***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Due to the high interindividual response variability following transcranial direct current stimulation ( tDCS ) , it is apparent that further research of the long‐lasting effects of the stimulation technique is required . We aim ed to investigate interindividual variability following anodal tDCS and cathodal tDCS in a large‐scale prospect i ve cross‐over study . Motor cortex physiology measurements were obtained using transcranial magnetic stimulation ( TMS ) in 59 healthy participants comparing motor‐evoked potential ( MEP ) magnitudes following two tDCS paradigms : 1 mA anodal tDCS for 13 min and 1 mA cathodal tDCS for 9 min . Analysis compared MEP changes over time for both polarities . Additionally , we applied hierarchical cluster analysis to assess the dynamics of poststimulation changes . Overall , anodal tDCS result ed in a significant increase in corticospinal excitability lasting for 40 min poststimulation , whereas cathodal tDCS did not alter corticospinal excitability . Cluster analysis revealed for cathodal tDCS both a cluster showing significant stable MEP reduction and a second cluster displaying MEP increase over time . Two diametrical clusters were also found for anodal tDCS . Regardless of polarity , individuals with MEP increase following stimulation showed steeper cortical recruitment curves compared to the clusters with decreased MEP magnitudes . The observed findings confirm a bidirectional modulation of corticospinal excitability following 1 mA tDCS in separate subgroups and the relationship to cortical recruitment Transcranial direct current stimulation ( tDCS ) of the human motor cortex results in polarity-specific shifts of cortical excitability during and after stimulation . Anodal tDCS enhances and cathodal stimulation reduces excitability . Animal experiments have demonstrated that the effect of anodal tDCS is caused by neuronal depolarisation , while cathodal tDCS hyperpolarises cortical neurones . However , not much is known about the ion channels and receptors involved in these effects . Thus , the impact of the sodium channel blocker carbamazepine , the calcium channel blocker flunarizine and the NMDA receptor antagonist dextromethorphane on tDCS-elicited motor cortical excitability changes of healthy human subjects were tested . tDCS- protocol s inducing excitability alterations ( 1 ) only during tDCS and ( 2 ) eliciting long-lasting after-effects were applied after drug administration . Carbamazepine selectively eliminated the excitability enhancement induced by anodal stimulation during and after tDCS . Flunarizine result ed in similar changes . Antagonising NMDA receptors did not alter current-generated excitability changes during a short stimulation , which elicits no after-effects , but prevented the induction of long-lasting after-effects independent of their direction . These results suggest that , like in other animals , cortical excitability shifts induced during tDCS in humans also depend on membrane polarisation , thus modulating the conductance of sodium and calcium channels . Moreover , they suggest that the after-effects may be NMDA receptor dependent . Since NMDA receptors are involved in neuroplastic changes , the results suggest a possible application of tDCS in the modulation or induction of these processes in a clinical setting . The selective elimination of tDCS-driven excitability enhancements by carbamazepine proposes a role for this drug in focussing the effects of cathodal tDCS , which may have important future clinical applications Transcranial direct current stimulation ( tDCS ) uses a weak electric current to modulate neuronal activity . A neurophysiologic outcome measure to demonstrate reliable tDCS modulation at the group level is transcranial magnetic stimulation engendered motor evoked potentials ( MEPs ) . Here , we conduct a study testing the reliability of individual MEP response patterns following a common tDCS protocol . Fourteen participants ( 7m/7f ) each underwent nine r and omized sessions of 1 mA , 10 min tDCS ( 3 anode ; 3 cathode ; 3 sham ) delivered using an M1/orbito-frontal electrode montage ( sessions separated by an average of ~5.5 days ) . Fifteen MEPs were obtained prior to , immediately following and in 5 min intervals for 30 min following tDCS . TMS was delivered at 130 % resting motor threshold using neuronavigation to ensure consistent coil localization . A number of non-experimental variables were collected during each session . At the individual level , considerable variability was seen among different testing sessions . No participant demonstrated an excitatory response ≥20 % to all three anodal sessions , and no participant demonstrated an inhibitory response ≥20 % to all three cathodal sessions . Intra-class correlation revealed poor anodal and cathodal test – retest reliability [ anode : ICC(2,1 ) = 0.062 ; cathode : ICC(2,1 ) = 0.055 ] and moderate sham test – retest reliability [ ICC(2,1 ) = 0.433 ] . Results also revealed no significant effect of tDCS at the group level . Using this common protocol , we found the effects of tDCS on MEP amplitudes to be highly variable at the individual level . In addition , no significant effects of tDCS on MEP amplitude were found at the group level . Future studies should consider utilizing a more strict experimental protocol to potentially account for intra-individual response variations Evidence -based practice involves the use of evidence from systematic review s and r and omised controlled trials , but the extent of this evidence in physiotherapy has not previously been surveyed . The aim of this survey is to describe the quantity and quality of r and omised controlled trials and the quantity of systematic review s relevant to physiotherapy . The Physiotherapy Evidence Data base ( PEDro ) was search ed . The quality of trials was assessed with the PEDro scale . The search identified a total of 2,376 r and omised controlled trials and 332 systematic review s. The first trial was published in 1955 and the first review was published in 1982 . Since that time , the number of trials and review s has grown exponentially . The mean PEDro quality score has increased from 2.8 in trials published between 1955 and 1959 to 5.0 for trials published between 1995 and 1999 . There is a substantial body of evidence about the effects of physiotherapy . However , there remains scope for improvements in the quality of the conduct and reporting of clinical trials Transcranial direct current stimulation ( tDCS ) is a representative non-invasive brain stimulation method ( NIBS ) . tDCS increases cortical excitability not only in healthy individuals , but also in stroke patients where it contributes to motor function improvement . Recently , two additional types of transcranial electrical stimulation ( tES ) methods have been introduced that may also prove beneficial for stimulating cortical excitability ; these are transcranial r and om noise stimulation ( tRNS ) and transcranial alternating current stimulation ( tACS ) . However , comparison of tDCS with tRNS and tACS , in terms of efficacy in cortical excitability alteration , has not been reported thus far . We compared the efficacy of the three different tES methods for increasing cortical excitability using the same subject population and same current intensity . Fifteen healthy subjects participated in this study . Similar stimulation patterns ( 1.0 mA and 10 min ) were used for the three conditions of stimulation ( tDCS , tRNS , and tACS ) . Cortical excitability was explored via single-pulse TMS elicited motor evoked potentials ( MEPs ) . Compared with pre- measurements , MEPs significantly increased with tDCS , tACS , and tRNS ( p < 0.05 ) . Compared with sham measurements , significant increases in MEPs were also observed with tRNS and tACS ( p < 0.05 ) , but not with tDCS . In addition , a significant correlation of the mean stimulation effect was observed between tRNS and tACS ( p = 0.019 , r = 0.598 ) . tRNS induced a significant increase in MEP compared with the Pre or Sham at all time points . tRNS result ed in the largest significant increase in MEPs . These findings suggest that tRNS is the most effective tES method and should be considered as part of a treatment plan for improving motor function in stroke patients The purpose of this study was to determine whether anodal transcranial direct current stimulation ( tDCS ) delivered while performing a sustained submaximal contraction would increase time to task failure ( TTF ) compared to sham stimulation .  Healthy volunteers ( n = 18 ) performed two fatiguing contractions at 20 % of maximum strength with the elbow flexors on separate occasions . During fatigue task performance , either anodal or sham stimulation was delivered to the motor cortex for up to 20 minutes . Transcranial magnetic stimulation ( TMS ) was used to assess changes in cortical excitability during stimulation . There was no systematic effect of the anodal tDCS stimulation on TTF for the entire subject set ( n = 18 ; p = 0.64 ) . Accordingly , a posteriori subjects were divided into two tDCS-time groups : Full-Time ( n = 8) , where TTF occurred prior to the termination of tDCS , and Part-Time ( n = 10 ) , where TTF extended after tDCS terminated . The TTF for the Full-Time group was 31 % longer with anodal tDCS compared to sham ( p = 0.04 ) , whereas TTF for the Part-Time group did not differ ( p = 0.81 ) . Therefore , the remainder of our analysis addressed the Full-Time group . With anodal tDCS , the amount of muscle fatigue was 6 % greater at task failure ( p = 0.05 ) and the amount of time the Full-Time group performed the task at an RPE between 8–10 ( “ very hard ” ) increased by 38 % ( p = 0.04 ) compared to sham . There was no difference in measures of cortical excitability between stimulation conditions ( p = 0.90 ) . That the targeted delivery of anodal tDCS during task performance both increased TTF and the amount of muscle fatigue in a subset of subjects suggests that augmenting cortical excitability with tDCS enhanced descending drive to the spinal motorpool to recruit more motor units . The results also suggest that the application of tDCS during performance of fatiguing activity has the potential to bolster the capacity to exercise under conditions required to derive benefits due to overload PURPOSE Transcranial direct current stimulation ( tDCS ) has proven to be a useful tool for fundamental brain research as well as for attempts in therapy of neurological and psychiatric diseases by modulating neuronal plasticity . Little is understood about the effects of tDCS are influenced by hemispheric dominance , even less in terms of h and edness . The aim of our pilot study was to investigate whether tDCS induced neuroplastic changes may be different in right- and left-h and ed individuals due to existing differences in hemispheric lateralisation . METHODS We measured changes in motor evoked potentials ( MEPs ) after application of tDCS in 8 right-h and ers , 8 left-h and ers and 8 mixed-h and ers according to the Edinburgh H and edness Inventory ( EHI ) . In double-blind sessions , we applied either anodal or cathodal tDCS for 5 minutes for each hemisphere . RESULTS While motor thresholds ( MT ) seem to be not influenced by h and edness significantly , in right-h and ed subjects we reproduced the well-known effects of  tDCS :  anodal stimulation increased while cathodal stimulation decreased MEP amplitudes . However , left- and mixed-h and ed subjects differed from right-h and ed subjects . After anodal stimulation of the left hemisphere the increase of the MEP amplitudes was stronger in right h and ed subjects than in left and mixed h and ed subjects . Interestingly , after cathodal stimulation of the left hemisphere this difference was less marked . The stimulation of the right hemisphere showed the same tendency , but results were not significant . CONCLUSIONS For the first time , we are able to demonstrate that the modulating effects of tDCS on corticospinal excitability differ moderately in the left- and mixed-h and ed population compared to right-h and ed subjects . The shown differences according to h and edness should be taken into account in further studies The common aim of transcranial stimulation methods is the induction or alterations of cortical excitability in a controlled way . Significant effects of each individual stimulation method have been published ; however , conclusive direct comparisons of many of these methods are rare . The aim of the present study was to compare the efficacy of three widely applied stimulation methods inducing excitability enhancement in the motor cortex : 1 mA anodal transcranial direct current stimulation ( atDCS ) , intermittent theta burst stimulation ( iTBS ) , and 1 mA transcranial r and om noise stimulation ( tRNS ) within one subject group . The effect of each stimulation condition was quantified by evaluating motor-evoked-potential amplitudes ( MEPs ) in a fixed time sequence after stimulation . The analyses confirmed a significant enhancement of the M1 excitability caused by all three types of active stimulations compared to sham stimulation . There was no significant difference between the types of active stimulations , although the time course of the excitatory effects slightly differed . Among the stimulation methods , tRNS result ed in the strongest and atDCS significantly longest MEP increase compared to sham . Different time courses of the applied stimulation methods suggest different underlying mechanisms of action . Better underst and ing may be useful for better targeting of different transcranial stimulation techniques Weak transcranial direct current stimulation ( tDCS ) induces persisting excitability changes in the human motor cortex . These plastic excitability changes are selectively controlled by the polarity , duration and current strength of stimulation . To reveal the underlying mechanisms of direct current (DC)-induced neuroplasticity , we combined tDCS of the motor cortex with the application of Na(+)-channel-blocking carbamazepine ( CBZ ) and the N-methyl-D-aspartate (N 
    Output:
    
However , tACS effects on CSE were only significant when the stimulation frequency was ≥140 Hz .
This review provides evidence that tES has substantial effects on CSE in healthy individuals for a range of stimulus parameters