Hemisphere Stimulation Research Articles

Effect of a Neuromodulation Protocol Associated With Sports Training on the Precision Sports Performance of a Wheelchair Basketball Para-Athlete: A Case Study.

To investigate whether transcranial direct-current stimulation (tDCS) optimizes the performance of a wheelchair basketball player on precision tasks. A right-handed wheelchair basketball player (1.5 points functional class) with myelomeningocele (low lumbar level) participated in this case study. The tDCS neuromodulation protocol was applied throughout 10 interventions of 20 minutes with a current intensity of 2mA, simultaneously with sport-specific training, 3times a week for 4weeks. Anodic stimulation was performed on the right cerebellar hemisphere (CB2) and cathodic stimulation in the left dorsolateral prefrontal cortex. A control participant was submitted to a sham-tDCS stimulation protocol for the same period. Functional performance was assessed before the intervention and after the 5th and 10th interventions using "pass accuracy," "free-throw shooting," and "spot shot" tests. Outcome measures were compared using percentage differences between preintervention, intermediate intervention, and postintervention values. There was a gradual increase in the athlete's total and average scores in all tests performed, with an overall improvement of 78% between the baseline and final assessments, while the control participant had an overall improvement of 6.5%. The tDCS protocol was effective in improving performance in precision activities in a wheelchair basketball player.

The Effectiveness of Transcranial Magnetic Stimulation in Post Stroke Dysphagia, A Case Report

Background: A 72-year-old male, experiencing dysphagia and left-sided weakness for six months post-stroke, encountered challenges such as coughing and choking during the consumption of liquids and soft foods, along with a prolonged meal-swallowing process. Bilateral thrombotic infarction and left lateralization were revealed through Magnetic Resonance Imaging (MRI). Case: The Gugging Swallowing Screening Scale (GUSS) assessment demonstrated severe impairment with a total score of 7, persisting despite conventional physiotherapy attempts to improve swallowing function. Subsequently, repetitive transcranial magnetic stimulation (rTMS) was implemented, involving high-intensity stimulation in the ipsilesional hemisphere and low-intensity stimulation in the contralesional hemisphere. Remarkably, one month post-rTMS, the patient displayed significant progress, evidenced by an improved GUSS score of 15, indicating enhanced swallowing function. Discussion: This case emphasizes the positive impact of bilateral rTMS hemispheric stimulation on post-stroke dysphagia. The strategic application of high-intensity ipsilesional and low-intensity contralesional stimulation emerged as an effective intervention for alleviating swallowing difficulties. These findings highlight the potential of rTMS as an innovative therapeutic approach for persistent dysphagia following a stroke.

Neural substrates of individual differences in learning generalization via combined brain stimulation and multitasking training.

A pervasive limitation in cognition is reflected by the performance costs we experience when attempting to undertake two tasks simultaneously. While training can overcome these multitasking costs, the more elusive objective of training interventions is to induce persistent gains that transfer across tasks. Combined brain stimulation and cognitive training protocols have been employed to improve a range of psychological processes and facilitate such transfer, with consistent gains demonstrated in multitasking and decision-making. Neural activity in frontal, parietal, and subcortical regions has been implicated in multitasking training gains, but how the brain supports training transfer is poorly understood. To investigate this, we combined transcranial direct current stimulation of the prefrontal cortex and multitasking training, with functional magnetic resonance imaging in 178 participants. We observed transfer to a visual search task, following 1mA left or right prefrontal cortex transcranial direct current stimulation and multitasking training. These gains persisted for 1-month post-training. Notably, improvements in visual search performance for the right hemisphere stimulation group were associated with activity changes in the right hemisphere dorsolateral prefrontal cortex, intraparietal sulcus, and cerebellum. Thus, functional dynamics in these task-general regions determine how individuals respond to paired stimulation and training, resulting in enhanced performance on an untrained task.

Modulating risk-taking behavior with theta-band tACS

Although risk is prevalent in decision-making, the specific neural processes underlying risk-taking behavior remain unclear. Previous studies have suggested that frontal theta-band activity plays a crucial role in modulating risk-taking behavior. The functional relevance of theta in risk-taking behavior is yet to be clearly established and studies using noninvasive brain stimulation have yielded inconsistent findings. We aimed to investigate this relevance using transcranial alternating current stimulation (tACS) over right or left dorsolateral prefrontal cortex (DLPFC). We also studied the influence of stimulation intensity on risk-taking behavior and electrophysiological effects.We applied theta-band (6.5 Hz) tACS over the left (F3) and right (F4) DLPFC with lower (1.5 mA) and higher (3 mA) tACS intensities. We employed a single-blinded, sham-controlled, within-subject design and combined tACS with electroencephalography (EEG) measurements and the Maastricht Gambling Task (MGT) to elicit and evaluate risk-taking behavior.Our results show an increase in risk-taking behavior after left DLPFC stimulation at both intensities and a reduction of risk-taking behavior after 3 mA (and not 1.5 mA) right DLPFC stimulation compared to sham. Further analyses showed a negative correlation between resting-state frontal theta-power and risk-taking behavior. Overall, frontal theta-power was increased after left, but not right, theta-band tACS independent of stimulation intensity.Our findings confirm the functional relevance of frontal theta-band activity in decision-making under risk and the differential role of left and right DLPFC. We also were able to show that stimulation intensity did have an effect on behavioral responses, namely risk-taking behavior. Significant right hemisphere stimulation effects were observed only after high-intensity stimulation. Nevertheless, electrophysiological effects were only significant after left DLPFC stimulation, regardless of tACS intensity. Furthermore, the results indicate the role of the baseline frontal theta-power in the direction of behavioral effects after theta-band tACS.

Protocol for a single-blind randomized clinical trial to test the efficacy of bilateral transcranial magnetic stimulation on upper extremity motor function in patients recovering from stroke

BackgroundNo consensus currently exists regarding the optimal protocol for repetitive transcranial magnetic stimulation (rTMS) treatment of upper-extremity motor dysfunction after stroke. Studies have shown that combined low- and high-frequency stimulation (LF-HF-rTMS) of the bilateral cerebral hemispheres is more effective than sham stimulation or stimulation of one cerebral hemisphere alone in treating motor dysfunction in the subacute stage of stroke. The efficacy of this protocol in the convalescence phase of stroke has rarely been reported, and its mechanism of action has not been clarified. In this study, we designed a prospective, single-blind, randomized controlled trial to investigate the efficacy and safety of different stimulation regimens for the treatment of upper extremity motor disorders in patients with convalescent stage stroke and aimed to explore the underlying mechanisms based on biomarkers such as brain-derived neurotrophic factor (BDNF).MethodsSeventy-six subjects will be randomly divided into combined, low-frequency, high-frequency, and control groups based on the proportion of 1:1:1:1, with 19 cases in each group. All groups will have conventional rehabilitation, on top of which the combined group will receive 1 Hz rTMS in the unaffected hemisphere and 10 Hz rTMS in the affected hemisphere. The low-frequency group will be administered 1 Hz rTMS in the unaffected hemisphere and sham stimulation in the contralateral hemisphere. The high-frequency group will be administered 10 Hz rTMS in the affected hemisphere and contralateral sham stimulation. The control group will receive bilateral sham stimulation. Assessments will be performed at baseline, after 2 weeks of treatment, and at post-treatment follow-up at week 6. The primary outcomes are FMA-UE (Fugl-Meyer assessment-upper extremity), latency, and serum BDNF levels. The secondary outcomes are the National Institute of Health Stroke Scale (NIHSS), Brunnstrom staging (BS), modified Ashworth scale (MAS), Modified Barthel Index (MBI), central motor conduction time (CMCT), precursor proteins of mature BDNF (proBDNF), and matrix metalloproteinase-9 (MMP-9) levels. Adverse events, such as headaches and seizures, will be recorded throughout the study.DiscussionThe findings of this study will help develop optimal stimulation protocols for motor recovery in stroke patients and identify biomarkers that respond to post-stroke motor rehabilitation, for better guidance of clinical treatment.Trial registrationThe study protocol was passed by the Medical Research Ethics Committee of the General Hospital of Ningxia Medical University on January 1, 2022 (no. KYLL-2021–1082). It was registered into the Chinese Clinical Trials Registry on May 22, 2022 (no. ChiCTR2200060201). This study is currently in progress.Graphical

Comparing electrical stimulation functional mapping with subdural electrodes and stereoelectroencephalography.

Electrical stimulation mapping (ESM) is the clinical standard for functional localization with subdural electrodes (SDE). As stereoelectroencephalography (SEEG) has emerged as an alternative option, we compared functional responses, afterdischarges (ADs), and unwanted ESM-induced seizures (EISs) between the two electrode types. Incidence and current thresholds for functional responses (sensory, motor, speech/language), ADs, and EISs were compared between SDE and SEEG using mixed models incorporating relevant covariates. We identified 67 SEEG ESM and 106 SDE ESM patients (7207 and 4980 stimulated contacts, respectively). We found similar incidence of language and motor responses between electrode types; however, more SEEG patients reported sensory responses. ADs and EISs occurred less commonly with SEEG than SDE. Current thresholds for language, face motor, and upper extremity (UE) motor responses and EIS significantly decreased with age. However, they were not affected by electrode type, premedication, or dominant hemispheric stimulation. AD thresholds were higher with SEEG than with SDE. For SEEG ESM, language thresholds remained below AD thresholds up to 26 years of age, whereas this relationship was inverse for SDE. Also, face and UE motor thresholds fell below AD thresholds at earlier ages for SEEG than SDE. AD and EIS thresholds were not affected by premedication. SEEG and SDE have clinically relevant differences for functional brain mapping with electrical stimulation. Although evaluation of language and motor regions is comparable between SEEG and SDE, SEEG offers a higher likelihood of identifying sensory areas. A lower incidence of ADs and EISs, and a favorable relationship between functional and AD thresholds suggest superior safety and neurophysiologic validity for SEEG ESM than SDE ESM.

Underpinning the neurological source of executive function following cross hemispheric tDCS stimulation

Transcranial direct current stimulation (tDCS) is a promising technique for enhancement of executive functions in healthy as well as neurologically disturbed patients. However, the evidence regarding the neuropsychological and behavioral change with neurophysiological shifts as well as the mechanism of tDCS action as evidenced by activation of neuronal sources important for executive functions have remained unaddressed. The study thereby endeavors to (1) determine the neuropsychological, behavioral, and neurophysiological change induced with five sessions of bilateral tDCS stimulation and (2) identify putative neuronal sources related to the executive functions responsible for neuropsychological and behavioral change. For this single blinded study, a total of 40 healthy participants, randomly allocated to active (n = 19) or sham (n = 21) groups completed five sessions of 2 mA tDCS stimulation administered over Dorso-Lateral Prefrontal Cortex (DLPFC) (F3 as anode, F4 as cathode). Repeated measure analysis was performed on neuropsychological (Everyday Memory Questionnaire and Mindful Attention Awareness Scale), and behavioral assessment (n-Back and Stroop tests) to investigate within and between group differences. Pre and post neurophysiological (Electroencephalogram) results showed that bilateral tDCS stimulation activates cortical regions responsible for executive functions including updation (working memory) and inhibition (interference control or attention). Multiple sessions of bilateral tDCS stimulation results in a significant increase in theta, alpha, and beta-band activity in the DLPFC, cingulate and parietal cortex. This study provides evidence that tDCS can be used for performance enhancement of executive functions in able-bodied people.

Effect of Repetitive Transcranial Magnetic Stimulation on Post-stroke Dysphagia in Acute Stage.

Repetitive transcranial magnetic stimulation (rTMS) play a important role for rehabilitation in stroke. But therapeutic schedule of rTMS in dysphagia after acute stroke is still controversial. The purpose of this study was to investigate the therapeutic effect of rTMS with different frequencies on dysphagia after acute stroke. From August 2019 to December 2020, 45 patients with post-stroke dysphagia were selected as research subjects, and randomly divided into 3 groups: the high frequency stimulation on bilateral hemisphere group (High group), bilateral high frequency stimulation on the affected hemisphere and low frequency stimulation on the unaffected hemisphere group (High-low group), and sham stimulation group (Sham group). On the basis of routine swallowing training (30min) for all patients, the high group received 5Hz rTMS in both hemispheres, the high- low group received 5Hz rTMS in the unaffected hemisphere, 1Hz rTMS in the affected hemisphere, and the sham stimulation group received sham stimulation in bilateral hemisphere. All participants were assessed with dysphagia handicap index (DHI), functional oral intake scale (FOIS) and videofluoroscopic swallowing study (VFSS) before the intervention (T1), immediately after intervention (T2) and 1month after the intervention (T3). Meanwhile, according to the results of VFSS, Rosenbek penetration aspiration scale (PAS), the moving distance of hyoid bone towards the superior side (H), and pharyngeal response time (T) were analyzed and evaluated. After intervention, all three groups showed significant improvement in post-treatment scores from baseline (P = 0.000). The results of DHI, PAS and H showed that the improvement in high group and high-low group was significantly greater than sham group (P = 0.000). The results of FOIS and T showed that the improvement of bilateral high-frequency group was significantly greater than that of high-low group and sham group (P = 0.000), and the difference lasted until 1month after the end of treatment. Therefore, bilateral pharyngeal cortex high frequency rTMS and affected side high frequency/unaffected side low frequency rTMS can effectively improve swallowing disorder after acute stroke. However, the effect of bilateral high frequency rTMS is significantly higher than high-low in improving oral feeding function and pharyngeal response time.

Dual-Brain Psychology: A novel theory and treatment based on cerebral laterality and psychopathology

Dual-Brain Psychology is a theory and its clinical applications that come out of the author's clinical observations and from the Split-brain Studies. The theory posits, based on decades of rigorous, peer-reviewed experiments and clinical reports, that, in most patients, one brain's cerebral hemisphere (either left or right) when stimulated by simple lateral visual field stimulation, or unilateral transcranial photobiomodulation, reveals a dramatic change in personality such that stimulating one hemisphere evokes, as a trait, a personality that is more childlike and more presently affected by childhood maltreatments that are usually not presently appreciated but are the proximal cause of the patient's symptoms. The personality associated with the other hemisphere is much more mature, less affected by the traumas, and less symptomatic. The theory can be applied to in-depth psychotherapy in which the focus is on helping the troubled side to bear and process the traumas with the help of the therapist and the healthier personality. A person's symptoms can be evoked to aid the psychotherapy with hemispheric stimulation and the relationship between the dual personalities can be transformed from conflicted and sabotaging to cooperating toward overall health. Stimulating the positive hemisphere in most therapy patients rapidly relieves symptoms such as anxiety, depression, or substance cravings. Two randomized controlled trials used unilateral transcranial photobiomodulation to the positive hemisphere as a stand-alone treatment for opioid cravings and both revealed high effect sizes. The theory is supported by brain imaging and rTMS studies. It is the first psychological theory and application that comes out of and is supported by rigorous peer-reviewed experimentation.

Ventrolateral Prefrontal Cortex Contributes to Human Motor Learning.

This study assesses the involvement in human motor learning, of the ventrolateral prefrontal cortex (BA 9/46v), a somatic region in the middle frontal gyrus. The potential involvement of this cortical area in motor learning is suggested by studies in nonhuman primates which have found anatomic connections between this area and sensorimotor regions in frontal and parietal cortex, and also with basal ganglia output zones. It is likewise suggested by electrophysiological studies which have shown that activity in this region is implicated in somatic sensory memory and is also influenced by reward. We directly tested the hypothesis that area 9/46v is involved in reinforcement-based motor learning in humans. Participants performed reaching movements to a hidden target and received positive feedback when successful. Before the learning task, we applied continuous theta burst stimulation (cTBS) to disrupt activity in 9/46v in the left or right hemisphere. A control group received sham cTBS. The data showed that cTBS to left 9/46v almost entirely eliminated motor learning, whereas learning was not different from sham stimulation when cTBS was applied to the same zone in the right hemisphere. Additional analyses showed that the basic reward-history-dependent pattern of movements was preserved but more variable following left hemisphere stimulation, which suggests an overall deficit in somatic memory for target location or target directed movement rather than reward processing per se. The results indicate that area 9/46v is part of the human motor learning circuit.

Parietal but not temporoparietal alpha-tACS modulates endogenous visuospatial attention

Visuospatial attention can either be voluntarily directed (endogenous/top-down attention) or automatically triggered (exogenous/bottom-up attention). Recent research showed that dorsal parietal transcranial alternating current stimulation (tACS) at alpha frequency modulates the spatial attentional bias in an endogenous but not in an exogenous visuospatial attention task. Yet, the reason for this task-specificity remains unexplored. Here, we tested whether this dissociation relates to the proposed differential role of the dorsal attention network (DAN) and ventral attention network (VAN) in endogenous and exogenous attention processes respectively. To that aim, we targeted the left and right dorsal parietal node of the DAN, as well as the left and right ventral temporoparietal node of the VAN using tACS at the individual alpha frequency. Every participant completed all four stimulation conditions and a sham condition in five separate sessions. During tACS, we assessed the behavioral visuospatial attention bias via an endogenous and exogenous visuospatial attention task. Additionally, we measured offline alpha power immediately before and after tACS using electroencephalography (EEG). The behavioral data revealed an effect of tACS on the endogenous but not exogenous attention bias, with a greater leftward bias during (sham-corrected) left than right hemispheric stimulation. In line with our hypothesis, this effect was brain area-specific, i.e., present for dorsal parietal but not ventral temporoparietal tACS. However, contrary to our expectations, there was no effect of ventral temporoparietal tACS on the exogenous visuospatial attention bias. Hence, no double dissociation between the two targeted attention networks. There was no effect of either tACS condition on offline alpha power. Our behavioral data reveal that dorsal parietal but not ventral temporoparietal alpha oscillations steer endogenous visuospatial attention. This brain-area specific tACS effect matches the previously proposed dissociation between the DAN and VAN and, by showing that the spatial attention bias effect does not generalize to any lateral posterior tACS montage, renders lateral cutaneous and retinal effects for the spatial attention bias in the dorsal parietal condition unlikely. Yet the absence of tACS effects on the exogenous attention task suggests that ventral temporoparietal alpha oscillations are not functionally relevant for exogenous visuospatial attention. We discuss the potential implications of this finding in the context of an emerging theory on the role of the ventral temporoparietal node.

SPORTS AND MOVEMENTTHERAPY FOR PATIENTS WITH TRAUMATIC EXPERIENCE

— Relevance: Sport and movement therapies are indicated for patients of practically all specialties and can be defined as follows: the therapy is based on biological laws and comprises the elements of educational, psychological and social therapy methods and aimed at raising the patent’s competence in preserving health. This paper deals with a novel method for treatment and rehabilitation of a number of diseases — boxing therapy. Aim: The paper provides evidence for effectiveness of using boxing therapy at such conditions as: burnout syndrome/stress, emotionally unstable personality disorder, depression, addictive disorders, anger, explosive personality disorder, Alzheimer's disease, Parkinson's disease and other conditions. Results: There is medical evidence for positive outcomes due to use of boxing therapy for such conditions as: perceptual disorders, anxiety, burnout syndrome/stress, listlessness, depression, addictive disorders, bilateral hemispheric stimulation for processing experiences of violence, increasing frustration tolerance, improvement of stamina, inner tension, for people with traumatic experiences. Positive experiences are observed: – With patients in forensic psychiatry, – Patients with depression; – Patients with borderline personality disorder; – as an anti-aggression training with adolescents, etc. Contraindications of the boxing therapy are: – Bipolar disorder in the manic phase – Borderliner, self-injured, questionable... – Eating disorders, anorexia, bulimia questionable... – Osteoporosis – Rheumatic diseases in acute phases Conclusion: 1. Boxing therapy unites both physical and psychological training. Boxing therapy noticeably boosts and strengthens movement coordination, cognitive, motor and concentration functions, enables a better command over the body. 2. Further studies on the effectiveness of boxing therapy are required. 3. Boxing therapy should be widely used for such conditions where its effectiveness is substantiated. 4. Specialists for work as box therapists should be trained.

Thalamic Deep Brain Stimulation Ameliorates Mixed and Abductor Spasmodic Dysphonia: Case Reports and Proof of Concept

Abstract BACKGROUND AND IMPORTANCE Spasmodic dysphonia (SD) is a dystonia of the vocal folds causing difficulty with speech. A recent randomized controlled trial showed that thalamic deep brain stimulation (DBS) was safe and could improve this condition in the most common subtype—adductor SD. We investigated if thalamic DBS could also improve the other subtypes of abductor SD and mixed SD. These prospective blinded trials of 1 were designed to assess the safety of thalamic DBS in mixed and abductor SD and to quantify the magnitude of any benefit from unilateral or bilateral thalamic stimulation. CLINICAL PRESENTATION One patient with mixed SD and one patient with abductor SD received bilateral thalamic DBS. After optimizing their DBS settings for vocal improvement, they were blinded and prospectively randomized to receive 1 mo of left, right, both, or neither hemisphere stimulation. Outcome was assessed by a speech language pathologist, blinded to the settings, rating voice recordings with the Unified Spasmodic Dysphonia Rating Scale, and by patient self-reported quality-of-life questionnaires. Additional outcomes included scores of mood and cognition. There were no complications. Both patients reported a subjective improvement of their voice and quality of life with blinded left thalamic DBS. The quality of their voice was also objectively rated as improved with blinded left thalamic DBS. CONCLUSION This small proof-of-concept study suggests that left thalamic DBS can improve the quality of voice and quality of life of patients with mixed SD and abductor SD.

In Reply: Contact Location and Neuropsychological Outcomes in Subthalamic Deep Brain Stimulation

BACKGROUND A host of influences contribute to cognitive and behavioral changes following deep brain stimulation. The location of the active cathode is likely an important variable but it has received little attention. OBJECTIVE To determine whether active contact location relative to the subthalamic nucleus and other neighboring structures is related to nonmotor outcomes. METHODS We identified a retrospective, cross-sectional sample of 46 patients who underwent subthalamic nucleus deep brain stimulation for treatment of idiopathic Parkinson's disease. T-tests or nonparametric equivalents were used to detect baseline differences between unilateral left, unilateral right, and bilateral surgical groups. Correlation and partial correlational analyses identified relationships between contact location variables and alterations in cognitive, mood, quality of life, motor, and disease variables. RESULTS Medial contact locations within the left subthalamic nucleus were correlated with improvements in self-reported mood (r12 = -0.78, P = .001; 95% confidence interval [CI] = -0.43 to -0.93) but worsening semantic fluency (r26 = -0.38, P = .048; 95% CI = -0.01 to -0.66). Phonemic fluency worsened with more posterior left placement (r34 = 0.35, P = .036; 95% CI = 0.03 to 0.61). Memory outcome was related to right hemisphere stimulation voltage (r29 = -0.40, P = .022; 95% CI = -0.05 to -0.66), which is likely a proxy for variable electrode location. CONCLUSION Location of the active contact is related to nonmotor outcomes, even in electrodes that are adequately placed. This is relevant to clinical care as there appears to be a trade-off between mood and fluency abilities that should be considered during surgical planning according to preoperative patient characteristics.

Implicit Motor Imagery and the Lateral Occipitotemporal Cortex: Hints for Tailoring Non-Invasive Brain Stimulation.

Background: Recent evidence has converged in showing that the lateral occipitotemporal cortex is over-recruited during implicit motor imagery in elderly and in patients with neurodegenerative disorders, such as Parkinson’s disease. These data suggest that when automatically imaging movements, individuals exploit neural resources in the visual areas to compensate for the decline in activating motor representations. Thus, the occipitotemporal cortex could represent a cortical target of non-invasive brain stimulation combined with cognitive training to enhance motor imagery performance. Here, we aimed at shedding light on the role of the left and right lateral occipitotemporal cortex in implicit motor imagery. Methods: We applied online, high-frequency, repetitive transcranial magnetic stimulation (rTMS) over the left and right lateral occipitotemporal cortex while healthy right-handers judged the laterality of hand images. Results: With respect to the sham condition, left hemisphere stimulation specifically reduced accuracy in judging the laterality of right-hand images. Instead, the hallmark of motor simulation, i.e., the biomechanical effect, was never influenced by rTMS. Conclusions: The lateral occipitotemporal cortex seems to be involved in mental representation of the dominant hand, at least in right-handers, but not in reactivating sensorimotor information during simulation. These findings provide useful hints for developing combined brain stimulation and behavioural trainings to improve motor imagery.

Design of coils for lateralized TMS on mice

Objective. Translational studies on animals play a vital role in the advancement of transcranial magnetic stimulation (TMS) as clinical technique. Nonetheless the relevance of these procedures is frequently limited by the lack of TMS systems specifically designed for small animals capable of producing comparable stimulation conditions to those found in human TMS. In this work, we propose to take advantage of the versatility of recently introduced TMS coil design methods to produce optimal rodent-specific TMS stimulators. Approach. A stream function inverse boundary element method (IBEM) has been used for producing three small sized mice-specific TMS coils of different geometries. They have been created for unilateral hemispheric stimulation of the rodent brain, and several constraints have been considered in the design process to satisfy essential performance requirements, such as minimum stored magnetic energy, minimum power dissipation, optimised maximum current density or minimization of the undesired electric field induced in non-target regions. In order to validate the presented strategy, three prototype coils have been built. The performance of each prototype has also been numerically investigated, where the electric field induced in a mouse model has been found by using an existing computational forward technique. Main results. Stream function IBEM represents an ideally suited approach for designing specific TMS coils for small animals, capable of fulfilling many essential functional and technical requirements. The prototypes produced in this work focally stimulate the right hemisphere of the mouse brain, and so they can be successfully used in lateralized TMS experiments. Significance. The design scheme proposed here can be used to produce efficient TMS stimulators for small animals, which can overcome some of the existing limitations found when producing more reliable translational experiments.

The Effect of Electric Field on the Human Brain

Electroconvulsive therapy (ECT) is the oldest and the most effective among these modalities and utilizes electric stimulation to induce seizure activity. Recent longitudinal neuroimaging studies have demonstrated medial temporal lobe volumetric changes ipsilateral to hemispheric stimulation. These results suggest differential effects of electric stimulation (lateralized) and seizure activity (generalized).

Multifocal transcranial stimulation in chronic ischemic stroke: A phase 1/2a randomized trial

Background and PurposeRepetitive transcranial magnetic stimulation (rTMS) may promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. The objective of this study was to examine whether multifocal cortical stimulation using a new wearable transcranial rotating permanent magnet stimulator (TRPMS) can promote recovery of motor function after stroke by inducing functional reorganization of cortical circuits. MethodsThirty30 patients with chronic ischemic stroke and stable unilateral weakness were enrolled in a Phase 1/2a randomized double-blind sham-controlled clinical trial to evaluate safety and preliminary efficacy. Bilateral hemispheric stimulation was administered for 20 sessions 40 min each over 4 weeks. The primary efficacy endpoint was the change in functional MRI BOLD activation immediately after end of treatment. Secondary efficacy endpoints were clinical scales of motor function, including the Fugl-Meyer motor arm score, ARAT, grip strength, pinch strength, gait velocity, and NIHSS. ResultsTRPMS treatment was well-tolerated with no device-related adverse effects. Active treatment produced a significantly greater increase in the number of active voxels on fMRI than sham treatment (median +48.5 vs -30, p = 0.038). The median active voxel number after active treatment was 8.8-fold greater than after sham (227.5 vs 26, p = 0.016). Although the statistical power was inadequate to establish clinical endpoint benefits, numerical improvements were demonstrated in 5 of 6 clinical scales of motor function. The treatment effects persisted over a 3-month duration of follow-up. ConclusionsMultifocal bilateral TRPMS was safe and showed significant fMRI changes suggestive of functional reorganization of cortical circuits in patients with chronic ischemic stroke. A larger randomized clinical trial is warranted to verify recovery of motor function.

Abstract WP310: PRIMED Preclinical Evidence Scoring Tool to Assess Readiness for Translation of Neuroprotection Therapies

Introduction: Multiple neuroprotective therapies (NPT’s) for treatment of acute ischemic stroke have failed in translation to human studies, indicating a need for more rigorous quality assessment of all the cumulative preclinical evidence supporting an NPT prior to conducting human trials. There is a need for an updated translational readiness assessment tool to assess candidate therapies that combines desirable elements of existing instruments (STAIR 2.0, CAMARADES, RoB2) and include additional important elements. Methods: Candidate items for the intervention translational readiness scale, based on prior instruments, were rated by importance, reliability, and feasibility. For illustrative purposes, the assessment tool was applied to four NPT in current development, including two pharmacologic agents [uric acid (UA) and trans sodium crocetinate (TSC)] and two neuromodulatory device interventions [cathodal direct current stimulation (C-DCS) of ischemic hemisphere and fastigial nucleus stimulation (FSN)]. Results: The final Preclinical evidence of Readiness In stroke Models Evaluating Drugs/Devices (PRIMED) assessment tool rates evidence available from all reported animal studies in 10 domains (Fig1). Among the four assessed candidate NPT’s, the scores for two pharmacologic NPT’s indicated high translational readiness (UA and TSC 17) and the two neuromodulatory NPT’s had intermediate readiness-for-translation (C-DCS 12, FNS 8). Conclusion: The PRIMED assessment tool is an updated, multidimensional tool that provides a detailed assessment of multiple important readiness features across all preclinical experiments testing an NPT to assess readiness for translation, applicable to both pharmocologic and device therapies for acute stroke, providing both qualitative profiling of agent strengths and weaknesses and a quantitative summary score. Based on this tool, translational readiness is high for UA and TSC and intermediate for C-DCS and FNS.

Perception of Rhythmic Speech Is Modulated by Focal Bilateral Transcranial Alternating Current Stimulation.

Several recent studies have used transcranial alternating current stimulation (tACS) to demonstrate a causal role of neural oscillatory activity in speech processing. In particular, it has been shown that the ability to understand speech in a multi-speaker scenario or background noise depends on the timing of speech presentation relative to simultaneously applied tACS. However, it is possible that tACS did not change actual speech perception but rather auditory stream segregation. In this study, we tested whether the phase relation between tACS and the rhythm of degraded words, presented in silence, modulates word report accuracy. We found strong evidence for a tACS-induced modulation of speech perception, but only if the stimulation was applied bilaterally using ring electrodes (not for unilateral left hemisphere stimulation with square electrodes). These results were only obtained when data were analyzed using a statistical approach that was identified as optimal in a previous simulation study. The effect was driven by a phasic disruption of word report scores. Our results suggest a causal role of neural entrainment for speech perception and emphasize the importance of optimizing stimulation protocols and statistical approaches for brain stimulation research.