive function recovery in patients with depression following electroconvulsive therapy (ECT): protocol for a randomized controlled trial

BackgroundElectroconvulsive therapy (ECT) is a highly effective treatment for depressive disorder. However, the use of ECT is limited by its cognitive side effects (CSEs), and no specific intervention has been developed to address this problem. As transcranial direct current stimulation (tDCS) is a safe and useful tool for improving cognitive function, the main objective of this study was to explore the ability to use tDCS after ECT to ameliorate the cognitive side effects.Methods60 eligible participants will be recruited within two days after completing ECT course and randomly assigned to receive either active or sham stimulation in a blinded, parallel-design trial and continue their usual pharmacotherapy. The tDCS protocol consists of 30-min sessions at 2 mA, 5 times per week for 2 consecutive weeks, applied through 15-cm2 electrodes. An anode will be placed over the left dorsolateral prefrontal cortex (DLPFC), and a cathode will be placed over the right supraorbital cortex. Cognitive function and depressive symptoms will be assessed before the first stimulation (T0), after the final stimulation (T1), 2 weeks after the final stimulation (T2), and 4 weeks after the final stimulation (T3) using the Cambridge Neuropsychological Test Automated Battery (CANTAB).DiscussionWe describe a novel clinical trial to explore whether the administration of tDCS after completing ECT course can accelerates recovery from the CSEs. We hypothesized that the active group would recover faster from the CSEs and be superior to the sham group. If our hypothesis is supported, the use of tDCS could benefit eligible patients who are reluctant to receive ECT and reduce the risk of self-inflicted or suicide due to delays in treatment.Trial registration detailsThe trial protocol is registered with https://www.chictr.org.cn/ under protocol registration number ChiCTR2300071147 (date of registration: 05.06.2023). Recruitment will start in November 2023.