Motor cortex activation by H-coil and figure-8 coil at different depths. Combined motor threshold and electric field distribution study

Clinical efficacy of deep transcranial magnetic stimulation (dTMS) in psychiatric and cognitive disorders: A systematic review

Deep transcranial magnetic stimulation (dTMS) has gained attention as an enhanced form of traditional TMS, targeting broader and deeper regions of the brain. However, a fulsome synthesis of dTMS efficacy across psychiatric and cognitive disorders using sham-controlled trials is lacking. We systematically reviewed 28 clinical trials comparing active dTMS to a sham/controlled condition to characterize dTMS efficacy across diverse psychiatric and cognitive disorders. A comprehensive search of APA PsycINFO, Cochrane, Embase, Medline, and PubMed databases was conducted. Predominant evidence supports dTMS efficacy in patients with obsessive-compulsive disorder (OCD; n = 2), substance use disorders (SUDs; n = 8), and in those experiencing depressive episodes with major depressive disorder (MDD) or bipolar disorder (BD; n = 6). However, the clinical efficacy of dTMS in psychiatric disorders characterized by hyperactivity or hyperarousal (i.e., attention-deficit/hyperactivity disorder, posttraumatic stress disorder, and schizophrenia) was heterogeneous. Common side effects included headaches and pain/discomfort, with rare but serious adverse events such as seizures and suicidal ideation/attempts. Risk of bias ratings indicated a collectively low risk according to the Grading of Recommendations, Assessment, Development, and Evaluations checklist (Meader et al., 2014). Literature suggests promise for dTMS as a beneficial alternative or add-on treatment for patients who do not respond well to traditional treatment, particularly for depressive episodes, OCD, and SUDs. Mixed evidence and limited clinical trials for other psychiatric and cognitive disorders suggest more extensive research is warranted. Future research should examine the durability of dTMS interventions and identify moderators of clinical efficacy.

Synergistic use of deep TMS therapy with IV ketamine infusions for major depressive disorder: a pilot study

OBJECTIVE

Major Depressive Disorder (MDD) is a pervasive psychiatric condition effecting approximately 21 million adults in the U.S. (8.4%). An estimated 30-60% of patients are resistant to traditional treatment approaches (medications and talk-therapy), alluding to the need for additional options. Two promising treatment modalities include transcranial magnetic stimulation (TMS) and ketamine infusions; both have shown efficacy in standalone studies but have scarcely been investigated synergistically in the same group of participants.

METHOD

In the current study, 169 participants with treatment-resistant MDD received 36 treatments of Deep TMS-only (H1 + H7 protocols), while 66 received 36 treatments of Deep TMS (H1 + H7 protocols) and 6 IV infusions of ketamine over the course of 9 weeks. Depressive symptoms were compared pre- and -post treatment in both conditions using the PHQ-9.

RESULTS

In both treatment groups, depressive symptoms were significantly reduced from pre-to-post and there were no significant differences in response between the TMS + ketamine condition and the TMS-only condition. The TMS + ketamine condition had an 80.30% response rate (53 out of 66) and 43.42% remission rate (28 out of 66) compared to a 76.92% response (130 out of 169) and 39.64% remission (67 out of 16) in the TMS-only condition.

CONCLUSION

These results support the notion that TMS treatments yield high response rates in treatment-resistant cases; however, in this investigation there was no added benefit for including 6 sessions of IV ketamine in conjunction with TMS. Future investigations using randomized-control designs and robust outcome measures are warranted.

Comparison of the analgesic effects of "superficial" and "deep" repetitive transcranial magnetic stimulation in patients with central neuropathic pain: a randomized sham-controlled multicenter international crossover study

ABSTRACT

We directly compared the analgesic effects of "superficial" and 'deep" repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex in patients with central neuropathic pain. Fifty-nine consecutive patients were randomly assigned to active or sham "superficial" (using a figure-of-8 [F8]-coil) or "deep" (using a Hesed [H]-coil) stimulation according to a double-blind crossover design. Each treatment period consisted of 5 daily stimulation sessions and 2 follow-up visits at 1 and 3 weeks after the last stimulation session. The primary outcome was the comparison of the mean change in average pain intensity over the course of the treatment (group × time interaction). Secondary outcomes included neuropathic symptoms (NPSI), pain interference, patient global impression of change (PGIC), anxiety, depression, and catastrophizing. In total, 51 patients participated in at least one session of both treatments. There was a significant interaction between "treatment" and "time" (F = 2.7; P = 0.0024), indicating that both figure-8 (F8-coil) and H-coil active stimulation induced significantly higher analgesic effects than sham stimulation. The analgesic effects of both types of coils had a similar magnitude but were only moderately correlated ( r = 0.39, P = 0.02). The effects of F8-coil stimulation appeared earlier, whereas the effects of H-coil stimulation were delayed, but tended to last longer (up to 3 weeks) as regards to several secondary outcomes (PGIC and total NPSI score). In conclusion, "deep" and "superficial" rTMS induced analgesic effects of similar magnitude in patients with central pain, which may involve different mechanisms of action.

Applying transcranial magnetic stimulation to rehabilitation of poststroke lower extremity function and an improvement: Individual-target TMS

Stroke is the leading cause of disability globally in need of novel and effective methods of rehabilitation. Intermittent theta burst stimulation (iTBS) has been adopted as a Level B recommendation for lower limb spasticity in guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS). Nonetheless, the methodological differences and deficits of existing work bring about heterogenous results and therefore limit the universal clinical use of rTMS in lower extremity (LE) rehabilitation. The variation of stimulated targets across motor cortex contributes mainly to these heterogeneities. This narrative review includes studies of rTMS on LE motor function rehabilitation in patients after stroke until now. Some analyses of brain imaging and electromagnetic simulation and quantification through computational modeling were also performed. rTMS appears capable of fostering LE motor rehabilitation after stroke, but the actually stimulated targets are considerably bias making it difficult to confirm effectiveness. The main reason for this phenomenon is probably inaccurate targeting of motor cortical leg representation. An underlying updated method is proposed as Individual-Target TMS (IT-TMS) combined with brain imaging. rTMS is a promising validated method for LE function regaining. Future studies should systematically compare the effects of IT-TMS with traditional rTMS using large samples in random clinical trials. This article is categorized under: Neuroscience > Clinical Neuroscience.

Revisiting the Rotational Field TMS Method for Neurostimulation

Transcranial magnetic stimulation (TMS) is a non-invasive technique that has shown high efficacy in the treatment of major depressive disorder (MDD) and is increasingly utilized for various neuropsychiatric disorders. However, conventional TMS is limited to activating only a small fraction of neurons that have components parallel to the induced electric field. This likely contributes to the significant variability observed in clinical outcomes. A novel method termed rotational field TMS (rfTMS or TMS 360°) enables the activation of a greater number of neurons by reducing the sensitivity to orientation. Recruitment of a larger number of neurons offers the potential to enhance efficacy and reduce variability in the treatment of clinical indications for which neuronal recruitment and organization may play a significant role, such as MDD and stroke. The potential of the method remains to be validated in clinical trials. Here, we revisit and describe in detail the rfTMS method, its principles, mode of operation, effects on the brain, and potential benefits for clinical TMS.

Detailed measurements and simulations of electric field distribution of two TMS coils cleared for obsessive compulsive disorder in the brain and in specific regions associated with OCD

The FDA cleared deep transcranial magnetic stimulation (Deep TMS) with the H7 coil for obsessive-compulsive disorder (OCD) treatment, following a double-blinded placebo-controlled multicenter trial. Two years later the FDA cleared TMS with the D-B80 coil on the basis of substantial equivalence. In order to investigate the induced electric field characteristics of the two coils, these were placed at the treatment position for OCD over the prefrontal cortex of a head phantom, and the field distribution was measured. Additionally, numerical simulations were performed in eight Population Head Model repository models with two sets of conductivity values and three Virtual Population anatomical head models and their homogeneous versions. The H7 was found to induce significantly higher maximal electric fields (p<0.0001, t = 11.08) and to stimulate two to five times larger volumes in the brain (p<0.0001, t = 6.71). The rate of decay of electric field with distance is significantly slower for the H7 coil (p < 0.0001, Wilcoxon matched-pairs test). The field at the scalp is 306% of the field at a 3 cm depth with the D-B80, and 155% with the H7 coil. The H7 induces significantly higher intensities in broader volumes within the brain and in specific brain regions known to be implicated in OCD (dorsal anterior cingulate cortex (dACC), dorsolateral prefrontal cortex (dlPFC), inferior frontal gyrus (IFG), orbitofrontal cortex (OFC) and pre-supplementary motor area (pre-SMA)) compared to the D-B80. Significant field ≥ 80 V/m is induced by the H7 (D-B80) in 15% (1%) of the dACC, 78% (29%) of the pre-SMA, 50% (20%) of the dlPFC, 30% (12%) of the OFC and 15% (1%) of the IFG. Considering the substantial differences between the two coils, the clinical efficacy in OCD should be tested and verified separately for each coil.

Repetitive Transcranial Magnetic Stimulation in Alcohol Dependence: A Randomized, Double-Blind, Sham-Controlled Proof-of-Concept Trial Targeting the Medial Prefrontal and Anterior Cingulate Cortices

BACKGROUND

Alcohol addiction is associated with a high disease burden, and treatment options are limited. In a proof-of-concept study, we used deep repetitive transcranial magnetic stimulation (dTMS) to target circuitry associated with the pathophysiology of alcohol addiction. We evaluated clinical outcomes and explored associated neural signatures using functional magnetic resonance imaging.

METHODS

This was a double-blind, randomized, sham-controlled trial. A total of 51 recently abstinent treatment-seeking patients with alcohol use disorder (moderate to severe) were randomized to sham or active dTMS, using an H7 coil targeting midline frontocortical areas, including the medial prefrontal and anterior cingulate cortices. Treatment included 15 sessions over 3 weeks, followed by five sessions over 3 months of follow-up. Each session delivered 100 trains of 30 pulses at 10 Hz. The primary predefined outcome was reduction in percentage of heavy drinking days, obtained using timeline follow-back interviews. Secondary analyses included self-reports of craving, ethyl glucuronide in urine, and brain imaging measures.

RESULTS

Both craving after treatment and percentage of heavy drinking days during follow-up were significantly lower in the active versus sham control group (percentage of heavy drinking days = 2.9 ± 0.8% vs. 10.6 ± 1.9%, p = .037). Active dTMS was associated with decreased resting-state functional connectivity of the dorsal anterior cingulate cortex with the caudate nucleus and decreased connectivity of the medial prefrontal cortex to the subgenual anterior cingulate cortex.

CONCLUSIONS

We provide initial proof-of-concept for dTMS targeting midline frontocortical structures as a treatment for alcohol addiction. These data strongly support a rationale for a full-scale confirmatory multicenter trial. Therapeutic benefits of dTMS appear to be associated with persistent changes in brain network activity.

Electric Field Distribution Induced by TMS: Differences Due to Anatomical Variation

Transcranial magnetic stimulation (TMS) is a well-established technique for the diagnosis and treatment of neuropsychiatric diseases. The numerical calculation of the induced electric field (EF) distribution in the brain increases the efficacy of stimulation and improves clinical outcomes. However, unique anatomical features, which distinguish each subject, suggest that personalized models should be preferentially used. The objective of the present study was to assess how anatomy affects the EF distribution and to determine to what extent personalized models are useful for clinical studies. The head models of nineteen healthy volunteers were automatically segmented. Two versions of each head model, a homogeneous and a five-tissue anatomical, were stimulated by the model of a Hesed coil (H-coil), employing magnetic quasi-static simulations. The H-coil was placed at two standard stimulating positions per model, over the frontal and central areas. The results show small, but indisputable, variations in the EFs for the homogeneous and anatomical models. The interquartile ranges in the anatomical versions were higher compared to the homogeneous ones, indicating that individual anatomical features may affect the prediction of stimulation volumes. It is concluded that personalized models provide complementary information and should be preferably employed in the context of diagnostic and therapeutic TMS studies.

Optimal Design of Transcranial Magnetic Stimulation Coil with Iron Core

OBJECTIVE

Iron core coils offer a passive way to increase the induced electric field intensity during transcranial magnetic stimulation (TMS), but the influences of core position and dimensions on coil performance have not been elaborately discussed before.

APPROACH

In this study, with the basic figure-of-eight (Fo8) and slinky coil structures, iron core coil optimization is performed with the finite element method considering core position and dimensions. A performance factor combining performance parameters, including the maximum induced electric field, stimulation depth, focus, and heat loss, is utilized to evaluate the comprehensive coil performance.

MAIN RESULTS

According to the performance factor, both iron core coils obtain the best overall performance with a fill factor 0.4 and the two legs of the iron core close to the inner sides of the coil. Finally, three prototypes are constructed-the basic, optimized, and full-size slinky iron core coil-and magnetic field detection demonstrates a good agreement with the simulation results.

SIGNIFICANCE

The proposed systematic optimization approach for iron core coil based on Fo8 and slinky basic structure can be applied to improve TMS coil performance, reduce power requirements, and guide the design of other iron core TMS coils.

Neurostimulation for the treatment of functional neurological disorder: A systematic review

Functional Neurological Disorder (FND), also known as conversion disorder, is characterized by neurological symptoms that are incompatible with any known structural disorder and best explained by a biopsychosocial model. Evidence-based treatments for FND are limited, with cognitive behavioral therapy (CBT) and physiotherapy being the most effective interventions [1]. In recent years, functional neuroimaging studies have provided robust evidence of alterations in activity and connectivity in multiple brain networks in FND. This body of evidence suggests that neurocircuitry-based interventions, such as non-invasive brain stimulation techniques (NIBS), may also represent an effective therapeutic option for patients with FND. In this systematic review, we outline the current state of knowledge of NIBS in FND, and discuss limitations and future directions that may help establish the efficacy of NIBS as a therapeutic option for FND.

Exploratory study of optimal parameters of repetitive transcranial magnetic stimulation for neuropathic pain in the lower extremities

Introduction

Pain relief from repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) is particularly poor in patients with leg pain. The optimal parameters for relieving leg pain remain poorly understood. The purpose of this study was to explore the optimal stimulation parameters of M1-rTMS for patients with leg pain.

Methods

Eleven patients with neuropathic pain in the leg randomly underwent 6 conditions of M1-rTMS with different stimulation intensities, sites, and coil directions, including sham stimulation. The 5 active conditions were as follows: 90% or 110% of the resting motor threshold (RMT) on the M1 hand with an anteroposterior coil direction, 90% or 110% RMT on the M1 foot in the anteroposterior direction, and 90% RMT on the M1 foot in the mediolateral direction. Each condition was administered for 3 days. Pain intensity was evaluated using the Visual Analogue Scale and Short-Form McGill Pain Questionnaire 2 at baseline and up to 7 days after each intervention.

Results

Visual Analogue Scale scores were significantly reduced after the following active rTMS conditions: 90% RMT on the M1 hand, 90% RMT on the M1 foot with any coil direction, and 110% RMT on the M1 foot. The Short-Form McGill Pain Questionnaire 2 results were similar to those obtained using the Visual Analogue Scale. The analgesic effect of rTMS with stimulus intensity above the RMT was not superior to that below the RMT.

Conclusion

We suggest that the optimal stimulation parameters of rTMS for patients with neuropathic pain in the leg may target the M1 foot or M1 hand with an intensity below the RMT.

Repetitive transcranial magnetic stimulation as a potential treatment approach for cannabis use disorder

The expanding legalization of cannabis across the United States is associated with increases in cannabis use, and accordingly, an increase in the number and severity of individuals with cannabis use disorder (CUD). The lack of FDA-approved pharmacotherapies and modest efficacy of psychotherapeutic interventions means that many of those who seek treatment for CUD relapse within the first few months. Consequently, there is a pressing need for innovative, evidence-based treatment development for CUD. Preliminary evidence suggests that repetitive transcranial magnetic stimulation (rTMS) may be a novel, non-invasive therapeutic neuromodulation tool for the treatment of a variety of substance use disorders (SUDs), including recently receiving FDA clearance (August 2020) for use as a smoking cessation aid in tobacco cigarette smokers. However, the potential of rTMS for CUD has not yet been reviewed. This paper provides a primer on therapeutic neuromodulation techniques for SUDs, with a particular focus on reviewing the current status of rTMS research in people who use cannabis. Lastly, future directions are proposed for rTMS treatment development in CUD, with suggestions for study design parameters and clinical endpoints based on current gold-standard practices for therapeutic neuromodulation research.

Seizure risk with repetitive TMS: Survey results from over a half-million treatment sessions

BACKGROUND

Seizures are rare during repetitive transcranial magnetic stimulation (rTMS) treatment, but estimating risk is difficult because of study heterogeneity and sampling limitations. Moreover, there are few studies comparing rates between device manufacturers.

OBJECTIVE

The objective of this study was to calculate rTMS seizure rates across various FDA-cleared devices in naturalistic clinical settings.

METHODS

In July and August 2018, approximately 500 members of the Clinical TMS Society (CTMSS) were electronically surveyed about seizures in their practices. Seizures were distinguished from non-seizures by a remote semi-structured interview with a Board-certified neurologist and Co-Chair of the CTMSS Standards Committee. Exact Poisson calculations were used to estimate seizure rates and confidence intervals across the four most widely used manufacturers.

RESULTS

The survey was completed by 134 members, with 9 responses excluded because of data inconsistencies. In total, 18 seizures were reported in 586,656 sessions and 25,526 patients across all device manufacturers. The overall seizure rate was 0.31 (95% CI: 0.18, 0.48) per 10,000 sessions, and 0.71 (95% CI: 0.42, 1.11) per 1000 patients. The Brainsway H-coil seizure rate of 5.56 per 1000 patients (95% CI: 2.77,9.95) was significantly higher (p < 0.001) than the three most widely used figure- 8 coil devices' combined seizure rate of 0.14 per 1000 patients (95% CI: 0.01, 0.51).

CONCLUSION

The absolute risk of a seizure with rTMS is low, but generic Brainsway H-coil treatment appears to be associated with a higher relative risk than generic figure- 8 coil treatment. Well-designed prospective studies are warranted to further investigate this risk.

Repetitive Transcranial Magnetic Stimulation as a Therapeutic and Probe in Schizophrenia: Examining the Role of Neuroimaging and Future Directions

Schizophrenia is a complex condition associated with perceptual disturbances, decreased motivation and affect, and disrupted cognition. Individuals living with schizophrenia may experience myriad poor outcomes, including impairment in independent living and function as well as decreased life expectancy. Though existing treatments may offer benefit, many individuals still experience treatment resistant and disabling symptoms. In light of the negative outcomes associated with schizophrenia and the limitations in currently available treatments, there is a significant need for novel therapeutic interventions. Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that can modulate the activity of discrete cortical regions, allowing direct manipulation of local brain activation and indirect manipulation of the target's associated neural networks. rTMS has been studied in schizophrenia for the treatment of auditory hallucinations, negative symptoms, and cognitive deficits, with mixed results. The field's inability to arrive at a consensus on the use rTMS in schizophrenia has stemmed from a variety of issues, perhaps most notably the significant heterogeneity amongst existing trials. In addition, it is likely that factors specific to schizophrenia, rather than the rTMS itself, have presented barriers to the interpretation of existing results. However, advances in approaches to rTMS as a biologic probe and therapeutic, many of which include the integration of neuroimaging with rTMS, offer hope that this technology may still play a role in improving the understanding and treatment of schizophrenia.

Characterizing off-target corticospinal responses to double-cone transcranial magnetic stimulation

INTRODUCTION

The double-cone coil (D-CONE) is frequently used in transcranial magnetic stimulation (TMS) experiments that target the motor cortex (M1) lower-limb representation. Anecdotal evidence and modeling studies have shed light on the off-target effects of D-CONE TMS but the physiological extent remains undetermined.

PURPOSE

To characterize the off-target effects of D-CONE TMS based on bilateral corticospinal responses in the legs and hands.

METHODS

Thirty (N = 30) participants (9 women, age: 26 ± 5yrs) completed a stimulus-response curve procedure with D-CONE TMS applied to the dominant vastus lateralis (cVL) and motor-evoked potentials (MEPs) recorded in each active VL and resting first dorsal interosseous (FDI). As a positive control (CON), the dominant FDI was directly targeted with a figure-of-eight coil and MEPs were similarly recorded in each active FDI and resting VL. MEP_MAX, V50 and MEP latencies were compared with repeated-measures ANOVAs or mixed-effects analysis and Bonferroni-corrected pairwise comparisons.

RESULTS

Off-target responses were evident in all muscles, with similar MEP_MAX in the target (cVL) and off-target (iVL) leg (p = 0.99) and cFDI compared with CON (p = 0.99). cFDI and CON MEP_MAX were greater than iFDI (p < 0.01). A main effect of target (p < 0.001) indicated that latencies were shorter with CON but similar in all muscles with D-CONE.

DISCUSSION

Concurrent MEP recordings in bilateral upper- and lower-extremity muscles confirm that lower-limb D-CONE TMS produces substantial distance-dependent off-target effects. In addition to monitoring corticospinal responses in off-target muscles to improve targeting accuracy in real-time, future studies may incorporate off-target information into statistical models post-hoc.

Prefrontal cortex circuits in depression and anxiety: contribution of discrete neuronal populations and target regions

Our understanding of depression and its treatment has advanced with the advent of ketamine as a rapid-acting antidepressant and the development and refinement of tools capable of selectively altering the activity of populations of neuronal subtypes. This work has resulted in a paradigm shift away from dysregulation of single neurotransmitter systems in depression towards circuit level abnormalities impacting function across multiple brain regions and neurotransmitter systems. Studies on the features of circuit level abnormalities demonstrate structural changes within the prefrontal cortex (PFC) and functional changes in its communication with distal brain structures. Treatments that impact the activity of brain regions, such as transcranial magnetic stimulation or rapid-acting antidepressants like ketamine, appear to reverse depression associated circuit abnormalities though the mechanisms underlying the reversal, as well as development of these abnormalities remains unclear. Recently developed optogenetic and chemogenetic tools that allow high-fidelity control of neuronal activity in preclinical models have begun to elucidate the contributions of the PFC and its circuitry to depression- and anxiety-like behavior. These tools offer unprecedented access to specific circuits and neuronal subpopulations that promise to offer a refined view of the circuit mechanisms surrounding depression and potential mechanistic targets for development and reversal of depression associated circuit abnormalities.

Repetitive Transcranial Magnetic Stimulation With H-Coil Coupled With Cycling for Improving Lower Limb Motor Function After Stroke: An Exploratory Study

BACKGROUND/OBJECTIVES

Repetitive transcranial magnetic stimulation (rTMS) has been recognized as a promising intervention for the treatment of post-stroke motor deficits. Here, we explore safety, feasibility, and potential effectiveness of high-frequency rTMS (HF-rTMS) delivered with the Hesed coil (H-coil) during active cycling on paretic lower extremity (LE) motor function in chronic stroke.

MATERIALS AND METHODS

Twelve subjects with a first-ever stroke were recruited in this double-blind, placebo controlled, crossover study. Eleven sessions of HF-rTMS (40 2s-trains of 20 Hz at 90% resting leg motor threshold) were delivered over the LE motor areas using the H-coil during active cycling for three weeks. Each subject underwent both real and sham rTMS treatments separated by a four-week washout period, in a random sequence. Vital signs were recorded before and after each rTMS session. Any discomfort related to stimulation and side effects were recorded. LE function was also evaluated with Fugl-Meyer assessment (FMA-LE), spasticity was assessed with modified-Ashworth scale and measures of gait speed and endurance (10-meter and 6-min walk tests, respectively) were recorded.

RESULTS

No participant reported serious adverse effects. During real rTMS, 4 of 12 subjects reported mild side effects including transitory dizziness and muscle twitches on shoulder, so that intensity of stimulation initially set at 90% of RMT was reduced to 80% of RMT on average in these four subjects. Only real treatment was associated with a significant and sustained improvement in FMA-LL (67% responders vs. 9% of the sham). Spasticity significantly ameliorated only after the real rTMS. Real treatment did not offer advantages on walking timed measures when compared with sham.

CONCLUSIONS

This exploratory study suggests that bilateral HF-rTMS combined with cycling is safe and potentially effective in ameliorating paretic LE motor function and spasticity, rather than gait speed or endurance, in chronic stroke.

Efficacy and tolerability of deep transcranial magnetic stimulation for treatment-resistant depression: A systematic review and meta-analysis

OBJECTIVES

This study aimed to investigate the efficacy of deep transcranial magnetic stimulation (dTMS) for treatment-resistant depression (TRD).

METHODS

This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Medline, PsycINFO, Embase, and Cochrane Library were systematically searched from the time of their inception until July 17, 2019. Data were pooled using a random-effects model. Primary outcomes were mean change of depression and anxiety severity. Secondary outcomes were response and remission rate of depression.

RESULTS

Fifteen studies including three randomized controlled trials (RCTs) (n = 417, mean age: 50.6 years) and twelve uncontrolled clinical trials (n = 284, mean age: 46.4 years) were included. dTMS significantly improved the depressive (Hedges' g = -1.323, 95% CI = -1.651 to -0.995, p < .001) and anxiety symptoms (Hedges' g = -1.282, 95% CI = -1.514 to -1.051, p < .001) in patients with TRD. Subgroup analysis showed that non-RCTs had a larger effect size than RCTs (-1.461 vs -0.756) on depression severity. Although the response and remission rates of the dTMS group were high, only studies using both dTMS and antidepressant medications achieved significance. The anxiolytic effect of dTMS was more heterogeneous, and the results were obtained mainly from non-RCTs. Importantly, the dTMS group showed favorable tolerability without major adverse events.

CONCLUSIONS

dTMS is a safe and effective intervention in patients with TRD. Studies combining dTMS and antidepressant medications seemed to show greater therapeutic effects. Future studies are needed to address the interaction effect of dTMS with different classes of antidepressant medications.

Rotational field TMS: Comparison with conventional TMS based on motor evoked potentials and thresholds in the hand and leg motor cortices

BACKGROUND

Transcranial magnetic stimulation (TMS) is a rapidly expanding technology utilized in research and neuropsychiatric treatments. Yet, conventional TMS configurations affect primarily neurons that are aligned parallel to the induced electric field by a fixed coil, making the activation orientation-specific. A novel method termed rotational field TMS (rfTMS), where two orthogonal coils are operated with a 90° phase shift, produces rotation of the electric field vector over almost a complete cycle, and may stimulate larger portion of the neuronal population within a given brain area.

OBJECTIVE

To compare the physiological effects of rfTMS and conventional unidirectional TMS (udTMS) in the motor cortex.

METHODS

Hand and leg resting motor thresholds (rMT), and motor evoked potential (MEP) amplitudes and latencies (at 120% of rMT), were measured using a dual-coil array based on the H7-coil, in 8 healthy volunteers following stimulation at different orientations of either udTMS or rfTMS.

RESULTS

For both target areas rfTMS produced significantly lower rMTs and much higher MEPs than those induced by udTMS, for comparable induced electric field amplitude. Both hand and leg rMTs were orientation-dependent.

CONCLUSIONS

rfTMS induces stronger physiologic effects in targeted brain regions at significantly lower intensities. Importantly, given the activation of a much larger population of neurons within a certain brain area, repeated application of rfTMS may induce different neuroplastic effects in neural networks, opening novel research and clinical opportunities.

Therapeutic noninvasive brain stimulation in Alzheimer's disease and related dementias

PURPOSE OF REVIEW

Alzheimer's disease is a progressive neurodegenerative disease without effective pharmacological treatment. Noninvasive brain stimulation (NIBS) techniques, such as repetitive transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES), are increasingly being investigated for their potential to ameliorate the symptoms of Alzheimer's disease and related dementias (ADRD).

RECENT FINDINGS

A comprehensive literature review for primary research reports that investigated the ability of TMS/tES to improve cognition in ADRD patients yielded a total of 20 reports since 2016. Eight studies used repetitive TMS and 12 used transcranial direct current stimulation, the most common form of tES. Eight of the studies combined NIBS with cognitive training. Promising results should encourage continued investigation, however there is currently insufficient evidence to support widespread adoption of NIBS-based clinical treatments for ADRD.

SUMMARY

NIBS remains an active area of investigation for treatment of ADRD, though the predominance of small, heterogeneous, proof-of-principle studies precludes definitive conclusions. We propose the establishment of a consortium to achieve the benefits of large-scale, controlled studies using biomarker-based diagnostic characterization of participants, development of neurophysiological markers to verify target engagement, and standardization of parameters.

Effects of Repetitive Transcranial Magnetic Stimulation on Walking and Balance Function after Stroke: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of this study was to investigate the effects of repetitive transcranial magnetic stimulation (rTMS) on walking and balance function in patients with stroke.

DESIGN

MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, CENTRAL, and the Physiotherapy Evidence Database were comprehensively searched for randomized controlled trials published through March 2017 that investigated the effects of rTMS on lower limb function. Main outcomes included walking speed, balance function, motor function, and cortical excitability.

RESULTS

Nine studies were included. The meta-analysis revealed a significant effect of rTMS on walking speed (standardized mean difference, 0.64; 95% confidence interval [CI], 0.32-0.95), particularly ipsilesional stimulation (standardized mean difference, 0.80; 95% CI, 0.36-1.24). No significant effects were found for balance function (standardized mean difference, 0.10; 95% CI, -0.26 to 0.45), motor function (mean difference, 0.50, 95% CI: -0.68 to 1.68), or cortical excitability (motor-evoked potentials of the affected hemisphere: mean difference, 0.21 mV; 95% CI, -0.11 to 0.54; motor-evoked potentials of the unaffected hemisphere: mean difference, 0.09 mV; 95% CI, -0.16 to -0.02).

CONCLUSION

These results suggest that rTMS, particularly ipsilesional stimulation, significantly improves walking speed. Future studies with larger sample sizes and an adequate follow-up period are required to further understand the effects of rTMS on lower limb function and its relationship with changes in cortical excitability with the help of functional neuroimaging techniques.

TO CLAIM CME CREDITS

Complete the self-assessment activity and evaluation online at http://www.physiatry.org/JournalCME CME OBJECTIVES: Upon completion of this article, the reader should be able to: 1) Understand the potential neurophysiologic effects of rTMS; 2) Appreciate the potential benefits of rTMS on stroke recovery; and 3) Identify indications for including rTMS in a stroke rehabilitation program.

LEVEL

Advanced ACCREDITATION: The Association of Academic Physiatrists is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians.The Association of Academic Physiatrists designates this Journal-based CME activity for a maximum of 1.0 AMA PRA Category 1 Credit(s)™. Physicians should only claim credit commensurate with the extent of their participation in the activity.

An Update on Repetitive Transcranial Magnetic Stimulation for the Treatment of Major Depressive Disorder

Repetitive transcranial magnetic stimulation (rTMS) has emerged as an evidenced-based treatment for major depression that does not respond to standard first-line therapies. The majority of data support the use of high-frequency (10 Hz) treatment delivered to the left dorsolateral prefrontal cortex. Intermittent theta burst stimulation is a new emerging treatment that reduces the time required to deliver treatment and can increase capacity and access to this treatment. This review will comprehensively cover recent advancements in the field of rTMS for depression, including stimulation parameters and targets aimed at enhancing outcomes. In addition, efforts to use modern neuroscience tools to personalize this treatment and optimize outcomes will be reviewed.

Antidepressant outcomes of high-frequency repetitive transcranial magnetic stimulation (rTMS) with F8-coil and deep transcranial magnetic stimulation (DTMS) with H1-coil in major depression: a systematic review and meta-analysis

BACKGROUND

The current study aims to systematically assess and compare the antidepressant outcomes of repetitive transcranial magnetic stimulation (rTMS) with the figure-of-eight (F8)-coil and deep transcranial magnetic stimulation (DTMS) with the H1-coil in studies matched on stimulation frequency in unipolar major depressive disorder (MDD).

METHODS

Electronic search of Medline and PsycInfo identified 19 studies with stimulation frequency of 18-20 Hz using F8-coil (k = 8 randomised sham-controlled trials, RCTs, k = 3 open-label; n = 168 patients) or H1-coil (k = 1 RCT, k = 7 open-label; n = 200). Depression severity (the primary outcome) and response/remission rates (the secondary outcomes) were assessed at session 10.

RESULTS

Effects pooled with random-effects meta-analysis showed a large reduction in depression severity, 29% response, and 15% remission rates after 10 sessions of active stimulation with either coil relative to baseline. Reduction in depression severity was greater in studies with younger patients using either coil. The comparison between coils showed a larger reduction in depression severity in H1-coil vs. F8-coil studies (independent of the study design or the concurrent pharmacotherapy) and a trend towards higher remission rates in F8-coil vs. H1-coils studies. These effects are based on a low volume of studies, are not controlled for placebo, and may not be clinically-relevant. The stimulation protocols differed systematically because stimulation was more focal but less intense (80-110% of the resting motor threshold, MT) in the F8-coil studies and less focal but more intense (120% MT) in the H1-coil studies. Two seizures occurred in the H1-coil studies relative to none in the F8-coil studies.

CONCLUSION

When matched on frequency, the higher-intensity and less focal stimulation with the H1-coil reduces depression more than the lower-intensity and more focal stimulation with the F8-coil. Head-to-head trials should compare the antidepressant outcomes of F8-coil and H1-coil to identify the most optimal stimulation protocols for acute and longer-lasting efficacy.

Noninvasive Transcranial Magnetic Brain Stimulation in Stroke

It is likely that transcranial magnetic brain stimulation will be used for the clinical treatment of stroke and stroke-related impairments in the future. The anatomic target and stimulation parameters will likely vary for any clinical focus, be it weakness, pain, or cognitive or communicative dysfunction. Biomarkers may also be useful for identifying patients who will respond best, with a goal to enhance clinical decision making. Combination with drugs or specific types of therapeutic exercise may be necessary to achieve maximal response.

Efficacy, tolerability, and cognitive effects of deep transcranial magnetic stimulation for late-life depression: a prospective randomized controlled trial

Late-life depression (LLD) is a growing worldwide problem due to demographic changes, with limited treatment options due to high rates of pharmacotherapy adverse effects, accessibility of psychotherapy, and tolerability of electroconvulsive therapy. Novel neuromodulation techniques, such as repetitive transcranial magnetic stimulation (rTMS), may overcome these limitations. The objective of this study is to determine the efficacy, tolerability, and cognitive effects of high-dose deep rTMS in LLD. In this study we randomized older adults between 60 and 85 years old with major depressive disorder (MDD) to sham or active deep rTMS (H1 coil, 6012 pulses, 18 Hz, 120% of resting motor threshold) delivered over the dorsolateral and ventrolateral prefrontal cortex 5 days per week over 4 weeks. Our primary outcome was remission of depression in an intention-to-treat analysis. We also assessed change in cognitive functioning with rTMS treatment and tolerability based on adverse effects. Fifty-two participants were randomized to active (n = 25) or sham H1 coil (n = 27). Remission rate was significantly higher with active than sham rTMS (40.0% vs 14.8%) with a number needed to treat of 4.0 (95% CI: 2.1-56.5). There was no change on any measure of executive function and no serious adverse events. Adverse effect profiles were similar between active and sham rTMS, except for reports of pain being significantly more common in the active condition (16.0% vs 0%). High-dose deep rTMS appears to be safe, well tolerated, and efficacious in the treatment of LLD.

Repetitive Deep TMS for Parkinson Disease: A 3-Month Double-Blind, Randomized Sham-Controlled Study

PURPOSE

To study the effects of a repetitive deep transcranial magnetic stimulation (rDTMS) in patients with Parkinson disease using the H5 coil for the low-frequency stimulation of the primary motor cortex, followed by the high-frequency rDTMS of the prefrontal cortex.

METHODS

The main outcome measures were the total and motor scores of the Unified Parkinson's Disease Rating Scale (UPDRS). Secondary measures included rating of depression and quantitative motor tasks.

RESULTS

Forty-eight patients were randomized 1:1 into real or sham rDTMS treatment arms. Analyses (n = 42) of both UPDRS scores revealed a significant main effect for time between baseline and day 90 (end of treatment), indicating that there was an improvement of both scores over time in the whole sample. Although effects of treatment and time-by-treatment were insignificant, simple effects analysis of both measures was significant in the rDTMS group and reached a P-value of 0.06 in the sham group. The response rate was higher in patients with longer disease duration and higher motor UPDRS scores. Side effects were more common in the rDTMS group but were transient and tolerable.

CONCLUSIONS

Although rDTMS treatment exhibited some motor improvements, we could not demonstrate an advantage for real treatment over sham. Further research is required to establish stimulation parameters that may induce potentially more beneficial outcomes, probably in patients with longer and more sever disease.

Transcranial magnetic stimulation for the treatment of cocaine addiction: evidence to date

There is a common consensus in considering substance-use disorders (SUDs) a devastating chronic illness with social and psychological impact. Despite significant progress in understanding the neurobiology of SUDs, therapeutic advances have proceeded at a slower pace, in particular for cocaine-use disorder (CUD). Transcranial magnetic stimulation (TMS) is gaining support as a safe and cost-effective tool in the treatment of SUDs. In this review, we consider human studies that have investigated the efficacy of TMS in achieving therapeutic benefits in treating CUD. All studies conducted to date that have evaluated the therapeutic effect of TMS in CUD are included. We focus on the protocol of stimulation applied, emphasizing the neurophysiological effects of coils employed related to outcomes. Moreover, we examine the subjective and objective measurements used to assess the therapeutic effects along the timeline considered. The revision of scientific literatures underscores the therapeutic potential of TMS in treating CUD. However, the variability in stimulation protocols applied and the lack of methodological control do not allow us to draw firm conclusions, and further studies are warranted to examine the interaction between TMS patterns of stimulation relative to clinical outcomes in depth.

Can deep transcranial magnetic stimulation (DTMS) be used to treat substance use disorders (SUD)? A systematic review

BACKGROUND

Deep transcranial magnetic stimulation (DTMS) is a non-invasive method of stimulating widespread cortical areas and, presumably, deeper neural networks. The current study assessed the effects of DTMS in the treatment of substance use disorders (SUD) using a systematic review.

METHODS

Electronic literature search (PsycInfo, Medline until April 2017) identified k = 9 studies (k = 4 randomized-controlled trials, RCTs, with inactive sham and k = 5 open-label studies). DTMS was most commonly applied using high frequency/intensity (10-20 Hz/100-120% of the resting motor threshold, MT) protocols for 10-20 daily sessions in cases with alcohol, nicotine or cocaine use disorders. The outcome measures were craving and dependence (according to standardized scales) or consumption (frequency, abstinence or results of biological assays) at the end of the daily treatment phases and at the last follow-up.

RESULTS

Acute and longer-term (6-12 months) reductions in alcohol craving were observed after 20 sessions (20 Hz, 120% MT) relative to baseline in k = 4 open-label studies with comorbid SUD and major depressive disorder (MDD). In k = 2 RCTs without MDD, alcohol consumption acutely decreased after 10-12 sessions (10-20 Hz, 100-120% MT) relative to baseline or to sham. Alcohol craving was reduced only after higher frequency/intensity DTMS (20 Hz, 120% MT) relative to sham in k = 1 RCT. Nicotine consumption was reduced and abstinence was increased after 13 sessions (10 Hz, 120% MT) and at the 6-month follow-up relative to sham in k = 1 RCT. Cocaine craving was reduced after 12 sessions (15 Hz, 100% MT) and at the 2-month follow-up relative to baseline in k = 1 open-label study while consumption was reduced after 12 sessions (10 Hz, 100% MT) relative to baseline but not to sham in k = 1 RCT.

CONCLUSIONS

High-frequency DTMS may be effective at treating some SUD both acutely and in the longer-term. Large RCTs with inactive sham are required to determine the efficacy and the optimal stimulation parameters of DTMS for the treatment of SUD.

An Update of a Meta-Analysis on the Clinical Outcomes of Deep Transcranial Magnetic Stimulation (DTMS) in Major Depressive Disorder (MDD)

Abstract. Deep transcranial magnetic stimulation (DTMS) is a noninvasive therapy for treatment-resistant major depressive disorder (MDD). The current study aimed to update a previous meta-analysis by investigating the acute and longer-term clinical outcomes of DTMS and their possible predictors (patient characteristics and stimulation parameters) in unipolar MDD. A systematic literature search identified 11 studies with 282 treatment-resistant, unipolar MDD patients. The clinical outcomes (depression severity, response and remission rates) were evaluated using random-effects meta-analyses. High frequency and intensity DTMS protocol with H1-coil had significant acute antidepressant outcomes and improved some cognitive functions after 20 daily sessions in unipolar MDD. Response rates tended to increase with lower severity of illness. Antidepressant effects were prolonged if maintenance DTMS was used after daily stimulation phases. DTMS consistently improves various symptom domains (antidepressant, cognitive) in treatment-resistant unipolar MDD.

Efficacy of deep rTMS for neuropathic pain in the lower limb: a randomized, double-blind crossover trial of an H-coil and figure-8 coil

OBJECTIVE

Electrical motor cortex stimulation can relieve neuropathic pain (NP), but its use requires patients to undergo an invasive procedure. Repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) using a figure-8 coil can relieve NP noninvasively, but its ability to relieve lower limb pain is still limited. Deep rTMS using an H-coil can effectively stimulate deep brain regions and has been widely used for the treatment of various neurological diseases; however, there have been no clinical studies comparing the effectiveness of figure-8 coils and H-coils. This study assessed the clinical effectiveness of 5 once-daily stimulations with H-coils and figure-8 coils in patients with NP.

METHODS

This randomized, double-blind, 3-way crossover trial examined 18 patients with NP who sequentially received 3 types of stimulations in the M1 for 5 consecutive days; each 5-day stimulation period was followed by a 17-day follow-up period before crossing over to the next type of stimulation. During each rTMS session, patients received a 5-Hz rTMS to the M1 region corresponding to the painful lower limb. The visual analog scale (VAS) and the Japanese version of the short-form McGill Pain Questionnaire 2 (SF-MPQ2-J) were used to measure pain intensity. The primary outcome was VAS score reduction immediately after and 1 hour after intervention.

RESULTS

Both the VAS and SF-MPQ2-J showed significant pain improvement immediately after deep rTMS with an H-coil as compared with the sham group (p < 0.001 and p = 0.049, respectively). However, neither outcome measure showed significant pain improvement when using a figure-8 coil. The VAS also showed significant pain improvement 1 hour after deep rTMS with an H-coil (p = 0.004) but not 1 hour after rTMS using a figure-8 coil. None of the patients exhibited any serious adverse events.

CONCLUSIONS

The current findings suggest that the use of deep rTMS with an H-coil in the lower limb region of the M1 in patients with NP was tolerable and could provide significant short-term pain relief.

Clinical trial registration no.: UMIN000010536 (http://www.umin.ac.jp/ctr/)

The epigenetic component of the brain response to electromagnetic stimulation in Parkinson's Disease patients: A literature overview

Modulations of epigenetic machinery, namely DNA methylation pattern, histone modification, and non-coding RNAs expression, have been recently included among the key determinants contributing to Parkinson's Disease (PD) aetiopathogenesis and response to therapy. Along this line of reasoning, a set of experimental findings are highlighting the epigenetic-based response to electromagnetic (EM) therapies used to alleviate PD symptomatology, mainly Deep Brain Stimulation (DBS) and Transcranial Magnetic Stimulation (TMS). Notwithstanding the proven efficacy of EM therapies, the precise molecular mechanisms underlying the brain response to these types of stimulations are still far from being elucidated. In this review we provide an overview of the epigenetic changes triggered by DBS and TMS in both PD patients and neurons from different experimental animal models. Furthermore, we also propose a critical overview of the exposure modalities currently applied, in order to evaluate the technical robustness and dosimetric control of the stimulation, which are key issues to be carefully assessed when new molecular findings emerge from experimental studies. Bioelectromagnetics. 39:3-14, 2018. © 2017 Wiley Periodicals, Inc.

Comparison of a special designed high intensity coil to a standard round coil-TMS-setting

BACKGROUND

Routine diagnostic Transcranial Magnetic Stimulation (TMS) is performed with a round coil (RC) for cranial and spinal root stimulation, being less successful for motor evoked potentials (MEP) of lower limb muscles. MEP elicited with a special configured flat figure-of-eight coil designed for high intensity stimulation (HI-coil) were compared to RC with regard to handling, efficiency, and physiological properties of MEP.

NEW METHODS

MEP elicited with HI-coil and 9-cm diameter RC for cortical, spinal and peripheral stimulation (PES) were compared for Motor threshold (MT), latencies and amplitudes of bilateral Abductor pollicis brevis (APB) and Abductor hallucis muscles (AH).

RESULTS AND COMPARISON WITH EXISTING METHODS

MT for HI-coil were significantly lower for cortical and spinal root stimulation compared to RC (APB: 37% vs. 48%; AH: 58% vs. 72%). MEP-latencies elicited with HI-coil and RC were without significant difference. AH-MEP amplitudes were significantly larger for HI-coil cortical (705±980μV vs. 370±280μV) and root stimulation (260±210μV vs. 151±100μV). Amplitudes elicited by PES compared to HI-coil were always significantly larger.

CONCLUSION

Results for cortical and spinal root stimulation with regards to latencies and amplitudes for APB were equivalent between HI-coil and RC. PES was superior in achieving supramaximal stimulation in terms of amplitudes. The use of the HI-coil might be advantageous for MEP of lower extremity muscles with emphasis on pathologic conditions requiring higher stimulation intensities.

How to Use the H1 Deep Transcranial Magnetic Stimulation Coil for Conditions Other than Depression

Deep transcranial magnetic stimulation (dTMS) is a relatively new technique that uses different coils for the treatment of different neuropathologies. The coils are made of soft copper windings in multiple planes that lie adjacent to the skull. They are located within a special helmet so that their magnetic fields combine and improve depth penetration. The H1 dTMS coil is designed to stimulate bilateral prefrontal cortices with greater effective stimulation over the left than the right. By positioning the left side of the coil close to the left dorsolateral prefrontal cortex (DLPFC), the H1 coil was used in a multisite study, leading to FDA approval for treatment-resistant depression. In this same position, the H1 coil was also explored as a possible treatment for negative symptoms of schizophrenia, bipolar depression, and migraine. When moved to different positions over the subject's skull, the H1 coil was also explored as a possible treatment for other conditions. Such manipulation of the H1 coil was demonstrated for PTSD and alcohol dependence by positioning it over the medial prefrontal cortex (mPFC), for anxiety by positioning it over the right prefrontal cortex (rPFC), for auditory hallucinations and tinnitus by positioning it over the temporoparietal junction (TPJ), and for Parkinson's and fatigue from multiple sclerosis (MS) by positioning it over the motor cortex (MC) and PFC. Corresponding electrical field diagrams measured with an oscilloscope through a saline-filled head are included.

Navigated transcranial magnetic stimulation for glioma removal: prognostic value in motor function recovery from postsurgical neurological deficits

OBJECTIVE The aim of the present study was to evaluate the usefulness of navigated transcranial magnetic stimulation (nTMS) as a prognostic predictor for upper-extremity motor functional recovery from postsurgical neurological deficits. METHODS Preoperative and postoperative nTMS studies were prospectively applied in 14 patients (mean age 39 ± 12 years) who had intraparenchymal brain neoplasms located within or adjacent to the motor eloquent area in the cerebral hemisphere. Mapping by nTMS was done 3 times, i.e., before surgery, and 1 week and 3 weeks after surgery. To assess the response induced by nTMS, motor evoked potential (nTMS-MEP) was recorded using a surface electromyography electrode attached to the abductor pollicis brevis (APB). The cortical locations that elicited the largest electromyography response by nTMS were defined as hotspots. Hotspots for APB were confirmed as positive responsive sites by direct electrical stimulation (DES) during awake craniotomy. The distances between hotspots and lesions (D_HS-L) were measured. Postoperative neurological deficits were assessed by manual muscle test and dynamometer. To validate the prognostic value of nTMS in recovery from upper-extremity paresis, the following were investigated: 1) the correlation between D_HS-L and the serial grip strength change, and 2) the correlation between positive nTMS-MEP at 1 week after surgery and the serial grip strength change. RESULTS From the presurgical nTMS study, MEPs from targeted muscles were identified in 13 cases from affected hemispheres. In one case, MEP was not evoked due to a huge tumor. Among 9 cases from which intraoperative DES mapping for hand motor area was available, hotspots for APB identified by nTMS were concordant with DES-positive sites. Compared with the adjacent group (D_HS-L < 10 mm, n = 6), the nonadjacent group (D_HS-L ≥ 10 mm, n = 7) showed significantly better recovery of grip strength at 3 months after surgery (p < 0.01). There were correlations between D_HS-L and recovery of grip strength at 1 week, 3 weeks, and 3 months after surgery (r = 0.74, 0.68, and 0.65, respectively). Postsurgical nTMS was accomplished in 13 patients. In 9 of 13 cases, nTMS-MEP from APB muscle was positive at 1 week after surgery. Excluding the case in which nTMS-MEP was negative from the presurgical nTMS study, recoveries in grip strength were compared between 2 groups, in which nTMS-MEP at 1 week after surgery was positive (n = 9) or negative (n = 3). Significant differences were observed between the 2 groups at 1 week, 3 weeks, and 3 months after surgery (p < 0.01). Positive nTMS-MEP at 1 week after surgery correlated well with the motor recovery at 1 week, 3 weeks, and 3 months after surgery (r = 0.87, 0.88, and 0.77, respectively). CONCLUSIONS Navigated TMS is a useful tool for identifying motor eloquent areas. The results of the present study have demonstrated the predictive value of nTMS in upper-extremity motor function recovery from postsurgical neurological deficits. The longer D_HS-L and positive nTMS-MEP at 1 week after surgery have prognostic values of better recovery from postsurgical neurological deficits.

Treating Clinical Depression with Repetitive Deep Transcranial Magnetic Stimulation Using the Brainsway H1-coil

Repetitive transcranial magnetic stimulation (rTMS) is an emerging non-pharmacological approach to treating many brain-based disorders. rTMS uses electromagnetic coils to stimulate areas of the brain non-invasively. Deep transcranial magnetic stimulation (dTMS) with the Brainsway H1-coil system specifically is a type of rTMS indicated for treating patients with major depressive disorder (MDD) who are resistant to medication. The unique H1-coil design of this device is able to stimulate neuronal pathways that lie deeper in the targeted brain areas than those reached by conventional rTMS coils. dTMS is considered to be low-risk and well tolerated, making it a viable treatment option for people who have not responded to medication or psychotherapy trials for their depression.

Randomized, sham-control studies have demonstrated that dTMS produces significantly greater improvement in depressive symptoms than sham dTMS treatment in patients with major depression that has not responded to antidepressant medication. In this paper, we will review the methodology for treating major depression with dTMS using an H1-coil.

Deep transcranial magnetic stimulation (dTMS) - beyond depression

INTRODUCTION

Deep transcranial magnetic stimulation (dTMS) utilizes different H-coils to study and treat a variety of psychiatric and neurological conditions with identifiable brain targets. The availability of this technology is dramatically changing the practice of psychiatry and neurology as it provides a safe and effective way to treat even drug-resistant patients. However, up until now, no effort was made to summarize the different types of H-coils that are available, and the conditions for which they were tested. Areas covered: Here we assembled all peer reviewed publication that used one of the H-coils, together with illustrations of the effective field they generate within the brain. Currently, the technology has FDA clearance for depression and European clearance for additional disorders, and multi-center trials are exploring its safety and effectiveness for OCD, PTSD, bipolar depression and nicotine addiction. Expert commentary: Taken together with positive results in smaller scale experiments, dTMS coils represent a non-invasive way to manipulate pathological activity in different brain structures and circuits. Advances in stimulation and imaging methods can now lead to efficacious and logical treatments. This should reduce the stigma associated with mental disorders, and improve access to psychiatric treatment.

Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations From a TMS Coil

GOALS

Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of this study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup.

METHODS

We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100 000 observation points, and two distinct pulse rise times; thus, providing a representative number of different datasets for comparison, while also using other numerical data.

RESULTS

Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average.

CONCLUSION

The simple analytical model tested in this study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body.

SIGNIFICANCE

At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women.

Bilateral Transcranial Magnetic Stimulation of the Prefrontal Cortex Reduces Cocaine Intake: A Pilot Study

BACKGROUND

Chronic cocaine consumption is associated with a decrease in mesolimbic dopamine transmission that maintains drug intake. transcranial magnetic stimulation (TMS) is gaining reliability, a useful therapeutic tool in drug addiction, since it can modulate cortico-limbic activity resulting in reduction of drug craving.

AIMS

In the present study, we investigated the therapeutic effect of bilateral TMS of prefrontal cortex (PFC) in reducing cocaine intake, in a sample of treatment-seeking patients with current cocaine use disorder (DSM-V).

METHODS

Ten cocaine addicts (DSM-V) were randomly assigned to the active or sham stimulation protocol in a double-blind experimental design. Twelve repetitive TMS (rTMS) sessions were administered three times a week for 4 weeks at 100% of motor threshold, over bilateral PFC. Cocaine intake (ng/mg) was assessed by hair analysis at baseline (before treatment, T0), after 1 month (end of treatment, T1), 3 (T2), and 6 (T3) months later. All subjects received psychological support weekly.

RESULTS

The two-way ANOVA for repeated measures did not show a significant effect of the interaction between time and treatment (F 4,32 = 0.35; p = 0.87). Despite that result indicated no difference in the effect of the two conditions (active vs. sham) along time, a decreasing trend in cocaine consumption in active TMS group (F 3,23 = 3.42; p = 0.04) vs. sham (F 3,15 = 1.88; p = 0.20) was observed when we performed exploratory analysis with time as factor. Indeed, Post hoc comparisons showed a significant reduction in the amount of cocaine detected from the onset to 3 months later (T0-T2; p = 0.02) and to the end of treatment (T0-T3; p = 0.01) in addicts from the active group.

CONCLUSION

Bilateral rTMS of PFC at 10 Hz did not show a significant effect on cocaine intake compared to sham. However, a long-term reduction on cocaine intake in active TMS-treated patients was observed when we considered the time as factor. Further studies are required to confirm these encouraging but preliminary findings, in order to consolidate rTMS as a valid tool to treat cocaine addiction.

Benefits of Deep Transcranial Magnetic Stimulation in Alzheimer Disease: Case Series

BACKGROUND

Patients diagnosed with Alzheimer disease (AD) show severe cognitive deficits. Decline in memory, language, and executive function have repeatedly been reported. Although AD affects 60% to 80% of demented elderly patients, there is currently no cure and limited treatment alternatives.

OBJECTIVES

The aim of the study was to evaluate the feasibility of stimulating prefrontal cortex (PFC) with deep transcranial magnetic stimulation (dTMS) to ameliorate cognitive deficits in patients suffering from AD.

METHODS

Eleven patients (6 males; mean [SD] age, 76 [7] years) in moderate to severe stages of AD received dTMS over the PFC for 20 sessions. Computerized battery (Mindstreams [MS]) and neuropsychological testing (Addenbrooke Cognitive Examination [ACE]) were used to assess cognitive performance before and after treatment.

RESULTS

Compared with baseline, 60% of patients performed better on the MS battery and 77% of patients performed better on the ACE testing at the end of dTMS treatment. None of the patients performed worse on both tests at the end of treatment. The DTMS effects on the group mean in ACE and MS approached significance (P = 0.065 and P = 0.086, respectively). A dTMS-induced improvement in the ACE was significant (P = 0.001) on patients in more progressed stage (n = 6). Change in ACE negatively correlated with score at baseline.

CONCLUSIONS

In sum, the current report of this novel technique indicates that deep stimulation might lead to preservation and even improvement of cognitive functions, at least during the time of treatment. Further examinations should report of long-term effects of this technique.

Cognitive functioning and deep transcranial magnetic stimulation (DTMS) in major psychiatric disorders: A systematic review

Deep transcranial magnetic stimulation (DTMS) is a non-invasive brain stimulation method mostly utilised in the treatment of major depression. The aim of the current study was to systematically review the literature on the cognitive effects of DTMS applied with the H-coil system in major psychiatric disorders. Following a literature search in PsycInfo and PubMed (any time to December 2015), 13 out of 32 studies on DTMS and cognitive functioning were included in the current review. Three studies included 38 healthy participants, eight studies included 158 unipolar or bipolar depression patients and two studies included 45 schizophrenia patients. Low-frequency DTMS (1-3 sessions) had little effect on cognitive functioning in healthy participants. The most consistent cognitive and clinical improvements were reported in the short-term (after 20 daily sessions of high-frequency DTMS with H1-coil) in studies with major depression patients. There was also a trend towards a short-term cognitive and clinical improvement in studies with schizophrenia patients. High-frequency DTMS might improve cognitive functioning and alleviate clinical symptoms in the short-term, particularly in major depression. However, this conclusion is based on data from mostly uncontrolled, open-label studies with patients receiving concurrent antidepressants or antipsychotics. Randomised, sham-controlled trials are needed to investigate the magnitude of the cognitive outcomes of DTMS in the short-term and beyond the daily stimulation phase in major psychiatric disorders.

Technical aspects of neurostimulation: Focus on equipment, electric field modeling, and stimulation protocols

Neuromodulation is a field of science, medicine, and bioengineering that encompasses implantable and non-implantable technologies for the purpose of improving quality of life and functioning of humans. Brain neuromodulation involves different neurostimulation techniques: transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), vagus nerve stimulation (VNS), and deep brain stimulation (DBS), which are being used both to study their effects on cognitive brain functions and to treat neuropsychiatric disorders. The mechanisms of action of neurostimulation remain incompletely understood. Insight into the technical basis of neurostimulation might be a first step towards a more profound understanding of these mechanisms, which might lead to improved clinical outcome and therapeutic potential. This review provides an overview of the technical basis of neurostimulation focusing on the equipment, the present understanding of induced electric fields, and the stimulation protocols. The review is written from a technical perspective aimed at supporting the use of neurostimulation in clinical practice.

Acute reduction in anxiety after deep transcranial magnetic stimulation (DTMS) in unipolar major depression- a systematic review and meta-analysis

The current study investigated the anxiolytic properties of the deep transcranial magnetic stimulation (DTMS) in unipolar major depression using a systematic literature review and meta-analysis. Compared to baseline, large anxiolytic and antidepressant outcomes were obtained after 20 daily sessions of high-frequency DTMS according to data from six open-label studies with 95 patients. Unlike the antidepressant effect, the anxiolytic effect was more heterogeneous among studies and did not depend on concurrent treatment with antidepressants.

The Neurophysiologist Perspective into MS Plasticity

Multiple sclerosis (MS) is a frequent, highly debilitating inflammatory demyelinating disease, starting to manifest in early adulthood and presenting a wide variety of symptoms, which are often resistant to pharmacological treatments. Cortical dysfunctions have been demonstrated to be key components of MS condition, and plasticity of the corticospinal motor system is highly involved in major MS symptoms, such as fatigue, spasticity, or pain. Cortical dysfunction in MS can be studied with neurophysiological tools, such as electroencephalography (EEG) and related techniques (evoked potentials) or transcranial magnetic stimulation (TMS). These techniques are now widely used to provide essential elements of MS diagnosis and can also be used to modulate plasticity. Indeed, the recent development of non-invasive brain stimulation techniques able to induce cortical plasticity, such as repetitive TMS or transcranial direct current stimulation, has brought promising results as add-on treatments. In this review, we will focus on the use of these tools (EEG and TMS) to study plasticity in MS and on the major techniques used to modulate plasticity in MS.

Systems Neuroengineering: Understanding and Interacting with the Brain

In this paper, we review the current state-of-the-art techniques used for understanding the inner workings of the brain at a systems level. The neural activity that governs our everyday lives involves an intricate coordination of many processes that can be attributed to a variety of brain regions. On the surface, many of these functions can appear to be controlled by specific anatomical structures; however, in reality, numerous dynamic networks within the brain contribute to its function through an interconnected web of neuronal and synaptic pathways. The brain, in its healthy or pathological state, can therefore be best understood by taking a systems-level approach. While numerous neuroengineering technologies exist, we focus here on three major thrusts in the field of systems neuroengineering: neuroimaging, neural interfacing, and neuromodulation. Neuroimaging enables us to delineate the structural and functional organization of the brain, which is key in understanding how the neural system functions in both normal and disease states. Based on such knowledge, devices can be used either to communicate with the neural system, as in neural interface systems, or to modulate brain activity, as in neuromodulation systems. The consideration of these three fields is key to the development and application of neuro-devices. Feedback-based neuro-devices require the ability to sense neural activity (via a neuroimaging modality) through a neural interface (invasive or noninvasive) and ultimately to select a set of stimulation parameters in order to alter neural function via a neuromodulation modality. Systems neuroengineering refers to the use of engineering tools and technologies to image, decode, and modulate the brain in order to comprehend its functions and to repair its dysfunction. Interactions between these fields will help to shape the future of systems neuroengineering-to develop neurotechniques for enhancing the understanding of whole-brain function and dysfunction, and the management of neurological and mental disorders.