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1.
Objective
Explore the possibility that transcranial direct current stimulation (tDCS) of the brain affects glial cells.Methods
Cable theory is used to estimate roughly transmembrane potential in neurons and glial cells. tDCS is additionally compared to neuronal stimulation techniques for which the mechanisms are well known.Results
Theoretical calculations indicated that tDCS can affect the glial transmembrane potential. The change is similar to what is physiologically observed in astrocytes during neuronal activation. In neurons, transmembrane potential changes are much weaker than the threshold for eliciting action potentials.Conclusions
Based on simplified cable theory, tDCS may affect glial cells’ transmembrane potential and thereby the balance of neurotransmitters. No physiological evidence or proof is available, however.Significance
It is an exciting possibility that tDCS could manipulate glial cells because they are active participants in brain function, and have multiple essential roles in the human brain. This approach may change greatly the therapeutic potential of tDCS, and also affects the safety considerations. 相似文献2.
Cornelius G. Bachmann Sebastian Muschinsky Michael A. Nitsche Roman Rolke Walter Magerl Rolf-Detlef Treede Walter Paulus Svenja Happe 《Clinical neurophysiology》2010,121(12):2083-2089
Objective
The aim of this single-blinded, complete crossover study was to evaluate the effects of tDCS on thermal and mechanical perception, as assessed by quantitative sensory testing (QST).Methods
QST was performed upon the radial part of both hands of eight healthy subjects (3 female, 5 male, 25–41 years of age). These subjects were examined before and after cathodal, anodal or sham tDCS, applied in a random order. TDCS was administered for 15 min at a 1 mA current intensity, with the active electrode placed over the left primary motor cortex and the reference electrode above the right orbit.Results
After cathodal tDCS, cold detection thresholds (CDT), mechanical detection thresholds (MDT), and mechanical pain thresholds (MPT) significantly increased in the contralateral hand, when compared to the baseline condition.Conclusions
Cathodal tDCS temporarily reduced the sensitivity to A-fiber mediated somatosensory inputs.Significance
Impairment of these somatosensory percepts suggests a short-term suppression of lemniscal or suprathalamic sensory pathways following motor cortex stimulation by cathodal tDCS. 相似文献3.
Objective
Controlled blinded studies using transcranial electrical stimulation (tES) paradigms need a validated sham stimulation paradigm since an itching or tingling sensation on the skin surface under the electrode can be associated with current flow.Methods
Here we investigated the skin perception thresholds of transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS) for current intensities ranging from 200 to 2000 μA and additional non-stimulation trials using a motor cortex–contralateral orbit montage in three different healthy subject groups: subjects naïve to tES methods, subjects with previous experience with these techniques and investigators, who use these methods in their research.Results
Taking the whole sample into consideration the 50% perception threshold for both tDCS conditions was at 400 μA while this threshold was at 1200 μA in the case of tRNS. Anodal and cathodal tDCS are indistinguishable regarding sites of perception. Experienced investigators show a significantly higher anodal stimulation detection rate when compared to the naïve group, furthermore investigators performed significantly better than naïve subjects in non-stimulation discrimination.Conclusions
tRNS has the advantage of higher cutaneous perception thresholds and lower response rates in when compared with tDCS. Further investigation in blinding methods (such as placebo itching) is warranted in order to improve sham control.Significance
As tRNS has been shown to have similar aftereffects as anodal tDCS, this finding points to the application of tRNS as a possible alternative with a better blinding control. 相似文献4.
Pedro Caldana Gordon Christoph Zrenner Debora Desideri Paolo Belardinelli Brigitte Zrenner André Russowsky Brunoni Ulf Ziemann 《Brain stimulation》2018,11(5):1024-1032
Background
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Objectives
To investigate effects of tDCS with different parameter settings applied to the left DLPFC on cortical responses, measured by resting-state electroencephalography (rs-EEG) and transcranial magnetic stimulation (TMS)-evoked/induced EEG responses.Methods
22 healthy subjects underwent 5 tDCS sessions with different tDCS parameter settings in a double-blinded randomized crossover design (1: 1.5?mA, anode left-DLPFC, cathode right-DLPFC; 2: 1.5?mA, cathode left-DLPFC, anode right-DLPFC; 3: 0.5?mA, anode left-DLPFC, cathode right-DLPFC; 4: 1.5?mA, anode left-DLPFC, cathode left deltoid muscle; 5: sham stimulation). Rs-EEG and TMS-EEG were recorded before and after tDCS.Results
Rs-EEG power spectrum analysis showed no difference comparing baseline with post stimulation in any of the tDCS conditions. TMS-EEG evoked potential amplitude decreased in parietal cortex after 1.5?mA left-DLPFC anodal tDCS, and TMS-induced gamma and theta oscillations decreased after all conditions using left-DLPFC anodal tDCS. Left-DLPFC cathodal tDCS did not lead to significant change. None of the post-intervention changes was different when comparing the effects across conditions, including sham.Conclusions
Our study does not provide evidence that a single tDCS session results in significant changes in rs-EEG, using the current stimulation parameters. Significant changes in EEG responses to TMS pulses were observed following the anodal 1.5?mA tDCS interventions, although these changes were not statistically significant in a group comparison. 相似文献5.
Airaksinen K Butorina A Pekkonen E Nurminen J Taulu S Ahonen A Schnitzler A M?kel? JP 《Clinical neurophysiology》2012,123(10):2010-2017
Objective
Parkinsonian patients have abnormal oscillatory activity within the basal ganglia-thalamocortical circuitry. Particularly, excessive beta band oscillations are thought to be associated with akinesia. We studied whether cortical spontaneous activity is modified by deep brain stimulation (DBS) in advanced Parkinson’s disease and if the modifications are related to the clinical symptoms.Methods
We studied the effects of bilateral electrical stimulation of subthalamic nucleus (STN) on cortical spontaneous activity by magnetoencephalography (MEG) in 11 Parkinsonian patients. The artifacts produced by DBS were suppressed by tSSS algorithm.Results
During DBS, UPDRS (Unified Parkinson’s Disease Rating Scale) rigidity scores correlated with 6-10 Hz and 12-20 Hz somatomotor source strengths when eyes were open. When DBS was off UPDRS action tremor scores correlated with pericentral 6-10 Hz and 21-30 Hz and occipital alpha source strengths when eyes open.Occipital alpha strength decreased during DBS when eyes closed. The peak frequency of occipital alpha rhythm correlated negatively with total UPDRS motor scores and with rigidity subscores, when eyes closed.Conclusion
STN DBS modulates brain oscillations both in alpha and beta bands and these oscillations reflect the clinical condition during DBS.Significance
MEG combined with an appropriate artifact rejection method enables studies of DBS effects in Parkinson’s disease and presumably also in the other emerging DBS indications. 相似文献6.
Objective
To investigate electrocortical responses to tonic cold pain by frequency-domain electroencephalogram (EEG) source analysis, and to identify potential electrocortical indices of acute tonic pain.Methods
Scalp EEG data were recorded from 26 healthy subjects under tonic cold pain (CP) and no-pain control (NP) conditions. EEG power spectra and the standardized low-resolution brain electromagnetic tomography (sLORETA) localized EEG cortical sources were compared between the two conditions in five frequency bands: 1–4 Hz, 4–8 Hz, 8–12 Hz, 12–18 Hz and 18–30 Hz.Results
In line with the EEG power spectral results, the source power significantly differed between the CP and NP conditions in 8–12 Hz (CP < NP) and 18–30 Hz (CP > NP) in extensive brain regions. Besides, there were also significantly different 4–8 Hz and 12–18 Hz source activities between the two conditions. Among the significant source activities, the left medial frontal and left superior frontal 4–8 Hz activities, the anterior cingulate 8–12 Hz activity and the posterior cingulate 12–18 Hz activity showed significant negative correlations with subjective pain ratings.Conclusions
The brain’s perception of tonic cold pain was characterized by cortical source power changes across different frequency bands in multiple brain regions. Oscillatory activities that significantly correlated with subjective pain ratings were found in the prefrontal and cingulate regions.Significance
These findings may offer useful measures for objective pain assessment and provide a basis for pain treatment by modulation of neural oscillations at specific frequencies in specific brain regions. 相似文献7.
van Wijk BC Willemse RB Peter Vandertop W Daffertshofer A 《Clinical neurophysiology》2012,123(11):2212-2219
Objective
Brain tumors may severely disrupt the structure and function of the brain. While abnormal low-frequency activity can be found around tumor borders, disrupted structural connectivity may also impinge on neural activity in distant brain regions and other frequency bands. We investigated how glioma in patients with normal motor functioning affects activity in primary motor areas (M1).Methods
Using magnetoencephalography in 12 patients with unilateral glioma located around the central sulcus, we studied activity in bilateral M1s in resting state and during movement with focus on motor-related mu (8–12 Hz) and beta rhythms (15–30 Hz). Principal component analysis served to test for differences in spectral content.Results
A shift was found towards lower frequencies for M1 in the tumor hemisphere compared to M1 in the healthy hemisphere, caused by an increase in mu and decrease in beta power. This pattern was observed both in resting state and during movement.Conclusions
This ‘slowing’ of brain oscillations in M1 resembles findings in patients with monohemispheric stroke and Parkinson’s disease. A loss of intra-cortical connectivity may account for these findings, possibly supplemented by tumor-induced changes in neurotransmitter systems.Significance
Motor functioning may be unaffected by a spectral shift of mu and beta oscillations. 相似文献8.
Background
Transcranial direct current stimulation (tDCS) has been found to improve working memory (WM) performance in healthy participants following a single session. However, results are mixed and the overall effect size is small. Interpretation of these results is confounded by heterogeneous study designs, including differences in tDCS dose (current intensity) and sham conditions used.Aims
We systematically investigated the effect of tDCS dose on working memory using behavioural and neurophysiological outcomes.Methods
In a single-blind parallel group design, 100 participants were randomised across five groups to receive 15?min of bifrontal tDCS at different current intensities (2?mA, 1?mA, and three sham tDCS conditions at 0.034?mA, 0.016?mA, or 0?mA). EEG activity was acquired while participants performed a WM task prior to, during, and following tDCS. Response time, accuracy and an event-related EEG component (P3) were evaluated.Results
We found no significant differences in response time or performance accuracy between current intensities. The P3 amplitude was significantly lower in the 0?mA condition compared to the 0.034?mA, 1?mA and 2?mA tDCS conditions. Changes in WM accuracy were moderately correlated with changes in frontal P3 amplitude (channel Fz) following tDCS compared to baseline levels (r?=?0.34).Conclusions
Working memory was not significantly altered by tDCS, regardless of dose. The P3 amplitude showed that stimulation at 1?mA, 2?mA and a sham condition (0.034?mA) had biological effects, with the largest effect size for 1?mA stimulation. These findings indicate higher sensitivity of neurophysiological outcomes to tDCS and suggests that sham stimulation previously considered inactive may alter neuronal function. 相似文献9.
Cristina Marzano Fabio Moroni Maurizio Gorgoni Lino Nobili Michele Ferrara Luigi De Gennaro 《Sleep medicine》2013,14(11):1112-1122
Objectives
We hypothesized that the brain shows specific and predictable patterns of spatial and temporal differences during sleep onset (SO) reflecting a temporal uncoupling of electrical activity between different cortical regions and a dissociated wakelike and sleeplike electrocortical activity in different cortical areas.Methods
We analyzed full-scalp electroencephalographic (EEG) recordings of 40 healthy subjects to investigate spatial and temporal changes of EEG activity across the wake-sleep transition. We quantified EEG sleep recordings by a fast Fourier transform (FFT) algorithm and by a better oscillation (BOSC) detection method to the EEG signals, which measured oscillatory activity within a signal containing a nonrhythmic portion.Results
The most representative spatial change at SO is the frontalization of slow-wave activity (SWA), while the θ activity, which mostly shares a similar temporal and spatial pattern with SWA, exhibits a temporo-occipital diffusion. The time course of these oscillations confirms that the changes of the dominant waves coexist with topographic changes. The waking occipital prevalence of α oscillations is progressively replaced by an occipital prevalence of θ oscillations. On the other hand, more anterior areas show a wide synchronization pattern mainly expressed by slow waves just below 4 Hz and by spindle oscillations.Conclusions
The whole pattern of results confirms that the centrofrontal areas showed an earlier synchronization (i.e., they fall asleep first). This finding implies a coexistence of wakelike and sleeplike electrical activity during sleep in different cortical areas. It also implies that the process of progressive brain disconnection from the external world as we fall asleep does not necessarily affect primary and higher-order cortices at the same time. 相似文献10.
Jana Wörsching Frank Padberg Stephan Goerigk Irmgard Heinz Christine Bauer Christian Plewnia Alkomiet Hasan Birgit Ertl-Wagner Daniel Keeser 《Brain stimulation》2018,11(5):998-1007
Background
Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been widely applied in cognitive neurosciences and advocated as a therapeutic intervention, e.g. in major depressive disorder. Although several targets and protocols have been suggested, comparative studies of tDCS parameters, particularly electrode montages and their cortical targets, are still lacking.Objective
This study investigated a priori hypotheses on specific effects of prefrontal-tDCS montages by using multimodal functional magnetic resonance imaging (fMRI) in healthy participants.Methods
28 healthy male participants underwent three common active-tDCS montages and sham tDCS in a pseudo-randomized order, comprising a total of 112 tDCS-fMRI sessions. Active tDCS was applied at 2?mA for 20?min. Before and after tDCS, a resting-state fMRI (RS fMRI) was recorded, followed by a task fMRI with a delayed-response working-memory (DWM) task for assessing cognitive control over emotionally negative or neutral distractors.Results
After tDCS with a cathode-F3/anode-F4 montage, RS-fMRI connectivity decreased in a medial part of the left PFC. Also, after the same stimulation condition, regional brain activity during DWM retrieval decreased more in this area after negative than after neutral distraction, and responses to the DWM task were faster, independent of distractor type.Conclusion
The current study does not confirm our a priori hypotheses on direction and localization of polarity-dependent tDCS effects using common bipolar electrode montages over PFC regions, but it provides evidence for montage-specific effects on multimodal neurophysiological and behavioral outcome measures. Systematic research on the actual targets and the respective dose-response relationships of prefrontal tDCS is warranted. 相似文献11.
F. Fregni I.C. Macedo L.N. Spezia-Adachi V.L. Scarabelot G. Laste A. Souza Paulo Roberto Stefani Sanches W. Caumo I.L.S. Torres 《Brain stimulation》2018,11(2):299-301
Background
Chronic stress (CS) is associated with a decrease in pain threshold caused by the changes in neural pain circuits. It can be associated to glucocorticoid imbalance with alterations in neural circuitry. Inhibition of stress-induced pain-related neural changes by using techniques that safely induce neuroplasticity such as transcranial direct current stimulation (tDCS) may prevent hyperalgesia triggered by CS.Objective
This study aimed to verify the effect of tDCS performed prior to CS exposure on nociceptive response.Methods
Thirty-two rats were distributed in the following groups: control; stress; sham-tDCS + stress; and tDCS + stress. Bicephalic active tDCS was performed for 8 consecutive days before the CS exposure. The pain threshold was evaluated using a hot plate and tail flick latency (TFL) tests.Results
The tDCS exposure increased the pain threshold on stressed rats.Conclusion
The data obtained indicate that the treatment with bicephalic active tDCS before chronic stress exposure prevents stress-induced hyperalgesia. 相似文献12.
Colleen K. Loo Mustafa M. Husain William M. McDonald Scott Aaronson John P. O&#x;Reardon Angelo Alonzo Cynthia Shannon Weickert Donel M. Martin Shawn M. McClintock Adith Mohan Sarah H. Lisanby 《Brain stimulation》2018,11(1):125-133
Background
Evidence suggests that transcranial Direct Current Stimulation (tDCS) has antidepressant effects in unipolar depression, but there is limited information for patients with bipolar depression. Additionally, prior research suggests that brain derived neurotrophic factor (BDNF) Val66Met genotype may moderate response to tDCS.Objective
To examine tDCS efficacy in unipolar and bipolar depression and assess if BDNF genotype is associated with antidepressant response to tDCS.Methods
130 participants diagnosed with a major depressive episode were randomized to receive active (2.5 milliamps (mA), 30 min) or sham (0.034 mA and two 60-second current ramps up to 1 and 0.5 mA) tDCS to the left prefrontal cortex, administered in 20 sessions over 4 weeks, in a double-blinded, international multisite study. Mixed effects repeated measures analyses assessed change in mood and neuropsychological scores in participants with at least one post-baseline rating in the unipolar (N = 84) and bipolar (N = 36) samples.Results
Mood improved significantly over the 4-week treatment period in both unipolar (p = 0.001) and bipolar groups (p < 0.001). Among participants with unipolar depression, there were more remitters in the sham treatment group (p = 0.03). There was no difference between active and sham stimulation in the bipolar sample. BDNF genotype was unrelated to antidepressant outcome.Conclusions
Overall, this study found no antidepressant difference between active and sham stimulation for unipolar or bipolar depression. However, the possibility that the low current delivered in the sham tDCS condition was biologically active cannot be discounted. Moreover, BDNF genotype did not moderate antidepressant outcome.13.
P. Fusar-Poli R. Smieskova M.J. Kempton B.C. Ho N.C. Andreasen S. Borgwardt 《Neuroscience and biobehavioral reviews》2013
Context
Antipsychotic treatment is the first-line treatment option for schizophrenia. Individual studies suggested they can significantly affect brain structure and account for progressive brain changes observed during the illness.Objectives
To quantitatively examine the effect of antipsychotics as compared to illness related factors on progressive brain changes in schizophrenia.Data sources
Electronic databases were searched until April 2012. All magnetic resonance imaging studies reporting progressive brain changes in schizophrenia subjects and antipsychotic exposure were retrieved.Study selection
30 longitudinal MRI studies with antipsychotic administration in schizophrenia patients met the inclusion criteria.Data extraction
Brain volumes before and after antipsychotic exposure, duration of illness, severity of psychotic symptoms as well as demographic, clinical, and methodological variables were extracted from each publication, or obtained directly from its authors.Data synthesis
The overall sample was of 1046 schizophrenia patients and 780 controls for a median duration of follow-up of 72.4 weeks. At baseline, patients showed significant whole brain volume reductions and enlarged lateral ventricle (LV) volumes compared to controls. No baseline volumetric abnormalities were detected in the gray matter volumes (GMV), white matter volumes, cerebrospinal fluid and caudate nucleus. Longitudinally, there were progressive GMV decreases and LV enlargements in patients but not in controls. The GMV decreases were inversely correlated with cumulative exposure to antipsychotic treatments, while no effects were observed for duration of illness or illness severity.Conclusions
Schizophrenia is characterized by progressive gray matter volume decreases and lateral ventricular volume increases. Some of these neuroanatomical alterations may be associated with antipsychotic treatment. 相似文献14.
Raphaëlle Richieri Laurent Boyer Romain Padovani Marc Adida Cécile Colavolpe Olivier Mundler Christophe Lançon Eric Guedj 《Progress in neuro-psychopharmacology & biological psychiatry》2012
Background
Functional neuroimaging studies have suggested similar mechanisms underlying antidepressant effects of distinct therapeutics.Objective
This study aimed to determine and compare functional brain patterns underlying the antidepressant response of 2 distinct protocols of repetitive transcranial magnetic stimulation (rTMS).Methods
99mTc-ECD SPECT was performed before and after rTMS of dorsolateral prefrontal cortex in 61 drug-resistant right-handed patients with major depression, using high frequency (10 Hz) left-side stimulation in 33 patients, and low frequency (1 Hz) right-side stimulation in 28 patients. Efficiency of rTMS response was defined as at least 50% reduction of the baseline Beck Depression Inventory score. We compared the whole-brain voxel-based brain SPECT changes in perfusion after rTMS, between responders and non-responders in the whole sample (p < 0.005, uncorrected), and separately in the subgroup of patients with left- and right-stimulation.Results
Before rTMS, the left- and right-prefrontal stimulation groups did not differ from clinical data and brain SPECT perfusion. rTMS efficiency (evaluated on % of responders) was statistically equivalent in the two groups of patients. In the whole-group of responder patients, a perfusion decrease was found after rTMS, in comparison to non-responders, within the left perirhinal cortex (BA35, BA36). This result was secondarily confirmed separately in the two subgroups, i.e. after either left stimulation (p = 0.017) or right stimulation (p < 0.001), without significant perfusion differences between these two subgroups.Conclusions
These data show that distinct successful rTMS protocols induce equivalent brain functional changes associated to antidepressive efficiency, consisting to a remote brain limbic activity decrease within the left perirhinal cortex. However, these results will have to be confirmed in a double-blind randomized trial using a sham control group. 相似文献15.
Casey S. Gilmore Patricia J. Dickmann Brent G. Nelson Greg J. Lamberty Kelvin O. Lim 《Brain stimulation》2018,11(2):302-309
Background
Impulsivity is a multidimensional personality trait observed across a variety of psychiatric disorders. Transcranial direct current stimulation (tDCS) applied over dorsolateral prefrontal cortex (DLPFC) has shown promise as an intervention to reduce impulsivity.Objective
To investigate the effects of tDCS paired with a decision-making task on risk-taking in Veterans with a clinical history of impulsive behavior.Methods
This was a randomized, single-blind, sham-controlled study. Participants performed the Balloon Analogue Risk Task (BART) while concurrently receiving either active or sham tDCS (right anodal/left cathodal over DLPFC) twice a day for five days. To evaluate generalization, the Risk Task was performed before and after the complete course of intervention. To evaluate durability, the BART and Risk Task were administered again at one and two month follow-up sessions.Results
Thirty Veterans participated: 15 received active tDCS and 15 received sham tDCS. For the trained BART task, individual growth curve analysis (IGC) examining individual variation of the growth rates over time showed no significant variations in individual trajectory changes over time (β = 0.02, p > 0.05). For the untrained Risk Task, IGC showed that the active tDCS group had a significant 46% decrease in risky choice from pre-to post-intervention, which persisted through the one and two month follow-up sessions. The sham tDCS group showed no significant change in risky choice from pre-to post-intervention.Conclusions
tDCS over DLPFC paired with a decision-making task effectively reduced risk-taking behavior in a group of Veterans with clinically-relevant impulsivity. Results suggest that this approach may be an effective neuroplasticity-based intervention for patients affected by impulsivity. 相似文献16.
Stevan Nikolin Christina Huggins Donel Martin Angelo Alonzo Colleen K. Loo 《Brain stimulation》2018,11(2):278-288
Background
Repeated sessions of transcranial direct current stimulation (tDCS) are increasingly used for therapeutic applications. However, adverse events (AEs) associated with repeated sessions have not been comprehensively evaluated.Objective
The aim of this study was therefore to evaluate the safety of repeated sessions of tDCS, examining AE risk relative to tDCS exposure. Further, to identify whether certain participant populations are particularly at risk from tDCS.Methods
A systematic review and meta-analysis included sham-controlled studies (up to June 2017) involving two or more tDCS sessions, spaced not more than a day apart. Data was extracted on AEs reported, total tDCS exposure (cumulative charge), and diagnostic groups (Healthy, Pain Disorder, Stroke, Neurocognitive Disorder, Neuropsychiatric Disorder, and Other). Univariate simple linear meta-regression analyses examined AE likelihood, comparing active and sham tDCS, with increasing exposure. Rates of AEs were compared for diagnostic groups.Results
158 studies (total 4130 participants) met inclusion criteria and were included for quantitative analyses. The incidence of AEs (examined per session, by proportion of participants, and by the number of studies reporting AEs) did not increase with higher levels of tDCS exposure. Furthermore, AE rates were not found to be greater for any diagnostic group.Conclusions
Little evidence was found to suggest that repeated sessions of active tDCS pose increased risk to participants compared to sham tDCS within the limits of parameters used to date. Increased risks associated with greater levels of exposure to tDCS, or rare and under-reported AEs, however, cannot be ruled out. 相似文献17.
Objective
To evaluate the importance of the distance between stimulation electrodes, in various montages, on the ability to induce sustained cortical excitability changes using transcranial direct and random noise stimulation.Methods
Twelve healthy subjects participated in four different experimental conditions. The stimulation electrode was always placed over the primary motor cortex; the reference electrode was placed at the contralateral orbit or at the ipsilateral/contralateral arm. MEPs were recorded in order to measure changes in cortical excitability over time.Results
The distance between the two electrodes correlates negatively with the duration and magnitude of induced after-effects.Conclusions
In particular when using extracephalic reference electrodes with transcranial electric stimulation techniques, the stimulation intensity has to be adapted to account for interelectrode distance.Significance
Electrode distance plays a critical role in the induction for stimulation after-effects in tDCS and tRNS studies, and must be taken into account in future studies and also when making comparisons with the published literature. 相似文献18.
Melanie K. Fleming John C. Rothwell Laszlo Sztriha James T. Teo Di J. Newham 《Clinical neurophysiology》2017,128(7):1389-1398
Objective
To assess the impact of electrode arrangement on the efficacy of tDCS in stroke survivors and determine whether changes in transcallosal inhibition (TCI) underlie improvements.Methods
24 stroke survivors (3–124 months post-stroke) with upper limb impairment participated. They received blinded tDCS during a motor sequence learning task, requiring the paretic arm to direct a cursor to illuminating targets on a monitor. Four tDCS conditions were studied (crossover); anodal to ipsilesional M1, cathodal to contralesional M1, bihemispheric, sham. The Jebsen Taylor hand function test (JTT) was assessed pre- and post-stimulation and TCI assessed as the ipsilateral silent period (iSP) duration using transcranial magnetic stimulation.Results
The time to react to target illumination reduced with learning of the movement sequence, irrespective of tDCS condition (p > 0.1). JTT performance improved after unilateral tDCS (anodal or cathodal) compared with sham (p < 0.05), but not after bihemispheric (p > 0.1). There was no effect of tDCS on change in iSP duration (p > 0.1).Conclusions
Unilateral tDCS is effective for improving JTT performance, but not motor sequence learning.Significance
This has implications for the design of future clinical trials. 相似文献19.
Géraldine Martens Nicolas Lejeune Anthony Terrence O&#x;Brien Felipe Fregni Charlotte Martial Sarah Wannez Steven Laureys Aurore Thibaut 《Brain stimulation》2018,11(5):982-990
Background
Patients with chronic disorders of consciousness face a significant lack of treatment options.Objective
We aimed at investigating the feasibility and the behavioral effects of home-based transcranial direct current stimulation (tDCS), applied by relatives or caregivers, in chronic patients in minimally conscious state (MCS).Methods
Each participant received, in a randomized order, 20 sessions of active and 20 sessions of sham tDCS applied over the prefrontal cortex for 4 weeks; separated by 8 weeks of washout. Level of consciousness was assessed using the Coma Recovery Scale-Revised before the first stimulation (baseline), at the end of the 20 tDCS sessions (direct effects) and 8 weeks after the end of each stimulation period (long-term effects). Reported adverse events and data relative to the adherence (i.e., amount of sessions effectively received) were collected as well.Results
Twenty-seven patients completed the study and 22 patients received at least 80% of the stimulation sessions. All patients tolerated tDCS well, no severe adverse events were noticed after real stimulation and the overall adherence (i.e., total duration of stimulation) was good. A moderate effect size (0.47 and 0.53, for modified intention to treat and per protocol analysis, respectively) was observed at the end of the 4 weeks of tDCS in favor of the active treatment.Conclusions
We demonstrated that home-based tDCS can be used adequately outside a research facility or hospital by patients' relatives or caregivers. In addition, 4 weeks of tDCS moderately improved the recovery of signs of consciousness in chronic MCS patients. 相似文献20.
Helen L. Carlson Patrick Ciechanski Ashley D. Harris Frank P. MacMaster Adam Kirton 《Brain stimulation》2018,11(1):94-103