Noninvasive Cortical Stimulation Research Articles

Comparison of Two Electrode Placement Methods in Transcranial Direct Current Stimulation for Parkinson's Disease

Purpose: Therapeutic electrical stimulation of deep brain structures, such as the subthalamic nucleus and the Globus Pallidus (GP), is widely accepted as a treatment tool for patients with Parkinson's Disease (PD). Electrical stimulation of the cerebral cortex with electrodes or transcranial stimulation can increase motor function among PD patients. The present study aimed to evaluate the effects of non-invasive cortical stimulation with simulation of transcranial Direct Current Stimulation (tDCS) technique on parts of the basal ganglia among PD patients.
 Materials and Methods: tDCS was simulated using two different electrode placement methods (anodal stimulation of the primary motor cortex (M1) and anodal stimulation of the Dorsolateral Prefrontal Cortex (DLPFC)) and We evaluated the excitation procedure in the target area based on the excitation current distribution in GP and Subthalamic Nucleus according to the patient's condition in both electrode methods. All simulations were performed using head Magnetic Resonance Imaging (MRI) images of four people with PD. Also, according to the excitation current distribution obtained from the previous step, we studied how the excitation current distributed in the target areas is affected by using a model of the basal ganglia so that based on the membrane potential of each excitation in these areas, in all four patients, we compare both electrode-installation methods in a functional way. The effectiveness of brain stimulation was also studied using a basal ganglia model. Considering the membrane potential of GP and Subthalamic Nucleus regions, the effectiveness of each electrode placement method was evaluated in the Basal Ganglia (BG) model.
 Results: According to the results, direct current stimulation was propagated through electrodes placed on the scalp throughout the model. Also, anodal stimulation of the M1 had a better stimulation of GP and subthalamic nucleus than anodal stimulation of the DLPFC.
 Conclusion: Although, the procedures for performing tDCS and invasive brain stimulation in PD are different, the results show that this treatment can be appropriate and improve motor function in patients with PD.

Adrenomedullary responses to non-invasive cortical stimulation in humans

Abstract Introduction: The discovery of cortical adrenomedullary projections in cebus monkeys suggests that similar pathways exist in humans. Notably, the major corticoadrenomedullary projection regions have human equivalents that can be stimulated non-invasively with repetitive transcranial magnetic stimulation (rTMS). If rTMS can be used to selectively modulate adrenomedullary activity, there may be significant therapeutic benefits for stress-, affective-, or neuroimmune-related disorders. Purpose: To assess resting and stress-induced adrenomedullary neuroendocrine responses to continuous (cTBS) and intermittent (iTBS) theta burst TMS in humans. Methods: 39 healthy young adults (14W) were randomly assigned to three counterbalanced sessions of iTBS (n=19) or cTBS (n=20). Stimulation was applied to motor cortical areas that contain the majority of adrenomedullary projections in non-human primates (primary motor cortex trunk region (M1TRUNK) and presupplementary motor area (preSMA)). The M1 leg region (M1LEG) was used as a spatial control. Stimulation locations were determined based on TMS-evoked electromyographic responses in the rectus abdominus (M1TRUNK) and vastus lateralis (M1LEG) or using a combination of fMRI activity and metanalytical structural coordinates (preSMA). All TMS procedures were performed with a 96mm curved double coil and stereotactic navigation. TBS was applied as 600 biphasic TMS pulses at 80% AMT. Corticoadrenomedullary activity and corticospinal excitability (CSE) were assayed before and after TBS, immediately after maximal exercise, and 60min and 90min after TBS based on plasma epinephrine concentrations and median MEP AUC, respectively. Initial analysis of adrenomedullary responses to rTMS were made with a 2 (protocol) x 3 (visit) x 5 (time-point) mixed methods ANOVA. Results and Conclusions: As expected, exercise resulted in a large epinephrine increase (p<0.0001, 8-fold) overall. Ongoing analysis indicates that target-specific changes in adrenomedullary activity are likely, and similar to CSE, may often be paradoxical. Our preliminary results also suggest that adrenomedullary responses to subthreshold rTMS are principally stress inducible. Research Category and Technology and Methods Translational Research: 10. Transcranial Magnetic Stimulation (TMS) Keywords: Adrenal Medulla, Cortex, Sympathetic Nervous System, Non-Invasive Brain Stimulation

Neurophysiological Basis of Deep Brain Stimulation and Botulinum Neurotoxin Injection for Treating Oromandibular Dystonia.

Oromandibular dystonia (OMD) induces severe motor impairments, such as masticatory disturbances, dysphagia, and dysarthria, resulting in a serious decline in quality of life. Non-invasive brain-imaging techniques such as electroencephalography (EEG) and magnetoencephalography (MEG) are powerful approaches that can elucidate human cortical activity with high temporal resolution. Previous studies with EEG and MEG have revealed that movements in the stomatognathic system are regulated by the bilateral central cortex. Recently, in addition to the standard therapy of botulinum neurotoxin (BoNT) injection into the affected muscles, bilateral deep brain stimulation (DBS) has been applied for the treatment of OMD. However, some patients' OMD symptoms do not improve sufficiently after DBS, and they require additional BoNT therapy. In this review, we provide an overview of the unique central spatiotemporal processing mechanisms in these regions in the bilateral cortex using EEG and MEG, as they relate to the sensorimotor functions of the stomatognathic system. Increased knowledge regarding the neurophysiological underpinnings of the stomatognathic system will improve our understanding of OMD and other movement disorders, as well as aid the development of potential novel approaches such as combination treatment with BoNT injection and DBS or non-invasive cortical current stimulation therapies.

Tinnitus as a comorbidity to depression and transcranial magnetic stimulation as a treatment for both - case report

IntroductionDepressive symptoms are common in individuals with tinnitus, however, the mechanisms of their interaction are not fully understood. There is neurobiological evidence that might help understanding the interplay between tinnitus and depression which, in turn, helps in making the right choice for treating both conditions.ObjectivesThis case report describes a 70-year old female patient that presented with tinnitus and depressive symptoms lasting for the past 5 years.MethodsThe patient showed limited treatment results with different antidepressants. The otorhinolaryngologist ruled out any possible somatic causes of her tinnitus. Tinnitus was causing her sleep disturbances, which worsened her everyday functioning that was already quite poor even further.ResultsAfter being administered with 30 rounds of TMS, her symptoms either completely resolved or at least reached a level that was adequate for her to start functioning normally on a day-to-day basis.ConclusionsTMS is a technique that provides non-invasive cortical stimulation, more specifically, when used for depression treatment it stimulates the left dorsolateral prefrontal cortex, a brain region synaptically connected to the limbic system involved in mood regulation that is proven to be hypoactive in depression. The limbic system is where tinnitus-related brain networks and regions involved in the pathophysiology of depression overlap. Further research is needed to deepen the understanding of this topic.DisclosureNo significant relationships.

Stroke Rehabilitation: AB No: 148: Therapeutic effect of Multi-target non-invasive Cortical Stimulation on Cognitive, Motor Domains and Gait in Sub acute Stroke Survivors- Case Series

Stroke Rehabilitation: AB No: 148: Therapeutic effect of Multi-target non-invasive Cortical Stimulation on Cognitive, Motor Domains and Gait in Sub acute Stroke Survivors- Case Series

Efeitos da etcc sobre o aprendizado motor em pessoas com doença de Parkinson / Effects of cts on motor learning in people with parkinson's disease

ASCHERIO, Alberto; SCHWARZSCHILD, Michael A. The epidemiology of Parkinson's disease: risk factors and prevention. The Lancet Neurology, v. 15, n. 12, p. 1257-1272, 2016. BENNINGER, David H.; HALLETT, Mark. Non-invasive brain stimulation for Parkinson’s disease: current concepts and outlook 2015. NeuroRehabilitation, v. 37, n. 1, p. 11-24,2015. BRUNONI, Andre Russowsky et al. A systematic review on reporting and assessment of adverse effects associated with transcranial direct current stimulation. International Journal of Neuropsychopharmacology, v. 14, n. 8, p. 1133-1145, 2011. CACABELOS, Ramón. Parkinson’s disease: from pathogenesis to pharmacogenomics.International journal of molecular sciences, v. 18, n. 3, p. 551, 2017. CHEN, Kai‐Hsiang Stanley; CHEN, Robert. Invasive and non‐invasive brain stimulation in Parkinson's disease: Clinical effects and future perspectives. Clinical Pharmacology &amp; Therapeutics, 2019. CHRISTOVA, Monica; RAFOLT, Dietmar; GALLASCH, Eugen. Cumulative effects of anodal and priming cathodal tDCS on pegboard test performance and motor cortical excitability. Behavioural brain research, v. 287, p. 27-33, 2015. FOX, Susan H. et al. International Parkinson and movement disorder society evidence‐based medicine review: Update on treatments for the motor symptoms of Parkinson's disease.Movement Disorders, v. 33, n. 8, p. 1248-1266, 2018. FREGNI, Felipe et al. Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson's disease. Movement disorders, v. 21, n. 10, p. 1693-1702, 2006. GRÜNER, Ulrike et al. 1 Hz rTMS preconditioned by tDCS over the primary motor cortex in Parkinson’s disease: effects on bradykinesia of arm and hand. Journal of neural transmission, v. 117, n. 2, p. 207-216, 2010. HAYES, Michael W. et al. Updates and advances in the treatment of Parkinson disease. The Medical journal of Australia, 2019. HUANG, Sheau-Ling et al. Minimal detectable change of the timed “up &amp; go” test and the dynamic gait index in people with Parkinson disease. Physical Therapy, v. 91, n. 1, p. 114- 121, 2011. JONES, Sarah E. et al. The five-repetition sit-to-stand test as a functional outcome measure in COPD. Thorax, p. 203- 576, 2013. LANG, Nicolas et al. Preconditioning with transcranial direct current stimulation sensitizes the motor cortex to rapid-rate transcranial magnetic stimulation and controls the direction of after- effects. Biological psychiatry, v. 56, n. 9, p. 634-639, 2004.LEE, Hyo Keun et al. Does transcranial direct current stimulation improve functional locomotion in people with Parkinson’s disease? A systematic review and meta-analysis. Journal of Neuroengineering and rehabilitation, v.16, n.1, p.84-96, 2019. LEFAUCHEUR, Jean-Pascal et al. Evidence-based guidelines on the therapeutic use of transcranial direct current stimulation (tDCS). Clinical Neurophysiology, v. 128, n. 1, p. 56- 92, 2017. PAPEN, Mitra Von et al. The effects of 1 Hz rTMS preconditioned by tDCS on gait kinematics in Parkinson’s disease. Journal of Neural Transmission, v. 121, n. 7, p. 743-754, 2014. SCHNEIDER, Ruth B.; IOURINETS, Julia; RICHARD, Irene H. Parkinson's disease psychosis: presentation, diagnosis and management. Neurodegenerative disease management, v. 7, n. 6, p. 365-376, 2017. OPARA, Józef et al. Motor assessment in Parkinsons disease. Ann Agric Environ Med, v. 24, n. 3, p. 411-415, 2017. PETERS, Denise M.; FRITZ, Stacy L.; KROTISH, Debra E. Assessing the reliability and validity of a shorter walk test compared with the 10-Meter Walk Test for measurements of gait speed in healthy, older adults. Journal of geriatric physical therapy, v. 36, n. 1, p. 24-30, 2013. REICH, S.G., SAVITT, J.M. Parkinson's Disease. MedIcal Clinics of North America. v. 103 n. 2, p. 337-350, 2018. RIBEIRO, Adriana Costa et al. Dopamine-independent effects of combining transcranial direct current stimulation with cued gait training on cortical excitability and functional mobility in Parkinson's disease. Journal of rehabilitation medicine, v. 48, n. 9, p. 819-823, 2016. RIBEIRO, Adriana Costa et al. Transcranial direct current stimulation associated with gait training in Parkinson’s disease: a pilot randomized clinical trial. Developmental neurorehabilitation, v. 20, n. 3, p. 121-128, 2017. TYSNES, Ole-Bjørn; STORSTEIN, Anette. Epidemiology of Parkinson’s disease. Journal of Neural Transmission, v. 124, n. 8, p. 901-905, 2017. VALENTINO, Francesca et al. Transcranial direct current stimulation for treatment of freezing of gait: A cross‐over study. Movement Disorders, v. 29, n. 8, p. 1064-1069, 2014.

Neuromodulation for Pain: A Comprehensive Survey and Systematic Review of Clinical Trials and Connectomic Analysis of Brain Targets

Background: Chronic pain is a debilitating condition that imposes a tremendous burden on health-care systems around the world. While frontline treatments for chronic pain involve pharmacological and psychological approaches, neuromodulation can be considered for treatment-resistant cases. Neuromodulatory approaches for pain are diverse in both modality and target and their mechanism of action is incompletely understood. Objectives: The objectives of this study were to (i) understand the current landscape of pain neuromodulation research through a comprehensive survey of past and current registered clinical trials (ii) investigate the network underpinnings of these neuromodulatory treatments by performing a connectomic mapping analysis of cortical and subcortical brain targets that have been stimulated for pain relief. Methods: A search for clinical trials involving pain neuromodulation was conducted using 2 major trial databases (ClinicalTrials.gov and the International Clinical Trials Registry Platform). Trials were categorized by variables and analyzed to gain an overview of the contemporary research landscape. Additionally, a connectomic mapping analysis was performed to investigate the network connectivity patterns of analgesic brain stimulation targets using a normative connectome based on a functional magnetic resonance imaging dataset. Results: In total, 487 relevant clinical trials were identified. Noninvasive cortical stimulation and spinal cord stimulation trials represented 49.3 and 43.7% of this count, respectively, while deep brain stimulation trials accounted for <3%. The mapping analysis revealed that superficial target connectomics overlapped with deep target connectomics, suggesting a common pain network across the targets. Conclusions: Research for pain neuromodulation is a rapidly growing field. Our connectomic network analysis reinforced existing knowledge of the pain matrix, identifying both well-described hubs and more obscure structures. Further studies are needed to decode the circuits underlying pain relief and determine the most effective targets for neuromodulatory treatment.

Non-invasive cortical stimulation: Transcranial direct current stimulation (tDCS).

Transcranial direct current stimulation (tDCS) is a re-emerging non-invasive brain stimulation technique that has been used in animal models and human trials aimed to elucidate neurophysiology and behavior interactions. It delivers subthreshold electrical currents to neuronal populations that shift resting membrane potential either toward depolarization or hyperpolarization, depending on stimulation parameters and neuronal orientation in relation to the induced electric field (EF). Although the resulting cerebral EFs are not strong enough to induce action potentials, spontaneous neuronal firing in response to inputs from other brain areas is influenced by tDCS. Additionally, tDCS induces plastic synaptic changes resembling long-term potentiation (LTP) or long-term depression (LTD) that outlast the period of stimulation. Such properties place tDCS as an appealing intervention for the treatment of diverse neuropsychiatric disorders. Although findings of clinical trials are preliminary for most studied conditions, there is already convincing evidence regarding its efficacy for unipolar depression. The main advantages of tDCS are the absence of serious or intolerable side effects and the portability of the devices, which might lead in the future to home-use applications and improved patient care. This chapter provides an up-to-date overview of a number tDCS relevant topics such as mechanisms of action, contemporary applications and safety. Furthermore, we propose ways to further develop tDCS research.

Noninvasive Cortical Stimulation for the Motor Function Rehabilitation of the Elderly with Chronic Back Pain: Preliminary Feasibility Study

Purpose: The purpose of this study is to investigate the effect of transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex (dlPFC) on pain intensity and functional strength in the elderly with chronic back pain. Methods: Sixteen elderly (72 ± 5.16 yrs) with chronic back pain participated in this randomized double-blinded crossover study. Each participant received both sham and 2-mA anodal currents over left dlPFC (cathode over the seventh cervical spinous process) for 20 min during 2 weeks for each current type with a washout period of 2 days between two different current stimulation periods. Pain intensity, functional lift strength, and the fear-avoidance response of all the participants were evaluated. Results: There were no significant differences in all pain-related variables between the 2mA stimulation period and the sham stimulation period. However, for results by within-group analysis in each stimulation period, we found significant improvements in pain intensity (p=.02), functional strength, (p=.006) and fear-avoidance response (p=.002) only after 2mA stimulation period, while there were no significant changes after sham stimulation. Conclusion: The current study demonstrated that anodal tDCS over dlPFC improve the painful feelings, followed by the functional strength for lifting task.

Anodal transcranial direct current stimulation and intermittent theta-burst stimulation improve deglutition and swallowing reproducibility in elderly patients with dysphagia.

Dysphagia in the elderly, known as presbydysphagia, has become a relevant public health problem in several countries. Swallowing disorders may be a consequence of different neurological disorders (secondary presbydysphagia) or the expression of the aging process itself (primary presbydysphagia). We aimed to test the therapeutic potential of two different non-invasive brain stimulation (NIBS) techniques in subjects with primary or secondary presbydysphagia. A blinded randomized controlled trial with crossover design was carried out in 42 patients, randomly assigned to anodal transcranial direct current stimulation (tDCS) or intermittent theta-burst stimulation (TBS) group. Both tDCS and TBS were applied for 5 consecutive days over the right swallowing motor cortex. The swallowing function was assessed before and 1 and 3months after the stimulation using the Dysphagia Outcome and Severity Scale (DOSS), scored based on clinical assessment and fiberoptic endoscopic evaluation of swallowing. An electrophysiological method was also applied to evaluate changes in the reproducibility of the swallowing behavior. Both real tDCS and TBS had beneficial effects on the swallowing function in patients with primary and secondary presbydysphagia. Anodal tDCS resulted in an improvement of 0.5 points in DOSS at 1-month follow-up (P=.014), whereas intermittent TBS induced an increase of 0.7 and 0.6 points at 1- and 3-month follow-up evaluations, respectively (P=.0001 and P=.005, respectively). Reproducibility of both the oral and pharyngeal phases of swallowing significantly increased at 1-month follow-up. Our results suggest that non-invasive cortical stimulation may be useful for dysphagia recovery in elderly patients.

Combined effect of repetitive transcranial magnetic stimulation and physical exercise on cortical plasticity.

Physical exercise can minimize dysfunction and optimize functional motor recovery after stroke by modulating cortical plasticity. However, the limitation of physical exercise is that large amounts of time and effort are necessary to significantly improve motor function, and even then, substantial exercise may not be sufficient to normalize the observed improvements. Thus, interventions that could be used to strengthen physical exercise-induced neuroplasticity may be valuable in treating hemiplegia after stroke. Repetitive transcranial magnetic stimulation seems to be a viable strategy for enhancing such plasticity. As a non-invasive cortical stimulation technique, repetitive transcranial magnetic stimulation is able to induce long-term plastic changes in the motor system. Recently, repetitive transcranial magnetic stimulation was found to optimize the plastic changes caused by motor training, thereby enhancing the long-term effects of physical exercise in stroke patients. Therefore, it is believed that the combination of repetitive transcranial magnetic stimulation and physical exercise may represent a superior method for restoring motor function after stroke.

A new developed non-invasive cortical stimulation on mirror neurons in children with autism spectrum disorders

Dysfunctional mirror neurons are associated with clinical features observed in children with autism spectrum disorder (ASD). Mirror neurons network spreads in the prefrontal cortex, premotor, primary motor, somatosensory, and inferior parietal areas. Herein, this study attempted to identify any potential therapeutic effects of a new developed bilateral anodal transcranial direct current stimulation (tDCS) applied over the left and right mirror neurons on the clinical characteristics of children with ASD. This study is a pilot randomized control trial. Fifty children with confirmed ASD medical diagnosis were divided equally and randomly into the tDCS treatment group and control group. The tDCS treatment group underwent ten sessions (20-minute duration, five per week) of bilateral anodal tDCS stimulation applied simultaneously over the left and right prefrontal and motor areas, whereas the control group underwent the same procedures but with the use of sham tDCS stimulation. Autism treatment evaluation checklists’ (ATEC) total score and sub-scores (language and communication; sociability; sensory awareness; and behavioral, health, and physical conditions) measured before and after tDCS treatment sessions of both groups. There were significant decreases in ATEC total score (p=0.014), sociability sub-score (p=0.021), and behavioral, health, and physical conditions sub-score (p=0.011) in the tDCS treatment group. No significant changes observed in the ATEC total score and sub-scores in the control group. bilateral anodal tDCS applied over mirror neurons showed potential therapeutic effects in children with ASD in terms of improvement in sociability, behavioral, health, and physical conditions with no reported side effects compared with the control group.

Assessment of motor cortex excitability in a child with hemispheric polymicrogyria and focal epilepsy by navigated transcranial magnetic stimulation: A case report

To evaluate motor cortex excitability as a function of lateralization relative to the seizure focus in child with intractable epilepsy undergoing navigated transcranial magnetic stimulation (nTMS) for presurgical mapping. nTMS is a method for focal noninvasive cortical stimulation where small intracranial electrical currents are generated by a powerful extracranial fluctuating magnetic field. Resting motor threshold (rMT), motor evoked potentials (MEPs), silent period (SP) serves as a measure of motor cortex excitability was assessed in both hands in 10 year old right-handed girl k/c of epilepsy and left side hemiparesis. There was significant difference in rMT, MEPs and SP between the hemispheres. The response of MEPs was more towards unaffected hemisphere. nTMS is a safe and tolerable procedure in children with intractable epilepsy. These results highlighted the potential for inducing lasting modulation of excitability in M1 by navigated TMS of the healthy M1, possibly reflecting modulation of interactions and demonstrating the potential use of such a paradigm.

Restorative Therapies after Stroke: Drugs, Devices, and Robotics

AbstractRestorative therapies aim to improve outcome by salvaging threatened brain, as with reperfusion or neuroprotective drugs and also by promoting plasticity within surviving neural tissue. Restorative therapies typically have a therapeutic time window measured in days and weeks and so have the potential to be assessed by a large fraction of patients with a new stroke. Examples of such brain repair therapies include growth factors, cell-based therapies, and devices. Positive clinical trials have been reported in human studies for several classes of restorative therapy after stroke. These include robotics, constrain-induced movement therapy (CIMT), and pharmacological therapy, such as levodopa and selective serotonin reuptake inhibitors. In addition, several forms of noninvasive cortical stimulation, such as rapid transcranial magnetic stimulation, transcranial direct current stimulation, and theta-burst stimulation, have shown promise in early phase studies. The current review gives a glimpse of the existing strategies, those on the anvil of implementation and those with a hope of launch in near future.

Down to Real Life: How to Perpetuate the Clinical Effects of Non-Invasive Cortical Stimulation

We will review the different strategies available to perform traditional intermittent weekly or fornightly maintenance sessions of treatment after a successful run of daily induction sessions are performed.

Chapter 37 - Transcranial magnetic stimulation

This review presents the neurophysiologic principles and clinical applications of transcranial magnetic stimulation (TMS) and other related techniques of noninvasive cortical stimulation. TMS can serve various purposes for diagnosis or treatment. Regarding diagnosis, TMS is mainly dedicated to the recording of motor evoked potentials (MEPs). MEP recording allows investigation of corticospinal conduction time and cortical motor control in clinical practice. Especially when using image-guided neuronavigation methods, MEP recording is a reliable method to perform functional mapping of muscle representation within the motor cortex. Using various types of paired-pulse paradigms, TMS allows the assessment of brain circuit excitability or plastic changes affecting these circuits. In particular, paired-pulse TMS paradigms are able to appraise the intracortical balance between inhibitory controls mediated by GABAergic neurotransmission and excitatory controls mediated by glutamatergic neurotransmission. Finally, TMS delivered as repetitive trains of stimulation (rTMS) may activate, inhibit, or otherwise interfere with the activity of neuronal cortical networks, depending on stimulus frequency and intensity, and brain-induced electric field configuration. Therefore by modifying brain functions, with after-effects lasting beyond the time of stimulation, rTMS opens exciting perspectives for therapeutic applications, especially in the domain of depression and chronic pain syndromes.

Effects of Acoustic Paired Associative Stimulation on Late Auditory Evoked Potentials

Paired associative stimulation (PAS), a form of non-invasive cortical stimulation pairing transcranial magnetic stimulation (TMS) with a peripheral sensory stimulus, has been shown to induce neuroplastic effects in the human motor, somatosensory and auditory cortex. The current study investigated the effects of acoustic PAS on late auditory evoked potentials (LAEP) and the influence of tone duration and placebo stimulation. In two experiments, 18 participants underwent a PAS with a 4 kHz paired tone of 400 ms duration using 200 pairs of stimuli (TMS-pulse over the left auditory cortex 45 ms after tone-onset) presented at 0.1 Hz. In Experiment 1 this protocol was contrasted with a protocol using a short paired tone of 23 ms duration (PAS-23 ms vs. PAS-400 ms). In Experiment 2 this PAS protocol was contrasted with sham stimulation (PAS-400 ms-sham vs. PAS-400 ms). Before and after PAS, LAEP were recorded for tones of 4 kHz (same carrier frequency as the paired tone) and 1 kHz as control tone. In Experiment 1, there was a significant difference between LAEP amplitudes of the 4 kHz tone after PAS-23 ms and PAS-400 ms with higher LAEP amplitudes after PAS-23 ms. Before both conditions, no difference could be detected. In Experiment 2 we observed a significant overall decrease in LAEP amplitudes pre to post PAS. Unspecific decreases of LAEP following PAS with a long paired tone (PAS-400 ms) might be related to habituation effects due to repeated presentation of sound stimuli which are not evident for PAS with a short paired tone (PAS-23 ms). Interpreting this result using the concept of temporal integration time allows us to discuss it in the context of spike-timing dependent plasticity.

The combined effect of non-invasive cortical stimulation and motor training on hand motor deficit in chronic stroke

A growing body of evidence supports the effectiveness of transcranial direct current stimulation (tDCS) in rehabilitation of patients with hand motor impairment in the chronic phase of stroke. Furthermore, it is assumed that the combination of stimulation- and practice-induced plasticity may be especially beneficial. Aim is to compare the combined effects of anodal tDCS and specific motor training (MT) to sham tDCS and MT (control) on hand motor deficit in patients with chronic stroke. A total of 30 patients were randomly assigned to an active treatment group (real tDCS + MT) or a control group (sham tDCS + MT) in this parallel, two-arm, double-blind, sham-controlled study. MT was administered for 45 min/day (10 sessions) and preceded by 20 minutes of either 2 mA anodal tDCS or sham tDCS over the ipsilesional primary motor cortex. A modified Jebsen–Taylor Hand Function Test (mJTt) was the primary outcome measure, with handgrip dynamometer and upper limb Fugl–Meyer (ULFM) assessments as secondary outcomes. A subset of 21 patients was additionally evaluated by transcranial magnetic stimulation measures of the primary motor cortex excitability The ANCOVA, controlling for baseline status (T0), showed a statistically significant time × group interaction for mJTt due to a statistically significant change over time in the active tDCS group compared to the sham tDCS group. In the active tDCS group, the mJTt time was significantly shorter both at the end of treatment (T2 vs. T0, decrease of 35.36 ± 22.90 s or 28.42 ± 14.56%) and at the follow-up (T3 vs. T0, decrease of 24.21 ± 24.66 s or 19.98 ± 17.49%). The active motor threshold decreased and the MEP amplitude increased. Our findings suggest that hand motor deficits in chronic stroke survivors can be reduced when intensive MT is primed with anodal tDCS over the ipsilesional primary motor cortex.

Non-invasive brain stimulation techniques for chronic pain

Non-invasive brain stimulation techniques for chronic pain

Non-invasive brain stimulation techniques for chronic pain.

Non-invasive brain stimulation techniques for chronic pain.