Sessions Of Transcranial Direct Current Stimulation Research Articles

Effect of transcranial direct current stimulation in the initial weeks post-stroke: a pilot randomized study.

This study aimed at assessing the alterations in upper limb motor impairment and connectivity between motor areas following the post-stroke delivery of cathodal transcranial direct current stimulation sessions. Modifications in the Fugl-Meyer Assessment scores, connectivity between the primary motor cortex of the unaffected and affected hemispheres, and between the primary motor and premotor cortices of the unaffected hemisphere were compared prior to and following six sessions of cathodal transcranial direct current stimulation application in 13 patients (active = 6; sham = 7); this modality targets the primary motor cortex of the unaffected hemisphere early after a stroke. Clinically relevant distinctions in Fugl-Meyer Assessment scores (≥9 points) were observed more frequently in the Sham Group than in the Active Group. Between-group differences in the alterations in Fugl-Meyer Assessment scores were not statistically significant (Mann-Whitney test, p=0.133). ROI-to-ROI correlations between the primary motor cortices of the affected and unaffected hemispheres post-therapeutically increased in 5/6 and 2/7 participants in the Active and Sham Groups, respectively. Between-group differences in modifications in connectivity between the aforementioned areas were not statistically significant. Motor performance enhancements were more frequent in the Sham Group compared to the Active Group. The results of this hypothesis-generating investigation suggest that heightened connectivity may not translate into early clinical benefits following a stroke and will be crucial in designing larger cohort studies to explore mechanisms underlying the impacts of this intervention. ClinicalTrials.gov Identifier: NCT02455427.

Effects of Transcranial Direct-Current Stimulation (tDCS) Treatment Sessions on Neuropsychological ‎Functioning Among Detoxified Inpatients with Alcohol Dependence: A Randomized Sham-Controlled Clinical Trial

ABSTRACT Individuals with alcohol dependence often experience cognitive dysfunction after detoxification, which can persist even after sustained abstinence. Transcranial direct current stimulation (tDCS) has shown promise in improving cognitive functioning in these patients. The main objective of this research was to assess the impact of ten sessions of transcranial direct-current stimulation (tDCS) targeting the dorsolateral prefrontal cortex (DLPFC) on the neuropsychological functioning of hospitalized individuals with alcohol dependence who have undergone detoxification. This single-center, parallel, and single-blind randomized controlled trial assessed the effects of ten sessions of add-on tDCS treatment on neuropsychological functions. 44 recently detoxified alcohol-dependent inpatients were randomly assigned to either treatment as usual (TAU) plus ten sessions of active tDCS over left DLPFC, or TAU plus ten sessions of sham tDCS and assessed the effect of tDCS sessions and time on neuropsychological functions. Neuropsychological functions were evaluated in inpatients undergoing treatment for alcohol dependence at T1 (9.95 + 2.42 days abstinence) and T2 (19 ± 1.48 days abstinence), and while time had a significant impact on mean scores of various neuropsychological tests, neither active tDCS treatment nor its interaction with time displayed a significant effect on neuropsychological functioning, as revealed by two-way ANOVAs with repeated measurements. In detoxified inpatients with alcohol dependence, tDCS treatment was not found to have a significant impact on neuropsychological functioning when compared to sham treatment, whereas abstinence from alcohol for approximately three weeks resulted in significant improvements in various cognitive domains including mental speed, verbal learning & memory, visual memory, verbal fluency, and response inhibition.

Effect of Single Session of Anodal M1 Transcranial Direct Current Stimulation-TDCS-On Cortical Hemodynamic Activity: A Pilot Study in Fibromyalgia.

Transcranial direct current stimulation (TDCS) on the primary motor cortex (M1) has been reported to be effective in fibromyalgia (FM). Our previous works have shown hypometabolism of motor networks in FM using Functional Near Infrared Spectroscopy (fNIRS), which could contribute to pain symptoms. To investigate if a single Transcranial Direct Current Stimulation (TDCS) session can restore the reduced metabolism expected in FM patients, we compared metabolic activity in FM patients and controls during a finger-tapping task in basal condition, sham condition, and under anodal TDCS on M1. During the finger tapping task, a continuous wave 20 channel fNIRS system was placed across the bilateral central-frontal areas in 22 healthy controls and 54 FM patients. Subjects were randomly assigned to real TDCS or sham stimulation. The finger-tapping slowness did not change after real and sham stimulation. After real TDCS stimulation, FM patients showed an increased activation of cortical motor regions (t-statistic = -2.5246, p-value = 0.0125 for the stimulated hemisphere and t-statistic = -4.6638, p-value = 0.0001 for the non-stimulated hemisphere). The basal differences between FM and controls reverted after real TDCS, while this effect was not observed for sham stimulation. A single TDCS session of the cortical motor network seemed able to restore basic cortical hypometabolism in FM patients. Further studies could clarify the long-term effect of M1 stimulation on cortical metabolism, and its relevance in pain processing and clinical features.

Management of Chronic Pain and PTSD in Veterans With tDCS+Prolonged Exposure: A Pilot Study

Chronic pain and posttraumatic stress disorder (PTSD) are prevalent comorbid conditions, particularly in Veterans; however, there are few integrated treatments for chronic pain and PTSD. Instead, interventions are typically implemented separately and may involve addictive opioids. Although there are highly effective, non-pharmacological treatments for PTSD, they are plagued by high dropout, which may be exacerbated by comorbid pain, as these PTSD treatments typically require increased activity. Importantly, a noninvasive pain treatment, tDCS (transcranial direct current stimulation) shows indications of effectiveness and may be integrated with psychological treatments, even when delivered via telehealth. This study examines the feasibility and initial efficacy of integrating home telehealth tDCS with prolonged exposure (PE), an evidence-based PTSD treatment. Thirty-nine Veterans were contacted, 31 consented to evaluation, 21 were enrolled, and 16 completed treatment and provided pre- and post-treatment data at one of two Veterans Affairs Medical Centers. Transcranial direct current stimulation sessions corresponded with PE exposure assignments, as there is theoretical reason to believe that tDCS may potentiate extinction learning featured in PE. Patients evinced significant improvement in both pain interference and PTSD symptoms and a trend toward improvement in depression symptoms. However, a significant change in pain intensity was not observed, likely because of the small sample size. The findings provide initial support for the feasibility of an entirely home-based, integrated treatment for comorbid PTSD and pain.

Evaluation of the immediate effects of a single transcranial direct current stimulation session on astrocyte activation, inflammatory response, and pain threshold in naïve rats

Transcranial direct current stimulation (tDCS) has demonstrated clinical benefits such as analgesia, anti-inflammatory, and neuroprotective effects. However, the mechanisms of action of a single tDCS session are poorly characterized. The present study aimed to evaluate the effects of a single tDCS session on pain sensitivity, inflammatory parameters, and astrocyte activity in naive rats. In the first experiment, sixty-day-old male Wistar rats (n = 95) were tested for mechanical pain threshold (von Frey test). Afterward, animals were submitted to a single bimodal tDCS (0.5 mA, 20 min) or sham-tDCS session. According to the group, animals were re-tested at different time intervals (30, 60, 120 min, or 24 h) after the intervention, euthanized, and the cerebral cortex collected for biochemical analysis. A second experiment (n = 16) was performed using a similar protocol to test the hypotheses that S100B levels in the cerebrospinal fluid (CSF) are altered by tDCS. Elisa assay quantified the levels of tumor necrosis factor–alfa (TNF-α), interleukin-10 (IL10), S100 calcium-binding protein B (S100B), and Glial fibrillary acidic protein (GFAP). Data were analyzed using ANOVA and independent t-test (P < 0.05). Results showed that tDCS decreased pain sensitivity (30 and 60 min), cerebral TNF-α and S100B levels (30 min). CSF S100B levels increased 30 min after intervention. There were no differences in IL10 and GFAP levels. TCDS showed analgesic, anti-inflammatory, and neuroprotective effects in naive animals. Therefore, this non-invasive and inexpensive therapy may potentially be a preemptive alternative to reduce pain, inflammation, and neurodegeneration in situations where patients will undergo medical procedures (e.g., surgery).

Evaluation of the effect of transcranial direct current stimulation on language impairments in the behavioural variant of frontotemporal dementia

The behavioural variant of frontotemporal dementia is a neurodegenerative disease characterized by bilateral atrophy of the prefrontal cortex, gradual deterioration of behavioural and executive capacities, a breakdown of language initiation and impaired search mechanisms in the lexicon. To date, only a few studies have analysed the modulation of language deficits in the behavioural variant of frontotemporal dementia patients with transcranial direct current stimulation, yet with inconsistent results. Our goal was to assess the impact on language performance of a single session of transcranial direct current stimulation on patients with the behavioural variant of frontotemporal dementia. Using a sham-controlled double-blind crossover design in a cohort of behavioural frontotemporal dementia patients (n = 12), we explored the impact on language performance of a single transcranial direct current stimulation session delivering anodal or cathodal transcranial direct current stimulation, over the left and right dorsolateral prefrontal cortex, compared with sham stimulation. A Letter fluency and a Picture naming task were performed prior and following transcranial direct current stimulation, to assess modulatory effects on language. Behavioural frontotemporal dementia patients were impaired in all evaluation tasks at baseline compared with healthy controls. Computational finite element method (FEM) models of cortical field distribution corroborated expected impacts of left-anodal and right-cathodal transcranial direct current stimulation over the dorsolateral prefrontal cortex and showed lower radial field strength in case of atrophy. However, none of the two tasks showed statistically significant evidence of language improvement caused by active transcranial direct current stimulation compared with sham. Our findings do not argue in favour of pre-therapeutic effects and suggest that stimulation strategies evaluating the modulatory role of transcranial direct current stimulation in the behavioural variant of frontotemporal dementia must carefully weigh the influence of symptom severity and cortical atrophy affecting prefrontal regions to ensure clinical success.

The Effects of a Single Transcranial Direct Current Stimulation Session on Impulsivity and Risk Among a Sample of Adult Recreational Cannabis Users.

Individuals with substance use disorders exhibit risk-taking behaviors, potentially leading to negative consequences and difficulty maintaining recovery. Non-invasive brain stimulation techniques such as transcranial direct current stimulation (tDCS) have yielded mixed effects on risk-taking among healthy controls. Given the importance of risk-taking behaviors among substance-using samples, this study aimed to examine the effects of tDCS on risk-taking among a sample of adults using cannabis. Using a double-blind design, 27 cannabis users [M(SD) age = 32.48 (1.99), 41% female] were randomized, receiving one session of active or sham tDCS over the bilateral dorsolateral prefrontal cortex (dlPFC). Stimulation parameters closely followed prior studies with anodal right dlPFC and cathodal left dlPFC stimulation. Risk-taking—assessed via a modified Cambridge Gambling Task—was measured before and during tDCS. Delay and probability discounting tasks were assessed before and after stimulation. No significant effects of stimulation on risk-taking behavior were found. However, participants chose the less risky option ∼86% of the trials before stimulation which potentially contributed to ceiling effects. These results contradict one prior study showing increased risk-taking among cannabis users following tDCS. There was a significant increase in delay discounting of a $1000 delayed reward during stimulation for the sham group only, but no significant effects for probability discounting. The current study adds to conflicting and inconclusive literature on tDCS and cognition among substance-using samples. In conclusion, results suggest the ineffectiveness of single session dlPFC tDCS using an established stimulation protocol on risk-taking, although ceiling effects at baseline may have also prevented behavior change following tDCS.

No evidence for any effect of multiple sessions of frontal transcranial direct stimulation on mood in healthy older adults

The dorsolateral prefrontal cortex (DLPFC) is part of a network important for emotional regulation and the possibility of modulating activity in this region with transcranial direct current stimulation (TDCS) to change mood has gained great interest, particularly for application in clinical populations. Whilst results in major depressive disorder have been promising, less is known about the effects of TDCS on mood in non-clinical populations. We hypothesized that multiple sessions of anodal TDCS applied over the left DLPFC would enhance mood, primarily as measured by the Profile of Mood States questionnaire, in healthy older adults. In addition, in an exploratory analysis, we examined the potentially moderating role of working memory training. Working memory, just like emotional regulation, taxes the DLPFC, which suggests that engaging in a working memory task whilst receiving TDCS may have a different effect on activity in this region and consequently mood. A total of 123 participants between 65 and 75 years of age were randomly assigned to receive either 20 sessions of TDCS, with or without working memory training, or 20 sessions sham stimulation, with or without working memory training. We found no support for enhancement of mood due to TDCS in healthy older adults, with or without cognitive training and conclude that the TDCS protocol used is unlikely to improve mood in non-depressed older individuals.

Safety and effects on motor cortex excitability of five anodal transcranial direct current stimulation sessions in 24 hours

Application parameters of transcranial direct current stimulation (tDCS) for therapeutic purposes are relatively restricted. The aim of this study was to assess safety and effects on motor cortex excitability of an intensive anodal-tDCS protocol. In 26 healthy subjects, five 15-minute anodal-tDCS sessions were delivered, at increasing time intervals, over 24hours. Safety was defined as absence of serious adverse events including brain tissue alterations on magnetic resonance imaging. Effect on motor cortex excitability was evaluated by motor evoked potential (MEP) amplitude, measured eight times. No serious adverse events occurred. Mild adverse events, such as reversible scalp erythema or transient metallic taste, were observed in 27% of subjects. MEP amplitudes did not change in any of the recording periods. When inter-individual variability was taken into account and threshold values defined, 50% of subjects were classified as responders, 15% were inverse responders, and 35% non-responders. In the responders, normalized MEP was increased by 57% 1hour after the first anodal-tDCS and increased by 50% three hours after two stimulations delivered 1hour apart. Intra-individual, inter-sessional consistency of MEP response over four measurements was 61-77%. Five anodal-tDCS delivered in 24hours are safe and well tolerated, expanding the safety standard of tDCS. However, only half of subjects respond to anodal-tDCS with a robust and durable MEP augmentation. On the other hand, the response to a single anodal-tDCS predicts fairly well the response to other sessions in the same subject. These findings should be considered in clinical trials utilizing repeated anodal-tDCS.

The Effects of Acute Multisession Bifrontal Transcranial Direct Current Stimulation on Intractable Tinnitus and comorbid depression and anxiety: A Study Protocol for Randomized Controlled Trial

Background and Objective: Transcranial Direct Current Stimulation (tDCS) may exert therapeutic effects on tinnitus. This Randomized Control Trial (RCT) with double blind and placebo design investigates the potential therapeutic effects of Transcranial Direct Current Stimulation on chronic and intractable tinnitus using a new protocol. Acute repeated sessions of bifrontal Transcranial Direct Current Stimulation with two months follow up will be used for treatment of tinnitus symptoms and comorbid anxiety and depression. To best of our knowledge, this is the first randomized control trial investigating the effects of acute Transcranial Direct Current Stimulation exposure in intractable tinnitus. Methods: This randomized control trial is conducted as double blinded placebo controlled with parallel group in patients with chronic intractable tinnitus. The patients will be randomly divided into two real or intervention and sham or placebo Transcranial Direct Current Stimulation. The real Transcranial Direct Current Stimulation group will receive two sessions per day with intersession interval of 6 hours for 5 consecutive days per week for one week (total 10 sessions). The Transcranial Direct Current Stimulation parameters include bifrontal (anode/cathode over right/left dorsolateral prefrontal cortex (DLPFC) 2 mA current (current density 57.1 μA/cm2), each session 20 min through 35 cm2 electrodes. The sham group will receive the same Transcranial Direct Current Stimulation parameters and electrode montage and after 30 seconds, the device will be turned off without informing the patient. The primary outcome is the score of Tinnitus Handicap Inventory (THI) measured at baseline (pre-intervention) and post-intervention at immediately, one, and two months after last session. The secondary outcomes are tinnitus loudness, tinnitus distress, depression, and anxiety scores. The tinnitus loudness and distress are measured with a 0-10 Numerical Rating Scale (NRS) preintervention and post-intervention at immediately, one hour, one week, one, and two months after the last Transcranial Direct Current Stimulation session. Beck Depression (BDI-II) and Anxiety Inventories (BAI) is respectively used for measuring depression and anxiety score pre- and post-intervention. Finally, the adverse effects of and tolerability to Transcranial Direct Current Stimulation will be assessed in both real and sham groups using customized questionnaire. Discussion: To the best of our knowledge this is the first RCT investigating the effects of daily two sessions of Transcranial Direct Current Stimulation in repeated regime on chronic intractable tinnitus symptoms, depression, anxiety, and adverse effects in a long term study of two months follow-up.

Safety and effects on motor cortex excitability of five cathodal transcranial direct current stimulation sessions in 25 hours

To assess the safety and effects on motor cortex excitability of five cathodal-tDCS sessions (charge density 342.9C/m2) delivered over the dominant motor cortex with a return electrode over the ipsilateral shoulder at increasing time intervals in 25hours. Safety was operatively defined as absence of serious adverse events related to tDCS including brain tissue alterations documentable by magnetic resonance imaging and spectroscopy. Effects on motor cortex excitability were evaluated by motor evoked potential (MEP) amplitude. Thirty-two healthy subjects were enrolled. No serious adverse events occurred. Magnetic resonance imaging and spectroscopy did not show alterations. Inter-individual MEP variability was assessed by the standard error of mean at baseline and subjects were classified on the basis of the ratio between normalized MEPs after the first stimulation compared to baseline. Fifty-six percent of subjects responded with reduction of MEP amplitude, 25% were non-responders and 19% were inverse responders. In responders, MEP suppression was 32% one hour after the end of first cathodal-tDCS, 21% three hours after the second, no longer present with increasing stimulation intervals and 38% two and half hours after the fifth stimulation. Intra-individual inter-sessional reliability in response was high (88-92%). Five cathodal-tDCS sessions in 25hours are safe. Inter-individual variability in MEP suppression is considerable but response to one cathodal-tDCS highly predicts the response to other sessions. Duration of MEP suppression is limited to three hours. These findings should be considered in trials utilizing repeated cathodal-tDCS.

Effect of a single session of transcranial direct-current stimulation combined with virtual reality training on the balance of children with cerebral palsy: a randomized, controlled, double-blind trial.

[Purpose] The aim of the present study was to investigate the effects of a single session of transcranial direct current stimulation combined with virtual reality training on the balance of children with cerebral palsy. [Subjetcs and Methods] Children with cerebral palsy between four and 12 years of age were randomly allocated to two groups: an experimental group which performed a single session of mobility training with virtual reality combined with active transcranial direct current stimulation; and a control group which performed a single session of mobility training with virtual reality combined with placebo transcranial direct current stimulation. The children were evaluated before and after the training protocols. Static balance (sway area, displacement, velocity and frequency of oscillations of the center of pressure on the anteroposterior and mediolateral axes) was evaluated using a force plate under four conditions (30-second measurements for each condition): feet on the force plate with the eyes open, and with the eyes closed; feet on a foam mat with the eyes open, and with the eyes closed. [Results] An increase in sway velocity was the only significant difference found. [Conclusion] A single session of anodal transcranial direct current stimulation combined with mobility training elicited to lead to an increase in the body sway velocity of children with cerebral palsy.

Combining physical training with transcranial direct current stimulation to improve gait in Parkinson’s disease: a pilot randomized controlled study

Objective: To improve gait and balance in patients with Parkinson’s disease by combining anodal transcranial direct current stimulation with physical training. Design: In a double-blind design, one group (physical training; n = 8) underwent gait and balance training during transcranial direct current stimulation (tDCS; real/sham). Real stimulation consisted of 15 minutes of 2 mA transcranial direct current stimulation over primary motor and premotor cortex. For sham, the current was switched off after 30 seconds. Patients received the opposite stimulation (sham/real) with physical training one week later; the second group (No physical training; n = 8) received stimulation (real/sham) but no training, and also repeated a sequential transcranial direct current stimulation session one week later (sham/real). Setting: Hospital Srio Libanes, Buenos Aires, Argentina. Subjects: Sixteen community-dwelling patients with Parkinson’s disease. Interventions: Transcranial direct current stimulation with and without concomitant physical training. Main measures: Gait velocity (primary gait outcome), stride length, timed 6-minute walk test, Timed Up and Go Test (secondary outcomes), and performance on the pull test (primary balance outcome). Results: Transcranial direct current stimulation with physical training increased gait velocity (mean = 29.5%, SD = 13; p < 0.01) and improved balance (pull test: mean = 50.9%, SD = 37; p = 0.01) compared with transcranial direct current stimulation alone. There was no isolated benefit of transcranial direct current stimulation alone. Although physical training improved gait velocity (mean = 15.5%, SD = 12.3; p = 0.03), these effects were comparatively less than with combined tDCS + physical therapy (p < 0.025). Greater stimulation-related improvements were seen in patients with more advanced disease. Conclusions: Anodal transcranial direct current stimulation during physical training improves gait and balance in patients with Parkinson’s disease. Power calculations revealed that 14 patients per treatment arm (α = 0.05; power = 0.8) are required for a definitive trial.

Effect of a single session of transcranial direct-current stimulation on balance and spatiotemporal gait variables in children with cerebral palsy: A randomized sham-controlled study.

Background: Transcranial direct-current stimulation (tDCS) has been widely studied with the aim of enhancing local synaptic efficacy and modulating the electrical activity of the cortex in patients with neurological disorders. Objective: The purpose of the present study was to determine the effect of a single session of tDCS regarding immediate changes in spatiotemporal gait and oscillations of the center of pressure (30 seconds) in children with cerebral palsy (CP). Method:A randomized controlled trial with a blinded evaluator was conducted involving 20 children with CP between six and ten years of age. Gait and balance were evaluated three times: Evaluation 1 (before the stimulation), Evaluation 2 (immediately after stimulation), and Evaluation 3 (20 minutes after the stimulation). The protocol consisted of a 20-minute session of tDCS applied to the primary motor cortex at an intensity of 1 mA. The participants were randomly allocated to two groups: experimental group - anodal stimulation of the primary motor cortex; and control group - placebo transcranial stimulation. Results: Significant reductions were found in the experimental group regarding oscillations during standing in the anteroposterior and mediolateral directions with eyes open and eyes closed in comparison with the control group (p<0.05). In the intra-group analysis, the experimental group exhibited significant improvements in gait velocity, cadence, and oscillation in the center of pressure during standing (p<0.05). No significant differences were found in the control group among the different evaluations. Conclusion: A single session of tDCS applied to the primary motor cortex promotes positive changes in static balance and gait velocity in children with cerebral palsy.

Multiple sessions of transcranial direct current stimulation to the intact hemisphere improves visual function after unilateral ablation of visual cortex

Damage to cerebral systems is frequently followed by the emergence of compensatory mechanisms, which serve to reduce the effects of brain damage and allow recovery of function. Intrinsic recovery, however, is rarely complete. Non-invasive brain stimulation technologies have the potential to actively shape neural circuits and enhance recovery from brain damage. In this study, a stable deficit for detecting and orienting to visual stimuli presented in the contralesional visual hemifield was generated by producing unilateral brain damage of the right posterior parietal and contiguous visual cortical areas. A long regimen of inhibitory non-invasive transcranial direct-current stimulation (cathodal tDCS, 2mA, 20min) was applied to the contralateral (intact) posterior parietal cortex over 14weeks (total of 70 sessions, one per day, 5days per week) and behavioral outcomes were periodically assessed. In three out of four stimulated cats, lasting recovery of visuospatial function was observed. Recovery started after 2-3weeks of stimulation, and recovered targets were located first in the periphery, and moved to more central visual field locations with the accrual of stimulation sessions. Recovery for moving tasks followed a biphasic pattern before reaching plateau levels. Recovery did not occur for more difficult visual tasks. These findings highlight the ability of multiple sessions of transcranial direct-current stimulation to produce recovery of visuospatial function after unilateral brain damage.

Transcranial direct-current stimulation induced in stroke patients with aphasia: a prospective experimental cohort study.

Previous animal and human studies have shown that transcranial direct current stimulation can induce significant and lasting neuroplasticity and may improve language recovery in patients with aphasia. The objective of the study was to describe a cohort of patients with aphasia after stroke who were treated with transcranial direct current stimulation. Prospective cohort study developed in a public university hospital. Nineteen patients with chronic aphasia received 10 transcranial direct current stimulation sessions lasting 20 minutes each on consecutive days, using a current of 2 mA. The anode was positioned over the supraorbital area and the cathode over the contralateral motor cortex. The following variables were analyzed before and after the 10 neuromodulation sessions: oral language comprehension, copying, dictation, reading, writing, naming and verbal fluency. There were no adverse effects in the study. We found statistically significant differences from before to after stimulation in relation to simple sentence comprehension (P = 0.034), naming (P = 0.041) and verbal fluency for names of animals (P = 0.038). Improved scores for performing these three tasks were seen after stimulation. We observed that excitability of the primary motor cortex through transcranial direct current stimulation was associated with effects on different aspects of language. This can contribute towards future testing in randomized controlled trials.

Transcranial direct current stimulation of the affected hemisphere does not accelerate recovery of acute stroke patients

Transcranial direct current stimulation (TDCS) is a potential tool to improve motor deficits in chronic stroke patients. Safety and efficacy of this procedure in acute stroke patients have not yet been addressed. We performed in our stroke unit a single-centre randomized, double-blind, sham-controlled study to investigate safety and efficacy of anodal TDCS of the affected hemisphere in acute stroke patients. The second day from stroke onset, 50 acute stroke patients received either five-daily sessions of anodal (n=25) at 2mA for 20min or sham TDCS (n=25) to the ipsilesional primary motor cortex (M1). Motor deficit was assessed by the short form of the Fugl-Meyer motor scale (FM) and overall neurological deficit by the National Institute of Health Stroke Scale (NIHSS) at onset, at 5days after stroke and after 3months. No side effects were detected during either TDCS or sham. In both groups, there was a significant improvement in NIHSS and FM scores, which did not significantly differ when comparing TDCS and sham. Five-daily sessions of anodal TDCS to the ipsilesional M1 appear to be safe in acute stroke patients but do not improve clinical outcome.

Enhancing the Working Memory of Stroke Patients Using tDCS

We investigated whether anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex affected the working memory performance of patients after a stroke. Ten patients (mean age 47.7 yrs) with cognitive deficits after a first-ever stroke participated in this single-blind, crossover, and sham-controlled experiment. Each patient was randomly assigned to undergo two transcranial direct current stimulation sessions: anodal dorsolateral prefrontal cortex and sham stimulation within 48 hrs of a washout period. All participants performed a two-back working memory task before and after the administration of the transcranial direct current stimulation. Accuracy (correction rate), recognition accuracy (correction rate-commission error rate), and response time were measured during each experiment. Repeated-measures analysis of variance indicated a significant interaction effect of transcranial direct current stimulation type and time on the recognition accuracy. Post hoc analyses revealed a significant difference between prestimulation and poststimulation in the anodal stimulation group but not in the sham stimulation group. Regarding the accuracy, the paired t test indicated significant improvement only after anodal transcranial direct current stimulation without a significant interaction effect between the two transcranial direct current stimulation types. The response time was not significantly different in the anodal and sham stimulation groups. Our results demonstrated that anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex was associated with enhanced working memory performance as indexed by the recognition accuracy in patients after a stroke.