Preconditioning with transcranial direct current stimulation sensitizes the motor cortex to rapid-rate transcranial magnetic stimulation and controls the direction of after-effects.

BACKGROUND: Rapid-rate repetitive transcranial magnetic stimulation (rTMS) can produce a lasting increase in cortical excitability in healthy subjects or induce beneficial effects in patients with neuropsychiatric disorders; however, the conditioning effects of rTMS are often subtle and variable, limiting therapeutic applications. Here we show that magnitude and direction of after-effects induced by rapid-rate rTMS depend on the state of cortical excitability before stimulation and can be tuned by preconditioning with transcranial direct current stimulation (tDCS). METHODS: Ten healthy volunteers received a 20-sec train of 5-Hz rTMS given at an intensity of individual active motor threshold to the left primary motor hand area. This interventional protocol was preconditioned by 10 min of anodal, cathodal, or sham tDCS. We used single-pulse TMS to assess corticospinal excitability at rest before, between, and after the two interventions. RESULTS: The 5-Hz rTMS given after sham tDCS failed to produce any after-effect, whereas 5-Hz rTMS led to a marked shift in corticospinal excitability when given after effective tDCS. The direction of rTMS-induced plasticity critically depended on the polarity of tDCS conditioning. CONCLUSIONS: Preconditioning with tDCS enhances cortical plasticity induced by rapid-rate rTMS and can shape the direction of rTMS-induced after-effects.     

Short- and long-lasting tinnitus relief induced by transcranial direct current stimulation

A significant proportion of the population suffers from tinnitus, a bothersome auditory phantom perception that can severely alter the quality of life. Numerous experimental studies suggests that a maladaptive plasticity of the auditory and limbic cortical areas may underlie tinnitus. Accordingly, repetitive transcranial magnetic stimulation (rTMS) has been repeatedly used with success to reduce tinnitus intensity. The potential of transcranial direct current stimulation (tDCS), another promising method of noninvasive brain stimulation, to relieve tinnitus has not been explored systematically. In a double-blind, placebo-controlled and balanced order design, 20 patients suffering from chronic untreatable tinnitus were submitted to 20 minutes of 1 mA anodal, cathodal and sham tDCS targeting the left temporoparietal area. The primary outcome measure was a change in tinnitus intensity or discomfort assessed with a Visual Analogic Scale (VAS) change-scale immediately after tDCS and 1 hour later. Compared to sham tDCS, anodal tDCS significantly reduced tinnitus intensity immediately after stimulation; whereas cathodal tDCS failed to do so. The variances of the tinnitus intensity and discomfort VAS change-scales increased dramatically after anodal and cathodal tDCS, whereas they remained virtually unchanged after sham tDCS. Moreover, several patients unexpectedly reported longer-lasting effects (at least several days) such as tinnitus improvement, worsening, or changes in tinnitus features, more frequently after real than sham tDCS. Anodal tDCS is a promising therapeutic tool for modulating tinnitus perception. Moreover, both anodal and cathodal tDCS seem able to alter tinnitus perception and could, thus, be used to trigger plastic changes.     

Repetitive transcranial magnetic stimulation improve tinnitus in normal hearing patients: a double-blind controlled, clinical and neuroimaging outcome study

Background and purpose:  Tinnitus is a frequent disorder which is very difficult to treat and there is compelling evidence that tinnitus is associated with functional alterations in the central nervous system. Targeted modulation of tinnitus-related cortical activity has been proposed as a promising new treatment approach. We aimed to investigate both immediate and long-term effects of low frequency (1 Hz) repetitive transcranial magnetic stimulation (rTMS) in patients with tinnitus and normal hearing.
Methods:  Using a parallel design, 20 patients were randomized to receive either active or placebo stimulation over the left temporoparietal cortex for five consecutive days. Treatment results were assessed by using the Tinnitus Handicap Inventory. Ethyl cysteinate dimmer-single photon emission computed tomography (SPECT) imaging was performed before and 14 days after rTMS.
Results:  After active rTMS there was significant improvement of the tinnitus score as compared to sham rTMS for up to 6 months after stimulation. SPECT measurements demonstrated a reduction of metabolic activity in the inferior left temporal lobe after active rTMS.
Conclusion:  These results support the potential of rTMS as a new therapeutic tool for the treatment of chronic tinnitus, by demonstrating a significant reduction of tinnitus complaints over a period of at least 6 months and significant reduction of neural activity in the inferior temporal cortex, despite the stimulation applied on the superior temporal cortex.     

Transcranial direct current stimulation preconditioning modulates the effect of high-frequency repetitive transcranial magnetic stimulation in the human motor cortex

Experimental studies emphasize the importance of homeostatic plasticity as a mean of stabilizing the properties of neural circuits. In the present work we combined two techniques able to produce short-term (5-Hz repetitive transcranial magnetic stimulation, rTMS) and long-term (transcranial direct current stimulation, tDCS) effects on corticospinal excitability to evaluate whether and how the effects of 5-Hz rTMS can be tuned by tDCS preconditioning. Twelve healthy subjects participated in the study. Brief trains of 5-Hz rTMS were applied to the primary motor cortex at an intensity of 120% of the resting motor threshold, with recording of the electromyograph traces evoked by each stimulus of the train from the contralateral abductor pollicis brevis muscle. This interventional protocol was preconditioned by 15 min of anodal or cathodal tDCS delivered at 1.5 mA intensity. Our results showed that motor-evoked potentials (MEPs) increased significantly in size during trains of 5-Hz rTMS in the absence of tDCS preconditioning. After facilitatory preconditioning with anodal tDCS, 5-Hz rTMS failed to produce progressive MEP facilitation. Conversely, when 5-Hz rTMS was preceded by inhibitory cathodal tDCS, MEP facilitation was not abolished. These findings may give insight into the mechanisms of homeostatic plasticity in the human cerebral cortex, suggesting also more suitable applications of tDCS in a clinical setting.     

Enhancing language performance with non-invasive brain stimulation--a transcranial direct current stimulation study in healthy humans

In humans, transcranial direct current stimulation (tDCS) can be used to induce, depending on polarity, increases or decreases of cortical excitability by polarization of the underlying brain tissue. Cognitive enhancement as a result of tDCS has been reported. The purpose of this study was to test whether weak tDCS (current density, 57 microA/cm(2)) can be used to modify language processing. Fifteen healthy subjects performed a visual picture naming task before, during and after tDCS applied over the posterior perisylvian region (PPR), i.e. an area which includes Wernicke's area [BA 22]. Four different sessions were carried out: (1) anodal and (2) cathodal stimulation of left PPR and, for control, (3) anodal stimulation of the homologous region of the right hemisphere and (4) sham stimulation. We found that subjects responded significantly faster following anodal tDCS to the left PPR (p<0.01). No decreases in performance were detected. Our finding of a transient improvement in a language task following the application of tDCS together with previous studies which investigated the modulation of picture naming latency by transcranial magnetic stimulation (TMS) and repetitive TMS (rTMS) suggest that tDCS applied to the left PPR (including Wernicke's area [BA 22]) can be used to enhance language processing in healthy subjects. Whether this safe, low cost, and easy to use brain stimulation technique can be used to ameliorate deficits of picture naming in aphasic patients needs further investigations.     

Brain transcranial direct current stimulation modulates motor excitability in mice

Shortly after the application of weak transcranial direct current stimulation (tDCS) to the animal and human brain, changes in corticospinal excitability, which mainly depend on polarity, duration and current density of the stimulation protocol, have been reported. In humans, anodal tDCS has been reported to enhance motor‐evoked potentials (MEPs) elicited by transcranial brain stimulation while cathodal tDCS has been shown to decrease them. Here we investigated the effects produced by tDCS on mice motor cortex. MEPs evoked by transcranial electric stimulation were recorded from forelimbs of 12 C57BL/6 mice, under sevofluorane anaesthesia, before and after (0, 5 and 10 min) anodal and cathodal tDCS (tDCS duration 10 min). With respect to sham condition stimulation (anaesthesia), MEP size was significantly increased immediately after anodal tDCS, and was reduced after cathodal tDCS (～20% vs. sham). Both effects declined towards basal levels in the following 10 min. Although the site and mechanisms of action of tDCS need to be more clearly identified, the directionality of effects of tDCS on mice MEPs is consistent with previous findings in humans. The feasibility of tDCS in mice suggests the potential applicability of this technique to assess the potential therapeutic options of brain polarization in animal models of neurological and neuropsychiatric diseases.     

Effects of transcranial direct current stimulation on working memory in patients with Parkinson's disease

OBJECTIVES: Cognitive impairment is a common feature in Parkinson's disease (PD) and is an important predictor of quality of life. Past studies showed that some aspects of cognition, such as working memory, can be enhanced following dopaminergic therapy and transcranial magnetic stimulation. The aim of our study was to investigate whether another form of noninvasive brain stimulation, anodal transcranial direct current stimulation (tDCS), which increases cortical excitability, is associated with a change in a working memory task performance in PD patients. METHODS: We studied 18 patients (12 men and 6 women) with idiopathic PD. The patients performed a three-back working memory task during active anodal tDCS of the left dorsolateral prefrontal cortex (LDLPFC), anodal tDCS of the primary motor cortex (M1) or sham tDCS. In addition, patients underwent two different types of stimulation with different intensities: 1 and 2 mA. RESULTS: The results of this study show a significant improvement in working memory as indexed by task accuracy, after active anodal tDCS of the LDLPFC with 2 mA. The other conditions of stimulation: sham tDCS, anodal tDCS of LDLPFC with 1 mA or anodal tDCS of M1 did not result in a significant task performance change. CONCLUSION: tDCS may exert a beneficial effect on working memory in PD patients that depends on the intensity and site of stimulation. This effect might be explained by the local increase in the excitability of the dorsolateral prefrontal cortex.     

Repetitive transcranial magnetic stimulation (rTMS) versus transcranial direct current stimulation (tDCS) in the management of patients with fibromyalgia: A randomized controlled trial

ObjectivesThe aim of this study was to compare the effects of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) on pain and quality of life in patients with fibromyalgia.MethodsThirty participants were randomized into two groups of 15 patients, to receive 3 sessions of either high-frequency (10 Hz) rTMS or 2 mA, 20 min anodal transcranial direct current stimulation over the left dorsolateral prefrontal cortex (DLPFC) over 1 week. Pain was assessed using a Visual Analog Scale (VAS) before treatment, immediately after treatment, 6 and 12 weeks later. Quality of life was evaluated using the Revised Fibromyalgia Impact Questionnaire (FIQR) and psychiatric symptoms were measured using the Depression Anxiety Stress Scale-21 Item (DASS-21) before treatment, and 6 and 12 weeks after treatment.ResultsFor the VAS there was a significant time-group interaction, showing that the behavior of two groups differed regarding changes of VAS in favor of the RTMS group (df = 1.73, F = 4.80, p = <0.016). Time-group interaction effect on DASS-21 and FIQR was not significant. 66.6% of patients in rTMS group and 26.6% of patients in tDCS group experienced at least a 30% reduction of VAS from baseline to last follow-up (p = 0.028).DiscussionWith the methodology used in this study, both rTMS and tDCS were safe modalities and three sessions of rTMS over DLPFC had greater and longer lasting analgesic effects compared to tDCS in patients with FM. However, considering the limitations of this study, further studies are needed to explore the most effective modality.     

Effects of transcranial direct current stimulation coupled with repetitive electrical stimulation on cortical spreading depression

We have recently shown that two techniques of brain stimulation - repetitive electrical stimulation (ES) (that mimics transcranial magnetic stimulation) and transcranial direct current stimulation (tDCS) - modify the velocity of cortical spreading depression (CSD) significantly. Herein we aimed to study the effects of these two techniques combined on CSD. Thirty-two Wistar rats were divided into four groups according to the treatment: sham tDCS/sham ES, sham tDCS/1 Hz ES, anodal tDCS/1 Hz ES, cathodal tDCS/1 Hz ES. Our findings show that 1 Hz ES reduced CSD velocity, and this effect was modified by either anodal or cathodal tDCS. Anodal tDCS induced larger effects than cathodal tDCS. Hereby CSD velocity was actually increased significantly after anodal tDCS/1 Hz ES. Our results show that combining two techniques of brain stimulation can modify significantly the effects of ES alone on cortical excitability as measured by the neurophysiological parameter of cortical spreading depression and therefore provide important insights into the effects of this new approach of brain stimulation on cortical activity.     

A study of the effectiveness of high-frequency left prefrontal cortex transcranial magnetic stimulation in major depression in patients who have not responded to right-sided stimulation

The objective of this study was to explore the response rate to high-frequency left-sided repetitive transcranial magnetic stimulation (rTMS) in patients who had failed to respond to right-sided low-frequency stimulation, and to investigate whether there was differential efficacy between stimulation at 5 or 10 Hz. Data from two randomized controlled trials were pooled. In both studies a group of patients were randomized to receive either 5- or 10-Hz left prefrontal rTMS after failing to respond to right-sided stimulation. These patients received blinded 5- or 10-Hz stimulation (but without a sham control) for a period of up to 4 weeks and outcomes were compared. There was a small but significant overall response to left-sided rTMS but no difference in response between the 5- and 10-Hz treatment conditions. There appears to be a significant but modest likelihood of response to left-sided TMS in patients who fail right-sided stimulation, but there is no difference in efficacy between 5- and 10-Hz stimulation.     

Modulatory effects of anodal transcranial direct current stimulation on perception and pain thresholds in healthy volunteers

Background and purpose: We aimed to evaluate whether transcranial direct current stimulation (tDCS) is effective in modulating sensory and pain perception thresholds in healthy subjects as to further explore mechanisms of tDCS in pain relief. Methods: Twenty healthy subjects received stimulation with tDCS under four different conditions of stimulation: anodal tDCS of the primary motor cortex (M1), dorsolateral prefrontal cortex (DLPFC), occipital cortex (V1), and sham tDCS. The order of conditions was randomized and counterbalanced across subjects. Perception threshold and pain threshold to peripheral electrical stimulation of the right index finger were evaluated by a blinded rater. Results: The results showed a significant effect of the interaction time versus stimulation condition for perception (P = 0.046) and pain threshold (P = 0.015). Post hoc comparisons revealed that anodal stimulation of M1 increased both perception (P < 0.001, threshold increase of 6.5%) and pain (P = 0.001, threshold increase of 8.3%) thresholds significantly, whilst stimulation of the DLPFC increased pain threshold only (P = 0.046, threshold increase of 10.0%). There were no significant effects for occipital or sham stimulation. Conclusions: These results show that both M1 and DLFPC anodal tDCS can be used to modulate pain thresholds in healthy subjects; thus, the mechanism of tDCS in modulating pain involves pathways that are independent of abnormal pain‐related neural activity.     

Transcranial direct current stimulation improves tinnitus perception and modulates cortical electrical activity in patients with tinnitus: A randomized clinical trial

ObjectivesThis study aims to determine whether transcranial direct current stimulation (tDCS): a) is effective in the treatment of tinnitus by decreasing its annoyance and severity; b) modulates the cortical electrical activity of such individuals.MethodsA double-blind, placebo-controlled clinical trial was conducted with 24 patients with tinnitus, randomized into two groups: Group 1 (n = 12) received anodal tDCS over the left temporoparietal area (LTA) and cathodal tDCS over the right dorsolateral prefrontal cortex (DLPFC) and Group 2 (n = 12) received placebo intervention. Tinnitus perception using a visual analog scale (VAS) and the Tinnitus Handicap Inventory (THI) questionnaire, in addition to electroencephalogram (EEG) was measured with eyes opened and closed at baseline and after the intervention. For the treatment, patients were subjected to five consecutive sessions of tDCS with the anodal electrode over the LTA and cathodal electrode over the right DLPFC (7 × 5 cm, 2 mA for 20 min). tDCS was turned off after 30 s in the sham group.ResultsActive tDCS significantly improved tinnitus annoyance and severity. It was associated with decreased beta and theta EEG frequency bands with eyes opened and decreased alpha frequency with eyes closed. sLORETA identified changes in frequency bands in the frontal, temporoparietal, and limbic regions. Finally, there were negative correlations between baseline EEG frequency bands and tDCS-induced change in tinnitus annoyance and severity.ConclusionsThese results demonstrate that tDCS modulates the EEG activity and alleviates tinnitus perception. This effect may be related to baseline EEG activity.     

Modulation of physiological mirror activity with transcranial direct current stimulation over dorsal premotor cortex

Humans have a natural tendency towards symmetrical movements, which rely on a distributed cortical network that allows for complex unimanual movements. Studies on healthy humans using rTMS have shown that disruption of this network, and particularly the dorsal premotor cortex (dPMC), can result in increased physiological mirror movements. The aim of the present set of experiments was to further investigate the role of dPMC in restricting motor output to the contralateral hand and determine whether physiological mirror movements could be decreased in healthy individuals. Physiological mirror movements were assessed before and after transcranial direct current stimulation (tDCS) over right and left dPMC in three conditions: bilateral, unilateral left and unilateral right stimulation. Mirror EMG activity was assessed immediately before, 0, 10 and 20 min after tDCS. Results show that physiological mirroring increased significantly in the hand ipsilateral to cathodal stimulation during bilateral stimulation of the dPMC, 10 and 20 min after stimulation compared to baseline. There was no significant modulation of physiological mirroring in the hand ipsilateral to anodal stimulation in the bilateral condition or following unilateral anodal or unilateral cathodal stimulation. The present data further implicate the dPMC in the control of unimanual hand movements and show that physiological mirroring can be increased but not decreased with dPMC tDCS.     

0.2-Hz repetitive transcranial magnetic stimulation has no add-on effects as compared to a realistic sham stimulation in Parkinson's disease.

To study the efficacy of 0.2-Hz repetitive transcranial magnetic stimulation (rTMS) on Parkinson's disease (PD), 85 patients with PD were enrolled into three groups: 1). motor cortical, 2). occipital, and 3). sham stimulation. A round coil was centered over the vertex in motor cortical stimulation, and over the inion in occipital stimulation. In one session, 100 stimuli of 0.2-Hz rTMS at an intensity of 1.1 times active motor threshold (AMT) were given. In sham stimulation, electric currents were given with electrodes fixed on the head to mimic the sensation in real stimulation. Each session was carried out once a week for the first 8 weeks. The Unified Parkinson Disease Rating Scale (UPDRS), Hamilton Rating Scale for Depression (HRSD) and subjective score (visual analogue scale) were assessed. There were no significant differences in clinical features among the three groups. Total and motor score of UPDRS were improved to the same extent by rTMS over Cz, inion, and sham stimulation. HRSD was improved by rTMS over Cz and sham stimulation in the same manner. Subjective score was not significantly improved by any methods of stimulation. 0.2-Hz rTMS at an intensity of 1.1 x AMT has only a placebo effect on PD. Our realistic sham stimulation maneuver must produce powerful placebo effects as a real stimulation.     

Effects of anodal transcranial direct current stimulation over lower limb primary motor cortex on motor learning in healthy individuals

Transcranial direct current stimulation (tDCS) is a neuromodulatory technique which alters motor functions in healthy humans and in neurological patients. Most studies so far investigated the effects of tDCS on mechanisms underlying improvements in upper limb performance. To investigate the effect of anodal tDCS over the lower limb motor cortex (M1) on lower limb motor learning in healthy volunteers, we conducted a randomized, single‐blind and sham‐controlled study. Thirty‐three (25.81 ± 3.85, 14 female) volunteers were included, and received anodal or sham tDCS over the left M1 (M1‐tDCS); 0.0625 mA/cm² anodal tDCS was applied for 15 min during performance of a visuo‐motor task (VMT) with the right leg. Motor learning was monitored for performance speed and accuracy based on electromyographic recordings. We also investigated the influence of electrode size and baseline responsivity to transcranial magnetic stimulation (TMS) on the stimulation effects. Relative to baseline measures, only M1‐tDCS applied with small electrodes and in volunteers with high baseline sensitivity to TMS significantly improved VMT performance. The computational analysis showed that the small anode was more specific to the targeted leg motor cortex volume when compared to the large anode. We conclude that anodal M1‐tDCS modulates VMT performance in healthy subjects. As these effects critically depend on sensitivity to TMS and electrode size, future studies should investigate the effects of intensified tDCS and/or model‐based different electrode positions in low‐sensitivity TMS individuals.     

Premotor transcranial direct current stimulation (tDCS) affects primary motor excitability in humans

Recent studies have shown that repetitive transcranial magnetic stimulation (rTMS) over the premotor cortex (PM) modifies the excitability of the ipsilateral primary motor cortex (M1). Transcranial direct current stimulation (tDCS) is a new method to induce neuroplasticity in humans non-invasively. tDCS generates neuroplasticity directly in the cortical area under the electrode, but might also induce effects in distant brain areas, caused by activity modulation of interconnected areas. However, this has not yet been tested electrophysiologically. We aimed to study whether premotor tDCS can modify the excitability of the ipsilateral M1 via cortico-cortical connectivity. Sixteen subjects received cathodal and anodal tDCS of the PM and eight subjects of the dorsolateral prefrontal cortex. Premotor anodal, but not premotor cathodal or prefrontal tDCS, modified selectively short intracortical inhibition/intracortical facilitation (SICI/ICF), while motor thresholds, single test-pulse motor-evoked potential and input–output curves were stable throughout the experiments. Specifically, anodal tDCS decreased intracortical inhibition and increased paired-pulse excitability. The selective influence of premotor tDCS on intracortical excitability of the ipsilateral M1 suggests a connectivity-driven effect of tDCS on remote cortical areas. Moreover, this finding indirectly substantiates the efficacy of tDCS to modulate premotor excitability, which might be of interest for applications in diseases accompanied by pathological premotor activity.     

Efficacy of different protocols of transcranial magnetic stimulation for the treatment of tinnitus: Pooled analysis of two randomized controlled studies

Objectives. Tinnitus is related to alterations in neuronal activity of auditory and nonauditory brain areas. Targeted modulation of these areas by repetitive transcranial magnetic stimulation (rTMS) has been proposed as a new therapeutic approach for chronic tinnitus. Methods. Two randomized, double-blind, parallel-group, controlled clinical trials were performed subsequently and pooled for analysis. A total of 192 tinnitus patients were randomly allocated to receive 10 stimulation sessions of either sham rTMS, PET-based neuronavigated 1 Hz rTMS, 1Hz r TMS over the left auditory cortex, or combined 20 Hz rTMS over the left frontal cortex, followed by 1 Hz rTMS over the left auditory cortex. Results. rTMS treatment was well tolerated and no severe side effects were observed. All active rTMS treatments resulted in significant reduction of the TQ as compared to baseline. The comparison between treatment groups failed to reach significant differences. The number of treatment responders was higher for temporal rTMS(38%) and combined frontal and temporal rTMS (43%), as compared to sham (6%). Conclusions. This large study demonstrates the safety and tolerability of rTMS treatment in patients with chronic tinnitus. While the overall effect did not prove superior to placebo, secondary outcome parameters argue in favour of the active stimulation groups, and specifically the combined frontal and temporal rTMS protocol.     

Motor cortex abnormalities in amyotrophic lateral sclerosis with transcranial direct-current stimulation

The aim of this study was to identify a neurophysiological marker of upper motoneuron involvement in patients with sporadic amyotrophic lateral sclerosis (ALS). For this purpose we evaluated the after-effects of transcranial direct-current stimulation (tDCS) on excitability of the motor cortex of eight ALS patients and eight healthy controls. Healthy controls showed a transient polarity-specific change in corticospinal excitability of about +/-45%, with anodal tDCS inducing facilitation and cathodal tDCS leading to inhibition, whereas no change could be induced in ALS patients after either type of tDCS. It is likely that the lack of tDCS after-effects in ALS is the result of alterations of the motoneuronal membrane or, alternatively, may represent an electrophysiological correlate of disordered glutamate neurotransmission. Further studies are warranted to confirm these results. The present findings may lead to a new, reliable electrophysiological marker of upper motoneuronal involvement in ALS.     

Steady-state auditory evoked fields reflect long-term effects of repetitive transcranial magnetic stimulation in tinnitus

ObjectivesEvidence of plastic changes in tinnitus has been demonstrated in functional brain imaging. Although repetitive transcranial magnetic stimulation (rTMS) has been shown to decrease steady-state auditory evoked fields (SSAEFs) in tinnitus, the long-term consequence remained unknown. In addition, association between plastic changes as reflected by hemispheric asymmetry and tinnitus handicap inventory (THI) before and after rTMS have not been addressed.MethodsTwelve tinnitus patients received rTMS and 12 received sham stimulation. Another 12 healthy participants served as the normal hearing controls. Patients responded to the THI before the 1st session and at one month after the final session of rTMS/sham stimulation. Changes in brain activity were assessed by measuring SSAEFs.ResultsSSAEFs remained decreased one month after rTMS compared to before treatment, along with a significant reduction in THI score. There was no significant effect between the index of hemispheric asymmetry and THI score.ConclusionsThe current study objectively demonstrated the long-term effects of rTMS on tinnitus using SSAEFs. A longitudinal study to develop an index using SSAEFs to assess the subjective severity of tinnitus is warranted.SignificanceThis study suggests the possible use of SSAEFs to assess the long-term effects of rTMS on tinnitus.     

Enhancement of precise hand movement by transcranial direct current stimulation

The effect of transcranial direct current stimulation (tDCS) on the precise nondominant hand movement was investigated by applying anodal stimulation over the right primary motor cortex. We recruited 14 healthy participants for this single-blind, sham-controlled crossover trial. A circle-drawing task was performed before, immediately after, and at 30 min after 20 min of 1 mA anodal or sham tDCS. Anodal tDCS, compared with sham stimulation, significantly improved the circle-drawing task compared with sham stimulation. The deviation area and path length of the task were significantly decreased after anodal tDCS application and were further enhanced at 30 min after stimulation. These results suggest that anodal tDCS over the primary motor cortex enhances the precise movement of the nondominant hand for 30 min in healthy participants.