Transcranial Direct Current Stimulation: Effects on Motor and Non-Motor Symptoms of Parkinson’s Disease

Introduction: In the last thirty years, brain neuromodulation techniques have been used as an alternative to pharmacological treatment of neurological disorders. Parkinson’s disease (PD) is a neurodegenerative disorder leading to bradykinesia, rest tremor, postural changes, and non-motor symptoms such as depression, anxiety, sleep disorders, pain, and cognitive decline that compromises executive functions (EFs), responsible for the orderly execution of behaviors and tasks of daily life and intentional and directed actions. To this date, a few studies with transcranial direct current stimulation (tDCS) have shown beneficial effects in PD patients concerning specific motor and non-motor symptoms, targeting the motor cortex and/or prefrontal regions. Objective: The main objective of this study was to evaluate the effects of left prefrontal tDCS across a broad spectrum of motor and non-motor symptoms of PD using established validated scales. Method: Single-blind randomized clinical trial with 18 volunteers with PD, aged between 45 and 80 years (66.1 ± 9.65), who met inclusion and exclusion criteria. Participants were submitted to assessments of motor and non-motor functions employing psychometric scales and tests to evaluate EFs and were randomly divided into two groups: control (sham stimulation) and experimental (active stimulation). All participants were involved in three separate tDCS sessions. The anode was positioned over the left dorsolateral prefrontal cortex and the cathode over the right supraorbital region, with a direct current intensity of 2 mA, lasting 20 minutes. At the end of the three sessions, all participants were reassessed. Results: Significant effects of tDCS on non-motor functions were observed for cognition (verbal fluency of actions, clock copy test, appointment by visual confrontation, and verbal memory with immediate free recall) and subjective assessment of sleep quality (overall restlessness and discomfort in the arms and legs at night, leg and arm cramps at night and distressing dreams). There was also an improvement in the rate of errors and successes for congruent and incongruent stimuli of the Stroop Test. The beneficial effects on motor function were decreased rigidity, improved gait, and greater agility in the finger-tapping test. Conclusion: Three tDCS sessions showed positive results for participants with PD, producing significant improvements in various motor and non-motor functions, including sleep quality, cognition, and EFs. Additionally, the present results indicate that tDCS neuromodulation of the left dorsolateral prefrontal cortex region is feasible, safe, and provides significant objective benefits for PD patients.

“Flow” Transcranial Direct Current Stimulation (tDCS) for Depression Treatment in a Primary Healthcare General Practice—An Open-Label Cohort Study Measuring Montgomery-Åsberg Depression Rating Scale (MADRS-S) Outcomes

Background: Flow FL-100 is a transcranial direct current stimulation (tDCS) device self-administered by a patient at home in combination with a software application delivered wellbeing behaviour therapy training. tDCS has evidence of effectiveness in treating symptoms of depression. Purpose/Aim: This post marketing study evaluated the effect of Flow on depression for primary care general practice patients with depression symptoms. Methods: Open-label patient cohort design with no control group. Inclusion criteria were aged 18 years or over and reporting depression symptoms. Participants self-administered five 30 minute tDCS sessions per week for the first three weeks, and then 3 sessions per week following this. Three, six and ten week assessment with participant self-report measure: Montgomery- Åsberg Depression Rating Scale (MADRS-S). Results: MADRS-S remission rates were between 29% - 30% at three weeks, 33% - 34% at six-weeks and 50% at 10-weeks treatment. There was a significant improvement in MADRS-S with large effect sizes at all time points. Conclusions: Flow tDCS can be delivered through a primary healthcare general practice service and patients will choose to use. Flow tDCS provides an effective depression treatment in addition and as an alternative to antidepressants and psychotherapy. tDCS has evidence as an effective depression treatment, and the widespread availability of tDCS in primary care general practice should be considered.

Positive Effect of Transcranial Direct Current Stimulation on Visual Verbal Working Memory in Patients with Attention-Deficit/Hyperactivity Disorder

Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of life. The dorsolateral prefrontal cortex (DLPFC) has been a good target site for transcranial direct current stimulation (tDCS) due to its intense involvement in working memory. In our 2018 study, tDCS improved visual-verbal working memory in healthy subjects. Objective: This study examines the effects of tDCS on ADHD patients, particularly on verbal working memory. Methods: We conducted an experiment involving verbal working memory of two modalities, visual and auditory, and a sustained attention task that could affect working memory in 9 ADHD patients. Active or sham tDCS was applied to the left DLPFC in a single-blind crossover design. Results: tDCS significantly improved the accuracy of visual-verbal working memory. In contrast, tDCS did not affect auditory-verbal working memory and sustained attention. Conclusion: tDCS to the left DLPFC improved visual-verbal working memory in ADHD patients, with important implications for potential ADHD treatments.

Transcranial direct current stimulation as early augmentation in adolescent obsessive compulsive disorder:A pilot proof-of-concept randomized control trial

BACKGROUND Transcranial direct current stimulation(tDCS)is proven to be safe in treating various neurological conditions in children and adolescents.It is also an effective method in the treatment of OCD in adults.AIM To assess the safety and efficacy of tDCS as an add-on therapy in drug-naive adolescents with OCD.METHODS We studied drug-naïve adolescents with OCD,using a Children’s Yale-Brown obsessive-compulsive scale(CY-BOCS)scale to assess their condition.Both active and sham groups were given fluoxetine,and we applied cathode and anode over the supplementary motor area and deltoid for 20 min in 10 sessions.Reassessment occurred at 2,6,and 12 wk using CY-BOCS.RESULTS Eighteen adolescents completed the study(10-active,8-sham group).CY-BOCS scores from baseline to 12 wk reduced significantly in both groups but change at baseline to 2 wk was significant in the active group only.The mean change at 2 wk was more in the active group(11.8±7.77 vs 5.25±2.22,P=0.056).Adverse effects between the groups were comparable.CONCLUSION tDCS is safe and well tolerated for the treatment of OCD in adolescents.However,there is a need for further studies with a larger sample population to confirm the effectiveness of tDCS as early augmentation in OCD in this population.

Transcranial direct current stimulation efficacy in trigeminal neuralgia

Trigeminal neuralgia is a severe,disabling pain and its deafferentation remains a challenge for health providers.Transcranial direct current stimulation is a non-invasive stimulation technique which finds new utility in managing pain.There-fore,the introduction of alternative,non-invasive,safe,and effective methods should be considered in treating patients with trigeminal neuralgia unresponsive to conventional treatment.

The Effects of the Geometry of a Current Collector with an Equal Open Ratio on Output Power of a Direct Methanol Fuel Cell

The open ratio of a current collector has a great impact on direct methanol fuel cell(DMFC)performance.Although a number of studies have investigated the influence of the open ratio of DMFC current collectors,far too little attention has been given to how geometry(including the shape and feature size of the flow field)affects a current collector with an equal open ratio.In this paper,perforated and parallel current collectors with an equal open ratio of 50%and different feature sizes are designed,and the corresponding experimental results are shown to explain the geometry effects on the output power of the DMFC.The results indicate that the optimal feature sizes are between 2 and 2.5 mm for both perforated and parallel flow field in the current collectors with an equal open ratio of 50%.This means that for passive methanol fuel cells,to achieve the highest output power,the optimal feature size of the flow field in both anode and cathode current collectors is between 2 and 2.5 mm under the operating mode of this experiment.The effects of rib and channel position are also investigated,and the results indicate that the optimum pattern depends on the feature sizes of the flow field.

Research and exploration of direct current power supply and distribution systems for Antarctic research stations

The power supply and distribution systems for Antarctic research stations have special characteristics.In light of a worldwide trend toward a gradual increase in the application of renewable energy,an analysis was performed to assess the feasibility of achieving a direct current power supply and distribution at Antarctic research stations by comparing the characteristics of direct current and alternating current electricity.Research was also performed on the status quo and future trends in direct current power supply and distribution systems in Antarctica research stations in combination with case studies.

Effect of transcranial direct current stimulation on supernumerary phantom limb pain in spinal cord injured patient:A case report

BACKGROUND Supernumerary phantom limb(SPL)sensation is the experience of additional limbs,either single or a pair of limbs.Unique to traumatic spinal cord injuries,we report effect of transcranial direct current stimulation(tDCS)on SPL pain in a patient with cervical cord injury.CASE SUMMARY The subject was a 57-year-old man who was diagnosed with complete spinal cord injury(C6/C5,motor level;C5/C5,sensory level;AIS-A)approximately three months ago.After a period of 2 wk,we administered anodal tDCS over the motor cortex for 15 minutes at an intensity of 1.5 mA.Following that treatment,the patient experienced a decrease of SPL pain intensity and frequency,which lasted for 1 week after the end of treatment.CONCLUSION Targeting the motor cortex through neuromodulation appears to be a promising option for the management of SPL pain.

Effect of Transcranial Direct Current Stimulation of Motor Cortex versus Insula Cortex on Chronic Post-Mastectomy Pain: Randomized Sham-Controlled Trial

Background: Transcranial direct current stimulation (tDCS) across cortical brain areas appears to improve various forms of pain, yet evidence of tDCS efficiency and ideal stimulation target is lacking. This study aimed to compare the add-on analgesic efficacy of concentric electrode transcranial direct current stimulation (CE-tDCS) stimulation over the primary motor cortex versus the insular cortex on the management of chronic postmastectomy pain. Method: Prospective randomized double-blind sham-controlled study enrolled eighty patients with chronic postmastectomy pain that were randomly assigned to four groups: active motor (AM), sham motor (SM), active insula (AI) and sham insula (SI) group, each received 5 sessions for 20-minute duration with 2 mA tDCS over the targeted area of the contralateral side of pain. Our primary outcome was VAS score, the secondary outcomes were VDS score, LANSS score and depression symptoms by HAM-D scores, assessment was done at 4 time points (prestimulation, after 5th session, 15th day and one month after the last session). Results: Both active tDCS groups (motor and insula) showed reduction of VAS (P Conclusion: Active tDCS stimulation either targeting the primary motor cortex or the insula cortex has add-on analgesic effect for controlling neuropathic chronic post mastectomy pain and the maximum effect was at 15 days after the last session.

Clinical Trial Demonstrates Efficacy of Transcranial Direct Current Stimulation (tDCS) in Improving Pain Management from Post-Laminectomy Syndrome

Chronic pain, a multidimensional experience affecting individuals’ sensory, cognitive, and emotional aspects, significantly impacts their quality of life. Post-laminectomy syndrome, a condition characterized by persistent back pain following spinal surgery, often leads to disability and increased healthcare utilization. Methods: This randomized, controlled, blind clinical trial aimed to investigate the efficacy of Transcranial Direct Current Stimulation (tDCS) in managing pain from post-laminectomy syndrome in patients. Twenty-four participants were assigned to three groups: sham stimulation, active stimulation over primary motor cortex (M1), or stimulation over dorsolateral prefrontal cortex (DLPFC). Stimulation was administered for five consecutive days, 20 minutes per session, using a current of 1.5 mA through 25 cm2 electrodes. Pain intensity was assessed using Visual Analog Scale (VAS) before, during, and after intervention. Results: An ANOVA model demonstrates significant reduction in pain intensity compared to baseline in VAS, (F(7, 285) = 12.292;p 0.001;Power = 1.000;η2p = 0.534), in tDCS applied to M1, after five days of intervention. After stimulation, a significant improvement was observed in WHOQoL-Bref Quality of life item 1 (p = 0.04), considering statistical significant difference p 0.05. Correlation between the variables: quality of life, depression, anxiety and pain also demonstrates reduction in depression and anxiety according to Beck’s Depression and Anxiety Inventories (BDI and BAI), p 0.05. This effect was not observed in DLPFC stimulation group. Patients who believed they received active stimulation, in sham group, demonstrated potential for effective blinding. Conclusion: The tDCS applied to primary motor cortex effectively improved pain management and psychiatry symptoms in post-laminectomy syndrome patients. The technique’s low cost, ease of use, and high tolerability make it a promising adjuvant therapy for chronic pain conditions like post-laminectomy syndrome.

Effects of direct current electric field on corrosion behaviour of copper, Cl- ion migration behaviour and dendrites growth under thin electrolyte layer

Effect of direct current electric field （DCEF） on corrosion behaviour of copper printed circuit board （PCB-Cu）, Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy （SEM） with energy dispersive spectrometer （EDS）. Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively.

An Empirical Direct Tunneling Current Expression for Ultra-Thin Oxide nMOSFETs

An empirical expression for the direct tunneling (DT) current is obtained.This expression can be used to calculate the DT current for nMOSFETs with ultra thin oxide when the oxide thickness is considered as an adjustable parameter.The results have good agreement with the experimental data.And the oxide thickness obtained is less than the value acquired from the capacitance voltage( C V )method.

基于暂态电流行波突变的LCC-MMC混合双极直流输电纵联方向保护

在直流线路中行波保护作为主保护应用广泛,但行波保护作为单端量的保护具有误动性较高且耐过渡电阻能力较差的缺点。在分析了行波在直流输电系统中传播特性的基础上,根据区内和区外故障时暂态电流行波变化方向的不同提出了一种基于暂态电流行波突变的LCC-MMC混合双极直流输电系统纵联方向保护。若故障时两侧暂态电流行波突变方向相同,则为区内故障,否则为区外故障。通过PSCAD和MATLAB的仿真结果表明,该保护能快速准确地识别故障,并且不受故障类型、过渡电阻以及故障发生位置距离的影响,因此具有一定的实用性。

扩展P-ROQR环流抑制策略在船舶MMC-MVDC电力系统中的应用

为了解决船舶中压直流(MVDC)电力系统中应用的模块化多电平变换器(MMC)存在的环流问题,分析自阻型MMC的拓扑结构及环流产生机理,采用基于2阶广义积分器(SOGI)的滤波器过滤环流中的直流分量。对于环流中的交流分量,提出一种基于比例降阶准比例谐振控制器的新型环流抑制器对其进行抑制。在MATLAB/Simulink软件中搭建船舶自阻型MMC-MVDC电力系统模型。仿真结果表明:所提策略能有效抑制环流中的交流分量;自阻型MMC应用于逆变侧时具有直流故障闭锁能力。所提策略应用于船舶MMC-MVDC电力系统的环流抑制效果优异,同时具有减少桥臂电流畸变,稳定子模块电容电压的作用。

基于CNN-BiGRU的高压直流输电线路故障识别

针对高压直流(high voltage direct current,HVDC)输电线路故障暂态行波具有时序性和强非线性的特点,导致高过渡电阻情况下故障识别率低的问题,提出基于卷积神经网络(convolutional neural networks,CNN)和双向循环门单元(bidirectional gate recurrent unit,BiGRU)的HVDC输电线路故障识别方法。首先,采用故障后整流侧的双极暂态电流行波作为特征向量,利用CNN提取全局特征,并从中剔除噪声和不稳定成分,完成对数据的降维处理。然后,采用BiGRU来捕获CNN提取到特征的前后时间信息,进一步提取数据中的时序特征,以实现HVDC输电线路故障识别。仿真结果表明:该方法可在不同故障地点以及不同过渡电阻下对单极接地、双极短路、雷击故障、雷击干扰共四种故障实现准确识别,可靠性高,具有较强的耐受过渡电阻能力,同时具备一定的抗噪性能。

直驱风电场经MMC-HVDC并网送端系统稳定性分析及振荡抑制

基于模块化多电平换流器MMC(modular multilevel converter)的高压直流输电HVDC(high voltage direct current transmission)因具有无源网络支撑等优势而被广泛应用于大容量新能源外送消纳。受电力电子设备交互作用等因素影响,送端系统易发生振荡失稳现象。首先,建立了直驱风电场经MMC-HVDC并网送端系统的小扰动线性化模型,分析了风场有功输出对系统稳定性的影响。然后,建立了MMC及风机并网变流器交流侧dq阻抗模型,从阻抗角度揭示了送端系统振荡失稳机理。进一步,提出了基于MMC交流电压控制外环q轴附加阻尼的振荡抑制策略,可满足系统满功率范围内的运行稳定性要求。最后,基于全比例模型的仿真结果验证了所提振荡抑制策略的有效性。

Harvesting Environment Mechanical Energy by Direct Current Triboelectric Nanogenerators

As hundreds of millions of distributed devices appear in every corner of our lives for information collection and transmission in big data era,the biggest challenge is the energy supply for these devices and the signal transmission of sensors.Triboelectric nanogenerator(TENG)as a new energy technology meets the increasing demand of today’s distributed energy supply due to its ability to convert the ambient mechanical energy into electric energy.Meanwhile,TENG can also be used as a sensing system.Direct current triboelectric nanogenerator(DC-TENG)can directly supply power to electronic devices without additional rectification.It has been one of the most important developments of TENG in recent years.Herein,we review recent progress in the novel structure designs,working mechanism and corresponding method to improve the output performance for DC-TENGs from the aspect of mechanical rectifier,tribovoltaic effect,phase control,mechanical delay switch and air-discharge.The basic theory of each mode,key merits and potential development are discussed in detail.At last,we provide a guideline for future challenges of DC-TENGs,and a strategy for improving the output performance for commercial applications.

多靶区经颅直流电刺激对健康成年人工作记忆-姿势控制双任务表现的影响

目的探究多靶区经颅直流电刺激(tDCS)和单靶区tDCS对健康成年人工作记忆-姿势控制双任务表现的影响,并比较两种刺激方案的调控效果。方法2020年11月至2021年2月,招募上海体育大学19例健康成年人,随机接受多靶区tDCS、单靶区tDCS和假刺激,任意两种刺激之间至少间隔1周。其中,多靶区tDCS的目标靶区为左侧背外侧前额叶(LDLPFC)和双侧初级运动皮质(M1);单靶区tDCS仅刺激L-DLPFC。在每种刺激前后,所有受试者进行单任务和双任务条件下的步行和站立平衡测试,双任务中的第二任务为N-back任务。刺激前后观察双任务姿势控制表现、双任务消耗(DTC)和工作记忆表现。结果刺激后,3种刺激间双任务步行的步幅变异性(F=3.792,P=0.029)、步幅变异性_DTC(F=3.412,P=0.040)以及双任务站立平衡的压心摆动速度(Vcop)(F=3.815,P=0.029)有显著性差异。与假刺激相比,多靶区tDCS后,步幅变异性(P=0.047)和Vcop(P=0.015)降低,步幅变异性_DTC有降低趋势(P=0.073);单靶区tDCS后,步幅变异性(P=0.011)、步幅变异性_DTC(P=0.014)和Vcop(P=0.025)均降低。与单靶区tDCS相比,多靶区tDCS后,压心摆动面积的双任务消耗降低(P=0.035)。3种刺激后受试者工作记忆表现改变无显著性差异(P>0.05)。结论多靶区tDCS和单靶区tDCS均可调控健康成年人的工作记忆-姿势控制双任务表现;且与单靶区tDCS相比,多靶区tDCS在调控站立平衡双任务姿势控制效果上具有一定优势。

间断直流磁场对Al-5Mg-3Zn-1Cu合金凝固组织和性能的影响

对Al-5Mg-3Zn-1Cu合金的凝固过程施加不同直流电压(0~300 V)和放电频率(0~20 Hz)以及占空比为30%的间断直流磁场,研究了间断直流磁场对其凝固组织及力学性能的影响。结果表明:间断直流磁场有效细化了合金的凝固组织,初生α-Al相由无磁场时的粗大枝晶变为细小的蔷薇状晶粒,第二相由粗大而连续的网格状结构变为细小而断续分布结构。随着直流电压的增加,合金的晶粒尺寸、第二相体积分数和长度均减小,抗压强度和断裂应变均先升后降;随着放电频率的增加,晶粒尺寸、第二相体积分数和长度均先减小后增大,抗压强度和断裂应变均先升后降。施加间断直流磁场后,合金的拉伸性能提高,断口中的准解理面减少,撕裂棱增多。当直流电压为200 V、放电频率为5 Hz时,合金的抗压强度和断裂应变最大,与无磁场时相比分别提高了31.6%和43%,抗拉强度和断后伸长率则分别提高了79.71%和83.3%。

Three modes of a direct-current plasma jet operated underwater to degrade methylene blue

A direct-current air plasma jet operated underwater presents three stable modes including an intermittently-pulsed discharge, a periodically-pulsed discharge and a continuous discharge with increasing the power voltage. The three discharge modes have different appearances for the plasma plumes. Moreover, gap voltage-current characteristics indicate that the continuous discharge is in a normal glow regime. Spectral lines from reactive species（OH, N2, N2^＋, Hα,and O） have been revealed in the emission spectrum of the plasma jet operated underwater.Spectral intensities emitted from OH radical and oxygen atom increase with increasing the power voltage or the gas flow rate, indicating that reactive species are abundant. These reactive species cause the degradation of the methylene blue dye in solution. Effects of the experimental parameters such as the power voltage, the gas flow rate and the treatment time are investigated on the degradation efficiency. Results indicate that the degradation efficiency increases with increasing the power voltage, the gas flow rate or the treatment time. Compared with degradation in the intermittently-pulsed mode or the periodically-pulsed one, it is more efficient in the continuous mode, reaching 98% after 21 min treatment.