Anodal transcranial direct-current stimulation and non-verbal intelligence in autism spectrum disorder: A randomized controlled trial.

AIM: To understand the impact of anodal transcranial direct-current stimulation (tDCS) on non-verbal intelligence in high-functioning young adults with autism spectrum disorder (ASD). METHOD: Thirty individuals with ASD were randomly divided into three groups receiving 2 mA, 20 minutes daily anodal tDCS for 10 sessions. Group A received 10 sham tDCS sessions, group B five real followed by five sham sessions, and group C received 10 real tDCS sessions. The total score of non-verbal intelligence was measured using the Test of Nonverbal Intelligence, Fourth Edition. The left dorsolateral prefrontal cortex (LDLPFC) was targeted using the International 10-20 electroencephalography system, and concurrent cognitive training was avoided. RESULTS: Group C demonstrated a mean difference of 4.10 (95% confidence interval 1.41-6.79; p = 0.005) in Test of Nonverbal Intelligence scores compared with group A, with an effect size of 0.47. No significant differences were observed between groups A and B (p = 0.296), or between groups B and C (p = 0.140). INTERPRETATION: Ten sessions of anodal tDCS to the LDLPFC led to improved non-verbal intelligence among individuals with ASD. These results emphasize the potential of tDCS as a discrete method for boosting cognitive abilities in the high-functioning population with ASD. Future studies with larger groups of participants and extended observation periods are necessary to validate these findings.

Long-term effects of transcranial direct current stimulation in the treatment of autism spectrum disorder: A randomized controlled trial.

AIM: To compare the efficacy of 0, 5, and 20 sessions of transcranial direct current stimulation (tDCS) for reducing symptoms of autism spectrum disorder (ASD). METHOD: Thirty-six male children with ASD (mean age 2 years 3 months, SD 4 months, age range 1 years 6 months-2 years 11 months) were balanced and stratified by age, sex, and baseline severity of ASD, to: (1) a control group that received 20 sessions of sham tDCS; (2) a 5-session tDCS group (5-tDCS) that received 5 sessions of active tDCS followed by 15 sessions of sham tDCS; and (3) a 20-session tDCS group (20-tDCS) that received 20 sessions of active tDCS. All groups participated in the special school activity of Khon Kaen Special Education Center, Thailand. The primary outcome was autism severity as measured by the Childhood Autism Severity Scale. RESULTS: The 5-tDCS and 20-tDCS groups evidenced greater reductions in autism severity than the control group at days 5 and 14, and months 6 and 12. There were no significant differences in the outcome between the 5- and 20-tDCS groups at any time point. Within-group analysis showed clinically meaningful improvements starting at month 6 for the participants in the control group, and clinically meaningful improvements starting on day 5 in both active tDCS groups, all of which were maintained to month 12. INTERPRETATION: The 5- and 20-session tDCS seems to reduce autism severity faster than sham tDCS. These effects maintained at least for 1 year. WHAT THIS PAPER ADDS: Twenty sessions of transcranial direct current stimulation (tDCS) were not superior to five sessions. Sham tDCS with a special school activity can reduce autism severity starting at 6 months after treatment. The benefits observed for 5 and 20 sessions of tDCS last for at least 12 months.

Brain laterality evaluated by F-18 fluorodeoxyglucose positron emission computed tomography in autism spectrum disorders.

Background and rationale: Autism spectrum disorder (ASD) is a neuropsychiatric disorder that has no curative treatment. Little is known about the brain laterality in patients with ASD. F-18 fluorodeoxyglucose positron emission computed tomography (F-18 FDG PET/CT) is a neuroimaging technique that is suitable for ASD owing to its ability to detect whole brain functional abnormalities in a short time and is feasible in ASD patients. The purpose of this study was to evaluate brain laterality using F-18 FDG PET/CT in patients with high-functioning ASD. Materials and methods: This case-control study recruited eight ASD patients who met the DSM-5 criteria, the recorded data of eight controls matched for age, sex, and handedness were also enrolled. The resting state of brain glucose metabolism in the regions of interest (ROIs) was analyzed using the Q.Brain software. Brain glucose metabolism and laterality index in each ROI of ASD patients were compared with those of the controls. The pattern of brain metabolism was analyzed using visual analysis and is reported in the data description. Results: The ASD group's overall brain glucose metabolism was lower than that of the control group in both the left and right hemispheres, with mean differences of 1.54 and 1.21, respectively. We found statistically lower mean glucose metabolism for ASD patients than controls in the left prefrontal lateral (Z = 1.96, p = 0.049). The left laterality index was found in nine ROIs for ASD and 11 ROIs for the control. The left laterality index in the ASD group was significantly lower than that in the control group in the prefrontal lateral (Z = 2.52, p = 0.012), precuneus (Z = 2.10, p = 0.036), and parietal inferior (Z = 1.96, p = 0.049) regions. Conclusion: Individuals with ASD have lower brain glucose metabolism than control. In addition, the number of ROIs for left laterality index in the ASD group was lower than control. Left laterality defects may be one of the causes of ASD. This knowledge can be useful in the treatment of ASD by increasing the left-brain metabolism. This trial was registered in the Thai Clinical Trials Registry (TCTR20210705005).

Transcranial Direct Current Stimulation in Treatment of Child Neuropsychiatric Disorders: Ethical Considerations.

Transcranial direct current stimulation (tDCS) is a noninvasive electrical stimulation performed using low electric currents passing through two electrodes. The provided current passes from the anode to the cathode and induces electric fields in the surface neurons. It then modulates synaptic plasticity and finally changes cortical excitability or improves clinical outcomes, which outlast after a duration of stimulation. Meta-analyses have supported the beneficial effects of tDCS treatments in child neuropsychiatric disorders. However, the study of vulnerable children remains controversial and is a great deal for ethical considerations. Because the developing brain has some important physiological differences from the matured brain, specifically less γ-aminobutyric acid (GABA)ergic inhibition and more myelination, the opportunity to modify neurological disorders to be close to the normal level in childhood after tDCS is likely to be higher than in adults. In contrast, these physiological differences may result in unexpected excitability in children's brains and were criticized to have an unsafe effect, specifically seizures, which is a serious adverse events. As mentioned above, using tDCS in children appears to be a double-edged sword and should be ethically considered prior to wide use. Assessing between benefits of tDCS treatment within the golden period of brain development and the risk of seizure provocation is important. Thus, this perspective article is aimed to exhibit broad concepts about the developing brain, tDCS in children, pathophysiology of neuropsychiatric disorders and tDCS beneficence, tDCS safety and tolerability in children, and missing good opportunities or taking risks in tDCS.

Brain Metabolite Changes After Anodal Transcranial Direct Current Stimulation in Autism Spectrum Disorder.

OBJECTIVES: Previous research has provided evidence that transcranial direct current stimulation (tDCS) can reduce severity of autism spectrum disorder (ASD); however, the exact mechanism of this effect is still unknown. Magnetic resonance spectroscopy has demonstrated low levels of brain metabolites in the anterior cingulate cortex (ACC), amygdala, and left dorsolateral prefrontal cortex (DLPFC) in individuals with ASD. The aim of this study was to investigate the effects of anodal tDCS on social functioning of individuals with ASD, as measured by the social subscale of the Autism Treatment Evaluation Checklist (ATEC), through correlations between pretreatment and posttreatment concentrations of brain metabolites in the areas of interest (DLPFC, ACC, amygdala, and locus coeruleus) and scores on the ATEC social subscale. METHODS: Ten participants with ASD were administered 1 mA anodal tDCS to the left DLPFC for 20 min over five consecutive days. Measures of the ATEC social subscale and the concentrations of brain metabolites were performed before and immediately after the treatment. RESULTS: The results showed a significant decrease between pretreatment and immediately posttreatment in the ATEC social subscale scores, significant increases in N-acetylaspartate (NAA)/creatine (Cr) and myoinositol (mI)/Cr concentrations, and a decrease in choline (Cho)/Cr concentrations in the left DLPFC and locus coeruleus after tDCS treatment. Significant associations between decreased ATEC social subscale scores and changed concentrations in NAA/Cr, Cho/Cr, and mI/Cr in the locus coeruleus were positive. CONCLUSION: Findings suggest that beneficial effects of tDCS in ASD may be due to changes in neuronal and glia cell activity and synaptogenesis in the brain network of individuals with ASD. Further studies with larger sample sizes and control groups are warranted.

The effects of transcranial direct current stimulation on metabolite changes at the anterior cingulate cortex in neuropathic pain: a pilot study.

BACKGROUND: Neuropathic pain (NP) in individuals with spinal cord injury (SCI) is both common and highly refractory to treatment. Primary motor cortex stimulation can relieve pain by interrupting the transmission of noxious information of descending pain modulatory systems including the anterior cingulate cortex (ACC). Previous research has shown that transcranial direct current stimulation (tDCS) can produce pain relief in individuals with NP. However, the underlying mechanisms for these effects are not yet understood. Research findings suggest the possibility that changes in brain metabolite concentrations produced by tDCS might explain some of these effects. For example, previous research has shown that SCI-related NP is associated with elevated levels of glutamine combined glutamate (Glx) per creatine (Glx/Cr). In addition, decreased N-acetylaspartate (NAA) has been observed in the ACC in individuals with chronic pain. METHODS: We used magnetic resonance spectroscopy (MRS) to study changes in NAA and Glx levels in the ACC after tDCS treatment. Ten patients with SCI with NP were given five daily anodal tDCS sessions, and an MRS evaluation was performed before and after treatment. RESULTS: The results showed treatment-related reductions in pain, and increases in both Glx/Cr and NAA/Cr in the ACC. The observed increase in NAA/Cr is consistent with the possibility that tDCS improves the descending pain modulation system by increasing the neuronal activity in the ACC. CONCLUSION: The findings suggest the possibility that tDCS's beneficial effects on neuropathic pain may be due, at least in part, to the changes it produces in Glx/Cr and NAA/Cr levels in the ACC. Additional research with larger samples sizes and a control group to evaluate this possibility is warranted.

Transient Changes in Brain Metabolites after Transcranial Direct Current Stimulation in Spastic Cerebral Palsy: A Pilot Study.

BACKGROUND: Muscle spasticity is a disability caused by damage to the pyramidal system. Standard treatments for spasticity include muscle stretching, antispastic medications, and tendon release surgeries, but treatment outcomes remain unsatisfactory. Anodal transcranial direct current stimulation (tDCS) in patients with muscle spasticity is known to result in significant improvement in spastic tone (p < 0.001). However, the mechanism of action by which tDCS treatment affects spasticity remains unclear. This pilot study aimed to investigate the effect of anodal tDCS upon brain metabolites in the left basal ganglia and ipsilateral primary motor cortex (M1) in children with spastic cerebral palsy (CP). MATERIALS AND METHODS: This study consisted of three steps: a baseline evaluation, a treatment period, and a follow-up period. During the treatment period, patients were given 20 min of 1 mA anodal tDCS over the left M1 for five consecutive days. Outcomes were compared between pre- and immediate posttreatment in terms of brain metabolites, Tardieu scales, and the quality of upper extremity skills test. RESULTS: Ten patients with spastic CP were enrolled. Following tDCS, there were significant increases in the ratio of N-acetylaspartate (NAA)/creatine (Cr) (p = 0.030), choline (Cho)/Cr (p = 0.043), and myoinositol (mI)/Cr (p = 0.035) in the basal ganglia. Moreover, increased glutamine-glutamate (Glx)/Cr ratio in the left M1 (p = 0.008) was found. In addition, we also observed improvements in the extent of spasticity and hand function (p = 0.028). CONCLUSION: Five consecutive days of anodal tDCS over the left M1 appeared statistically to reduce the degree of spasticity and increase NAA, Cho, mI, and Glx. Future research studies, involving a larger sample size of spastic CP patients undergoing tDCS is now warranted.

Transcranial Direct Current Stimulation for Treatment of Childhood Pharmacoresistant Lennox-Gastaut Syndrome: A Pilot Study.

BACKGROUND: Lennox-Gastaut syndrome (LGS) is a severe childhood epileptic syndrome with high pharmacoresistance. The treatment outcomes are still unsatisfied. Our previous study of cathodal transcranial direct current stimulation (tDCS) in children with focal epilepsy showed significant reduction in epileptiform discharges. We hypothesized that cathodal tDCS when applied over the primary motor cortex (M1) combined with pharmacologic treatment will be more effective for reducing seizure frequency in patients with LGS than pharmacologic treatment alone. MATERIALS AND METHODS: Study participants were randomized to receive either (1) pharmacologic treatment with five consecutive days of 2 mA cathodal tDCS over M1 for 20 min or (2) pharmacologic treatment plus sham tDCS. Measures of seizure frequency and epileptic discharges were performed before treatment and again immediately post-treatment and 1-, 2-, 3-, and 4-week follow-up. RESULT: Twenty-two patients with LGS were enrolled. Participants assigned to the active tDCS condition reported significantly more pre- to post-treatment reductions in seizure frequency and epileptic discharges that were sustained for 3 weeks after treatment. CONCLUSION: Five consecutive days of cathodal tDCS over M1 combined with pharmacologic treatment appears to reduce seizure frequency and epileptic discharges. Further studies of the potential mechanisms of tDCS in the LGS are warranted. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02731300 (https://register.clinicaltrials.gov).

The short-term effects of transcranial direct current stimulation on electroencephalography in children with autism: a randomized crossover controlled trial.

Abnormal synaptic maturation and connectivity are possible etiologies of autism. Previous studies showed significantly less alpha activity in autism than normal children. Therefore, we studied the effects of anodal tDCS on peak alpha frequency (PAF) related to autism treatment evaluation checklist (ATEC). Twenty male children with autism were randomly assigned in a crossover design to receive a single session of both active and sham tDCS stimulation (11 mA) over F3 (left dorsolateral prefrontal cortex). Pre- to postsession changes in a measure of cortical activity impacted by tDCS (PAF) and ATEC were compared between groups. We also examined the associations between pre- and postsession changes in the PAF and ATEC. The results show significant pre- to postsession improvements in two domains of ATEC (social and health/behavior domains) following active tDCS, relative to sham treatment. PAF also significantly increased at the stimulation site, and an increase in PAF was significantly associated with improvements in the two domains of ATEC impacted by tDCS. The findings suggest that a single session of anodal tDCS over the F3 may have clinical benefits in children with autism and that those benefits may be related to an increase in PAF.

The effects of transcranial direct current stimulation in patients with neuropathic pain from spinal cord injury.

OBJECTIVE: Transcranial direct current stimulation (tDCS) has demonstrated efficacy for reducing neuropathic pain, but the respective mechanisms remain largely unknown. The current study tested the hypothesis that pain reduction with tDCS is associated with an increase in the peak frequency spectrum density in the theta-alpha range. METHODS: Twenty patients with spinal cord injury and bilateral neuropathic pain received single sessions of both sham and anodal tDCS (2 mA) over the left primary motor area (M1) for 20 min. Treatment order was randomly assigned. Pre- to post-procedure changes in pain intensity and peak frequency of electroencephalogram spectral analysis were compared between treatment conditions. RESULTS: The active treatment condition (anodal tDCS over M1) but not sham treatment resulted in significant decreases in pain intensity. In addition, consistent with the study hypothesis, peak theta-alpha frequency (PTAF) assessed from an electrode placed over the site of stimulation increased more from pre- to post-session among participants in the active tDCS condition, relative to those in the sham tDCS condition. Moreover, we found a significant association between a decrease in pain intensity and an increase in PTAF at the stimulation site. CONCLUSIONS: The findings are consistent with the possibility that anodal tDCS over the left M1 may be effective, at least in part, because it results in an increase in M1 cortical excitability, perhaps due to a pain inhibitory effect of motor cortex stimulation that may influence the descending pain modulation system. Future research is needed to determine if there is a causal association between increased left anterior activity and pain reduction. SIGNIFICANCE: The results provide new findings regarding the effects of tDCS on neuropathic pain and brain oscillation changes.

Effect of anodal transcranial direct current stimulation on autism: a randomized double-blind crossover trial.

The aim of this study was to evaluate the Childhood Autism Rating Scale (CARS), Autism Treatment Evaluation Checklist (ATEC), and Children's Global Assessment Scale (CGAS) after anodal transcranial direct current stimulation (tDCS) in individuals with autism. Twenty patients with autism received 5 consecutive days of both sham and active tDCS stimulation (1 mA) in a randomized double-blind crossover trial over the left dorsolateral prefrontal cortex (F3) for 20 minutes in different orders. Measures of CARS, ATEC, and CGAS were administered before treatment and at 7 days posttreatment. The result showed statistical decrease in CARS score (P < 0.001). ATEC total was decreased from 67.25 to 58 (P < 0.001). CGAS was increased at 7 days posttreatment (P = 0.042). Our study suggests that anodal tDCS over the F3 may be a useful clinical tool in autism.

Reduction of spasticity in cerebral palsy by anodal transcranial direct current stimulation.

OBJECTIVE: To evaluate the anti-spasticity effects of anodal transcranial direct current stimulation (tDCS) in individuals with spastic cerebral palsy (CP). MATERIAL AND METHOD: Forty-six children and adolescents with cerebral palsy were randomly assigned to either active (1 mA anodal) or sham (placebo) tDCS over the left primary motor cortex (Ml) on five consecutive days. Both group also received routine physical therapy. Measures of spasticity and passive range of motion (PROM) were administered before treatment, immediately after treatment, and at 24- and 48-hours follow-up. RESULTS: Participants assigned to active tDCS treatment evidenced significantly more pre- to immediately post-treatment reductions in spasticity than participants assigned to the sham (p = 0.004, p

Pain reduction in myofascial pain syndrome by anodal transcranial direct current stimulation combined with standard treatment: a randomized controlled study.

BACKGROUND: Myofascial pain syndrome (MPS) in the shoulder is among the most prevalent pain problems in the middle-aged population worldwide. Evidence suggests that peripheral and central sensitization may play an important role in the development and maintenance of shoulder MPS. Given previous research supporting the potential efficacy of anodal transcranial direct current stimulation (tDCS) for modulating pain-related brain activity in individuals with refractory central pain, we hypothesized that anodal tDCS when applied over the primary motor cortex (M1) combined with standard treatment will be more effective for reducing pain in patients with MPS than standard treatment alone. METHODS AND MATERIALS: Study participants were randomized to receive either (1) standard treatment with 5 consecutive days of 1 mA anodal tDCS over M1 for 20 minutes; or (2) standard treatment plus sham tDCS. Measures of pain intensity, shoulder passive range of motion (PROM), analgesic medication use, and self-reported physical functioning were administered before treatment and again at posttreatment and 1-, 2-, 3-, and 4-week follow-up. RESULTS: Thirty-one patients with MPS were enrolled. Participants assigned to the active tDCS condition reported significantly more pretreatment to posttreatment reductions in pain intensity that were maintained at 1-week posttreatment, and significant improvement in shoulder adduction PROM at 1-week follow-up than participants assigned to the sham tDCS condition. CONCLUSIONS: Five consecutive days of anodal tDCS over M1 combined with standard treatment appears to reduce pain intensity and may improve PROM, faster than standard treatment alone. Further tests on the efficacy and duration of effects of tDCS in the treatment of MPS are warranted.

12-year retrospective study of Sturge-Weber syndrome and literature review.

OBJECTIVE: To review the clinical manifestations and neuroimaging features of patients with Sturge-Weber syndrome (SWS) treated at Srinagarind Hospital over a 12-year period. MATERIAL AND METHOD: A retrospective study of sixteen patients with SWS (9 males and 7 females) was conducted. The medical records, photographs, and neuroimaging studies were reviewed RESULTS: All patients had port-wine stain (PWS) involving the eyelid. Bilateral cutaneous lesions were revealed in four patients (25%). Glaucoma was the main ocular disease being diagnosed in 11 eyes of nine patients (56.25%); four eyes were finally blind. The cyclodestructive procedure and/or surgical treatment was required in four eyes. Other ocular abnormalities were refractive error dilated episcleral vessels, corneal abnormalities, tortuous retinal vessels, choroidal hemangioma, amblyopia, and strabismus. Twelve patients (75%) had neurological impairment including seizure, hemiparesis, headache, and delayed development. However the most common neurological manifestation was epilepsy (75%), which could be controlled with antiepileptic drugs. Neurological imaging was performed in the majority of cases (14 patients). Intracranial abnormalities were demonstrated in 11 patients (78.57%). These included cerebral atrophy (81.82%), cerebral calcification (54.55%), leptomeningeal angioma (27.27%), and enlarged choroidal plexus (27.27%). The ocular complication and intracranial abnormalities were usually ipsilateral to the PWS. One patient with unilateral PWS, however had bilateral intracranial lesion. CONCLUSION: Port-wine stains, glaucoma, and seizure were the most common clinical features of Sturge-Weber syndrome detected in the present study. Complete ophthalmic and neurological evaluation should be performed at the time ofdiagnosis. Multidisciplinary team management as well as lifelong follow-up is needed.

Hypoimmunoglobulinemia and protein C deficiency in a girl with Jacobsen syndrome: a case report.

Jacobsen syndrome is a rare contiguous gene syndrome caused by partial deletion of the long arm of chromosome 11. The typical clinical manifestations include physical growth retardation, mental retardation,facial dysmorphisms, congenital heart disease, thrombocytopenia, or pancytopenia. A Thai-Australian girl was born with multiple abnormalities. Typical features and her karyotype, 46, XX, del(ll) (q23-qter), confirmed Jacobson syndrome. She had many uncommon findings including upslanting palpebral fissures, tortuousity of retinal vessels and hypogammaglobulinemia. In addition, this case also presented with protein C deficiency, which has not been reported previously in Jacobsen syndrome. The patient was treated with phototherapy, intravenous antibiotic injection, and platelet transfusion in neonatal period. Cranioplasty was performed for prevention of the increased intracranial pressure at three months of age. Surgical correction for strabismus was in the treatment plan.

Transcranial direct current stimulation for treatment of refractory childhood focal epilepsy.

BACKGROUND: Cathodal transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation method for suppressing regional cortical excitability. We examine the safety and antiepileptic efficacy of cathodal tDCS in children with refractory focal epilepsy. Although a prior cathodal tDCS trial in adults with epilepsy revealed EEG improvement, neither the antiepileptic potential nor the safety and tolerability of tDCS has been tested in children. METHOD: The study consisted of three phases: 1) a 4-week pre-treatment monitoring period with vital sign measures, EEG, seizure diary, and baseline quality of life (QOL) questionnaire; 2) a single treatment with 1 mA cathodal tDCS for 20 min with cathode positioned over the seizure focus and anode on the contralateral shoulder; 3) follow-ups immediately after stimulation, and at 24, 48 h, and 4 weeks after tDCS with continued seizure diary and epileptic discharge counts on EEG; the QOL questionnaire was also repeated 4 weeks after stimulation. Patients were randomized to receive either single session active or sham tDCS 1 mA, 20 min. RESULTS: Thirty six children (6-15 years) with focal epilepsy were enrolled, 27 in active and 9 in sham group. All patients tolerated tDCS well. No serious adverse events occurred. Active tDCS treatment was associated with significant reductions in epileptic discharge frequency immediately and 24 and 48 h after tDCS. Four weeks after treatment, a small (clinically negligible but statistically significant) decrease in seizure frequency was also detected. CONCLUSION: A single session of cathodal tDCS improves epileptic EEG abnormalities for 48 h and is well-tolerated in children.

Clinical manifestations of Eosinophilic meningitis due to infection with Angiostrongylus cantonensis in children.

Eosinophilic meningitis, caused by the nematode Angiostrongylus cantonensis, is prevalent in northeastern Thailand, most commonly in adults. Data regarding clinical manifestations of this condition in children is limited and may be different those in adults. A chart review was done on 19 eosinophilic meningitis patients aged less than 15 years in Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Thailand. Clinical manifestations and outcomes were reported using descriptive statistics. All patients had presented with severe headache. Most patients were males, had fever, nausea or vomiting, stiffness of the neck, and a history of snail ingestion. Six patients had papilledema or cranial nerve palsies. It was shown that the clinical manifestations of eosinophilic meningitis due to A. cantonensis in children are different from those in adult patients. Fever, nausea, vomiting, hepatomegaly, neck stiffness, and cranial nerve palsies were all more common in children than in adults.

Transcranial Direct Current Stimulation in Neuropathic Pain.

Neuropathic pain (NP) is one of the most common problems contributing to suffering and disability worldwide. Unfortunately, NP is also largely refractory to treatments, with a large number of patients continuing to report significant pain even when they are receiving recommended medications and physical therapy. Thus, there remains an urgent need for additional effective treatments. In recent years, nonpharmacologic brain stimulation techniques have emerged as potential therapeutic options. Many of these techniques and procedures - such as transcranial magnetic stimulation, spinal cord stimulation, deep brain stimulation, and motor cortical stimulation - have very limited availability, particularly in developing countries. Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation procedure that has shown promise for effectively treating NP, and also has the potential to be widely available. This review describes tDCS and the tDCS procedures and principles that may be helpful for treating NP. The findings indicate that the analgesic benefits of tDCS can occur both during stimulation and beyond the time of stimulation. The mechanisms of cortical modulation by tDCS may involve various activities in neuronal networks such as increasing glutamine and glutamate under the stimulating electrode, effects on the µ-opioid receptor, and restoration of the defective intracortical inhibition. Additional research is needed to determine (1) the factors that may moderate the efficacy of tDCS, (2) the dose (e.g. number and frequency of treatment sessions) that results in the largest benefits and (3) the long-term effects of tDCS treatment.

Migraine prophylaxis by anodal transcranial direct current stimulation, a randomized, placebo-controlled trial.

BACKGROUND: Migraine is a common headache syndrome in adult populations. Prophylaxis is necessary to improve the quality of life but some patients with migraine have contraindication or suffer from side effects of medication, and therefore, establishing non-medical, neuromodulatory approaches is necessary. Past evidence had shown that consecutive motor cortex (M1) stimulation with anodal transcranial direct current stimulation (tDCS) was effective to relieve central pain. OBJECTIVE: To determine whether 20 consecutive days of the left M1 can be an effective prophylactic treatment for migraine. MATERIAL AND METHOD: Forty-two episodic migraine patients who had never received any prophylactic treatment, failed prophylactic treatment, or discontinued treatment due to adverse events were recruited in the present study. Patients were randomized to receive either active tDCS or sham tDCS 1mA, 20 m for 20 consecutive days and followed up for 12 weeks. Differences between and within groups were determined using repeated measures ANOVA. The level of significance was set at p < 0.05. RESULTS: Thirty-seven patients participated in the final analyses (active: n = 20, sham: n = 17). Between-groups comparison of attack frequency, pain intensity, and abortive medications used were performed at 4, 8, and 12 weeks after treatment. The results showed statistically significant reduction in attack frequency and abortive medications at week 4 and 8 after treatment. The pain intensity was statistically significant reduced at week 4, 8, and 12. All patients tolerated the tDCS well without any serious adverse events. CONCLUSION: The present study suggests that anodal M1 tDCS may be a safe and useful clinical tool in migraine prophylaxis. The mechanism of action of anodal tDCS on neuromodulation in migraine patients needs further investigation.

Basic knowledge of transcranial direct current stimulation.

BACKGROUND: Transcranial direct current stimulation (tDCS) was a neurophysiologic technique using weak electrical currents (1-2 mA) to modulate the activity of neurons in the brain. It was discovered in the 1960s, and then reintroduced by the reasonably well-controlled experiments 12 years ago. They suggested that electrodes placed on the head can produce noticeable neurological changes depended on the current direction. OBJECTIVE: To review a basic technique of the instrument, mechanism of action, and application in clinical researches of tDCS. MATERIAL AND METHOD: The tDCS studies were thoroughly reviewed in MEDLINE database using the key words "Transcranial direct current stimulation, tDCS, noninvasive brain stimulation, neurophysiologic technique" from 1998 to 2010. RESULTS: The basic technique of the instrument, mechanism of action, application in clinical researches such as stroke, pain syndrome and craving; safety, side effect, and precaution of tDCS are described. CONCLUSION: tDCS study is rapidly increasing and accepted as a noninvasive technique. It is easy to use and safe. The outcomes of tDCS in clinical researches are preferable with very little side effects.