Repetitive transcranial magnetic stimulation in the treatment of epilepsia partialis continua

Long-term Effect of Multichannel tDCS Protocol in Patients with Central Cortex Epilepsies Associated with Epilepsia Partialis Continua

Epilepsia partialis continua (EPC) is a rare type of focal motor status epilepticus that causes continuous muscle jerking in a specific part of the body. Experiencing this type of seizure, along with other seizure types, such as focal motor seizures and focal to bilateral tonic-clonic seizures, can result in a disabling situation. Non-invasive brain stimulation methods like transcranial direct current stimulation (tDCS) show promise in reducing seizure frequency (SF) when medications are ineffective. However, research on tDCS for EPC and related seizures is limited. We evaluated personalized multichannel tDCS in drug-resistant EPC of diverse etiologies for long-term clinical efficacy We report three EPC patients undergoing a long-term protocol of multichannel tDCS. The patients received several cycles (11, 9, and 3) of five consecutive days of stimulation at 2 mA for 2 × 20 min, targeting the epileptogenic zone (EZ), including the central motor cortex with cathodal electrodes. The primary measurement was SF changes. In three cases, EPC was due to Rasmussen's Encephalitis (case 1), focal cortical dysplasia (case 2), or remained unknown (case 3). tDCS cycles were administered over 6 to 22 months. The outcomes comprised a reduction of at least 75% in seizure frequency for two patients, and in one case, a complete cessation of severe motor seizures. However, tDCS had no substantial impact on the continuous myoclonus characterizing EPC. No serious side effects were reported. Long-term application of tDCS cycles is well tolerated and can lead to a considerable reduction in disabling seizures in patients with various forms of epilepsy with EPC.

Stereo electroencephalography-guided radiofrequency ablation in focal epilepsia partialis continua: illustrative case

BACKGROUND

Epilepsia partialis continua (EPC) is a variant of focal motor status epilepticus that can occur as a single or repetitive episode with progressive or nonprogressive characteristics.

OBSERVATIONS

The authors describe the feasibility of identifying focal EPC in a 33-year-old woman using video electroencephalography (VEEG), electroencephalography source localization, [18F]fluorodeoxyglucose positron emission tomography, magnetic resonance imaging, and psychiatric and neuropsychological assessments and of treating it with stereo electroencephalography-guided radiofrequency (SEEG-RF) ablation. EPC comprised recurrent myoclonus of the right thigh and iliopsoas with a progressive pain syndrome after left anterior-temporo-mesial resection. Switching between VEEG under regular and epidural block helped to define myoclonus as the presenting ictal symptom with a suspected seizure onset zone in the left parietal paramedian lobule. After the epileptic network was identified, SEEG-RF ablation abolished all seizures. No correlation was found between pain and VEEG/SEEG abnormalities. Rehabilitation began 3 days after the SEEG-RF ablation. By 1 year of follow-up, the patient had no EPC and could walk with assistance in rehabilitation; however, due to the abrupt abolishment of EPC and underlying psychological factors, the patient perceived her pain as overriding, which prevented her from walking.

LESSONS

The application of SEEG-RF ablation is an efficient therapeutic option for focal EPC with special concerns regarding concurrent nonepileptic pain. https://thejns.org/doi/10.3171/CASE23611.

Modulatory effects of real-time electromagnetic stimulation on epileptiform activity in juvenile rat hippocampus based on multi-electrode array recordings

Electromagnetic stimulation (EMS) has proven to be useful for the focal suppression of epileptiform activity (EFA) in the hippocampus. There is a critical period during EFA for achieving the transition from brief interictal discharges (IIDs) to prolonged ictal discharges (IDs), and it is unknown whether EMS can modulate this transition. Therefore, this study aimed to evaluate the intensity- and time-dependent effect of EMS on the transition of EFA. A juvenile rat EFA model was constructed by perfusing magnesium-free artificial cerebrospinal fluid (aCSF) on brain slices, and the induced EFA was recorded using a micro-electrode array (MEA) platform. After a stable EFA event was recorded for some time, real-time pulsed magnetic stimulation with low and high peak-to-peak input magnetic field intensities was carried out. A 5-min intervention with real-time magnetic fields with low intensity was found to reduce the amplitude of IDs (ID events still existed), whereas a 5-min intervention with real-time magnetic fields with high input voltages completely suppressed IDs. Short-time magnetic fields (9s and 1min) with high or low input intensity had no effect on EFA. Real-time magnetic fields can block the normal EFA process from IIDs to IDs (i.e., a complete EFA cycle) and this suppression effect is dependent on input intensities and intervention duration. The experimental findings further indicate that magnetic stimulation may be chosen as an alternative antiepileptic therapy.

Neuromodulation in Children with Drug-Resistant Epilepsy

The introduction of neuromodulation was a revolutionary advancement in the antiseizure armamentarium for refractory epilepsy. The basic principle of neuromodulation is to deliver an electrical stimulation to the desired neuronal site to modify the neuronal functions not only at the site of delivery but also at distant sites by complex neuronal processes like disrupting the neuronal circuitry and amplifying the functions of marginally functional neurons. The modality is considered open-loop when electrical stimulation is provided at a set time interval or closed-loop when delivered in response to an incipient seizure. Neuromodulation in individuals older than 18 years with epilepsy has proven efficacious and safe. The use of neuromodulation is extended off-label to pediatric patients with epilepsy and the results are promising. Vagus nerve stimulation (VNS), responsive neurostimulation (RNS), and deep brain stimulation (DBS) are Food and Drug Administration-approved therapeutic techniques. The VNS provides retrograde signaling to the central nervous system, whereas DBS and RNS are more target specific in the central nervous system. While DBS is open-loop and approved for stimulation of the anterior nucleus of the thalamus, the RNS is closed-loop and can stimulate any cortical or subcortical structure. We will review different modalities and their clinical efficacy in individuals with epilepsy, with a focus on pediatric patients.

Neurostimulation as a Method of Treatment and a Preventive Measure in Canine Drug-Resistant Epilepsy: Current State and Future Prospects

Modulation of neuronal activity for seizure control using various methods of neurostimulation is a rapidly developing field in epileptology, especially in treatment of refractory epilepsy. Promising results in human clinical practice, such as diminished seizure burden, reduced incidence of sudden unexplained death in epilepsy, and improved quality of life has brought neurostimulation into the focus of veterinary medicine as a therapeutic option. This article provides a comprehensive review of available neurostimulation methods for seizure management in drug-resistant epilepsy in canine patients. Recent progress in non-invasive modalities, such as repetitive transcranial magnetic stimulation and transcutaneous vagus nerve stimulation is highlighted. We further discuss potential future advances and their plausible application as means for preventing epileptogenesis in dogs.

Bridging the gap: TMS-EEG from Lab to Clinic

The combination of transcranial magnetic stimulation (TMS) and electroencephalography (EEG) has reached technological maturity and has been an object of significant scientific interest for over two decades. Ιn parallel, accumulating evidence highlights the potential of TMS-EEG as a useful tool in the field of clinical neurosciences. Nevertheless, its clinical utility has not yet been established, partly because technical and methodological limitations have created a gap between an evolving scientific tool and standard clinical practice. Here we review some of the identified gaps that still prevent TMS-EEG moving from science laboratories to clinical practice. The principal and partly overlapping gaps include: 1) complex and laborious application, 2) difficulty in obtaining high-quality signals, 3) suboptimal accuracy and reliability, and 4) insufficient understanding of the neurobiological substrate of the responses. All these four aspects need to be satisfactorily addressed for the method to become clinically applicable and enter the diagnostic and therapeutic arena. In the current review, we identify steps that might be taken to address these issues and discuss promising recent studies providing tools to aid bridging the gaps.

Repetitive transcranial magnetic stimulation (rTMS) as therapy in an infant with epilepsia partialis continua

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rTMS was safely performed in a 10-month old at 10 Hz without apparent adverse effects.

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rTMS was successfully performed in an infant for refractory epilepsia partialis continua.

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rTMS may have a treatment role in recurring, refractory epilepsia partialis continua in children.

Introduction: We present a case of a 10-month-old girl undergoing repetitive TMS (rTMS) for the treatment of drug-resistant epilepsy. Case report: A 10-month-old girl, later diagnosed with pathogenic POLG1 mutations, presented to our institution with chronic progressive EPC (epilepsia partialis continua) manifesting as a frequent, left-sided, synchronous continuous jerking of the arms and legs. The seizures were drug-resistant to multiple antiseizure medications and epilepsy surgery, responding only to continuous anesthesia. rTMS therapy was attempted to interrupt seizures. Results: rTMS therapy, using an activating protocol to introduce a temporary lesion effect, was used to interrupt persistent, ongoing seizures. Conclusion: rTMS can be safely used to abort seizures in patients as young as 10 months old.

Neuromodulation in Pediatric Epilepsy

Neuromodulation alters neuronal activity with electrical impulses delivered to the targeted neurologic sites. The various neuromodulation options available today for epilepsy management have proven efficacy primarily in adult trials. These include open-loop stimulation with invasive vagus nerve stimulation and deep brain stimulation, as well as closed-loop responsive neurostimulation. The use of neurostimulation therapy to treat intractable epilepsy in children is growing. This article reviews the literature, historical background, and current principles in pediatric patients.

Responsive neurostimulation for focal motor status epilepticus

No clear evidence‐based treatment paradigm currently exists for refractory and super‐refractory status epilepticus, which can result in significant mortality and morbidity. While patients are typically treated with antiepileptic drugs and anesthetics, neurosurgical neuromodulation techniques can also be considered. We present a novel case in which responsive neurostimulation was used to effectively treat a patient who had developed super‐refractory status epilepticus, later consistent with epilepsia partialis continua, that was refractory to antiepileptic drugs, immunomodulatory therapies, and transcranial magnetic stimulation. This case demonstrates how regional therapy provided by responsive neurostimulation can be effective in treating super‐refractory status epilepticus through neuromodulation of seizure networks.

Slow repetitive transcranial magnetic stimulation in refractory juvenile myoclonic epilepsies

OBJECTIVE

The objective of the study was to investigate the effects of slow repetitive transcranial magnetic stimulation (rTMS) on patients with refractory juvenile myoclonic epilepsy (JME).

METHODS

One thousand pulses with the intensity of 120% active motor threshold (AMT) at 0.2 Hz frequency were applied on 5 consecutive days in 10 patients with refractory JME. Sham rTMS was performed after 3 months. Electroencephalography (EEG) examinations were performed before rTMS, on the 5th day, and 1, 2, 4, and 8 weeks after rTMS. Resting motor threshold (RMT), AMT, and cortical silent periods (CSPs) were recorded before the application and at the end of day 5. The changes in the quality of life were evaluated using the Quality of Life in Epilepsy Inventory (QOLIE-31).

RESULTS

No adverse effects were observed. The number of seizures decreased by 29-50%, and interictal discharge durations decreased 2 weeks after the real rTMS. No significant difference was observed between the AMT and RMT values recorded before and after the stimulations. Statistically significant increases in CSP duration and quality of life scores were found following real rTMS. Repetitive transcranial magnetic stimulation may be considered as a safe treatment option in refractory JME.

CONCLUSION

This study provides some positive evidence that rTMS may be effective in resistant JME.

Physiology-Based Treatment of Myoclonus

Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and pathophysiological mechanisms. Treatment of myoclonus is vital to improving the quality of life of patients with these disorders. The optimal treatment strategy for myoclonus is best determined based upon careful evaluation and consideration of the underlying etiology and neurophysiological classification. Electrophysiological testing including EEG (electroencephalogram) and EMG (electromyogram) data is helpful in determining the neurophysiological classification of myoclonus. The neurophysiological subtypes of myoclonus include cortical, cortical-subcortical, subcortical-nonsegmental, segmental, and peripheral. Levetiracetam, valproic acid, and clonazepam are often used to treat cortical myoclonus. In cortical-subcortical myoclonus, treatment of myoclonic seizures is prioritized, valproic acid being the mainstay of therapy. Subcortical-nonsegmental myoclonus may be treated with clonazepam, though numerous agents have been used depending on the etiology. Segmental and peripheral myoclonus are often resistant to treatment, but anticonvulsants and botulinum toxin injections may be of utility depending upon the case. Pharmacological treatments are often hampered by scarce evidence-based knowledge, adverse effects, and variable efficacy of medications.

Review of Transcranial Magnetic Stimulation in Epilepsy

PURPOSE

Despite the availability of numerous pharmacologic and nonpharmacologic antiseizure therapies, a fraction of patients with epilepsy remain refractory to current treatment options, underscoring the need for novel drugs and neuromodulatory therapies. Transcranial magnetic stimulation (TMS), coupled with either electromyography or electroencephalography, enables rapid measurement of the cortical excitation/inhibition ratio, which is pathologically shifted toward excess excitability in patients with epilepsy. In this review, we summarize: (1) TMS protocols that have been deployed to identify promising compounds in the antiepilepsy drug (AED)-development pipeline, and (2) the therapeutic potential of TMS in the treatment of drug-resistant seizures.

METHODS

A focused literature review of the use of TMS in epilepsy, using a PubMed search, was performed. Over 70 articles were included that pertained to: (1) the use of TMS-EMG and TMS-EEG in elucidating the mechanisms of action of AEDs and in discovering potential new AEDs; and (2) the use of repetitive TMS in the treatment of seizures.

FINDINGS

Studies from the literature have reported that AEDs alter TMS-derived metrics, typically by leading to a net increase in cortical inhibition with successful therapy. Preclinical TMS work in rodent models of epilepsy has led to the development of novel antiseizure drug compounds. Clinical translational studies of TMS have been used to determine guidelines on the dosages of other agents in the AED pipeline in preparation for clinical trials. Several studies have described the use of therapeutic repetitive TMS in both the ictal and interictal states of epilepsy, with inconsistent results.

IMPLICATIONS

TMS has diagnostic and therapeutic potential in epilepsy. TMS-derived markers can enable early-stage measures of AED target engagement, and can facilitate studies of the pharmacokinetic and pharmacodynamic properties of AEDs. TMS may also be used in the early prediction of the efficacy of different AEDs in treating patients, and in direct neuromodulation of epileptic networks. From the therapeutics perspective, despite favorable results in some trials, the optimization of treatment paradigms and the determination of ideal candidates for TMS are still needed. Finally, preclinical experiments of TMS have provided mechanistic insight into its effects on the excitation/inhibition ratio, and may facilitate rational drug-device coupling paradigms. Overall, the capacity of TMS in both the modulation and measurement of changes in cortical excitability highlights its unique role in advancing antiepilepsy therapeutics.

Cortical excitability in epilepsy and the impact of antiepileptic drugs: transcranial magnetic stimulation applications

INTRODUCTION

Epileptic conditions are characterized by impaired cortical excitation/inhibition balance and interneuronal disinhibition. Transcranial magnetic stimulation (TMS) is a neurophysiological method that assesses brain excitation/inhibition.

AREA COVERED

This review was written after a detailed search in PubMed, EMBASE, ISI web of science, SciELO, Scopus, and Cochrane Controlled Trials databases from 1990 to 2020. It summarizes TMS applications for diagnostic and therapeutic purposes in epilepsy. TMS studies help to distinguish different epilepsy conditions and explore the antiepileptic drugs' (AEDs') effects on neuronal microcircuits and plasticity mechanisms. Repetitive TMS studies showed that low-frequency rTMS (0.33-1 Hz) can reduce seizures' frequency in refractory epilepsy or pause ongoing seizures; however, there is no current approval for its use in such patients as adjunctive treatment to AEDs.

EXPERT OPINION

There are variable and conflicting TMS results which reflect the distinct pathogenic mechanisms of each epilepsy condition, the dynamic epileptogenic process over the long disease course resulting in the development of recurrent spontaneous seizures and/or progression of epilepsy after it is established, and the differential effect of AEDs on cortical excitability. Future epilepsy research should focus on combined TMS/functional connectivity studies that explore the complex cortical excitability circuits and networks using different TMS parameters and techniques.

Safety and Tolerability of Repetitive Transcranial Magnetic Stimulation During Pregnancy: A Case Report and Literature Review

Patients with neuropsychiatric disease may benefit from repetitive transcranial magnetic stimulation as a nonpharmacologic alternative to relieve symptoms of major depression, obsessive compulsive disorder, and perhaps other syndromes such as epilepsy. We present a case of repetitive transcranial magnetic stimulation treatment as an adjunct therapy for a patient experiencing refractory epileptic seizures during the third trimester of pregnancy. Notably, the patient tolerated repetitive transcranial magnetic stimulation well, without adverse events, and delivered a healthy child. We also summarize the current literature pertaining to therapeutic repetitive transcranial magnetic stimulation use during pregnancy.

Transcranial Magnetic Stimulation as Treatment in Multiple Neurologic Conditions

PURPOSE OF REVIEW

Transcranial magnetic stimulation (TMS) is a method of Non-Invasive Brain Stimulation that is based on electro-physical principles discovered by Michael Faraday. A TMS device is made of one or two copper coils, positioned superficially to a site of interest in the brain, to non-invasively produce a brief magnetic pulse to an estimated depth from the surface of the scalp with the following axonal depolarization. This axonal depolarization activates cortical and subcortical networks with multiple effects. There are different methods of TMS used, all with different mechanisms of action. TMS is well tolerated with very few side effects.

RECENT FINDINGS

TMS is now approved for major depression disorder and obsessive-compulsive disorder. There is significant data to consider approval of TMS for many neurological disorders. This is a review of the uses of TMS in diverse neurological conditions, including stroke and spasticity, migraine, and dementia. TMS is a device that utilizes non-invasive brain stimulation, and it has shown promising results with objective clinical and basic science data. Its ability to trigger neuronal plasticity and potentiating synaptic transmission gives it incredible therapeutic potential. There are diverse mechanisms of action, and this could be troublesome in elaborating clinical trials and standardization of therapy.

No effect of electrical transcranial direct current stimulation adjunct treatment for epilepsia partialis continua in POLG disease

We report a 15-year-old female with POLG-related mitochondrial disease who developed severe multifocal epilepsia partialis continua, unresponsive to standard anti seizure drug treatment and general anesthesia. Based on an earlier case report, we treated her focal seizures that affected her right upper limb with 20-min sessions of transcranial direct current stimulation (tDCS) at an intensity of 2 mA on each of five consecutive days. The cathode was placed over the left primary motor cortex, the anode over the contralateral orbitofrontal cortex. Surface electromyography (EMG) were recorded 20 min before, 20 min during, and 20 min after four of five tDCS sessions to measure its effect on the muscle jerks. The electroencephalography (EEG) was recorded before and after tDCS to measure the frequency of spikes. Our results showed no statistically or clinically significant reduction of seizures or epileptiform activity using EEG and EMG, with this treatment protocol. To our knowledge, this is only the second time that adjunct tDCS treatment of epileptic seizures has been tried in POLG-related mitochondrial disease. Taken together with the positive findings from the earlier case report, the present study highlights that more data are needed to determine if, and under which parameters, the treatment is effective.

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Case report of multifocal epilepsy in POLG disease with upper limp myoclonus.

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Epileptic activity resulting in myoclonus was treated with 5 days of 20 minutes cathodal 2 mA tDCS over left motor cortex.

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tDCS treatment did not yield significant reduction of myoclonus activity.

Transcranial Magnetic Stimulation for the Treatment of Pediatric Neurological Disorders

PURPOSE OF REVIEW

Repetitive transcranial magnetic stimulation (rTMS) is a form of noninvasive brain stimulation that is used for the treatment of migraine and major depression in adults and is now being evaluated for use in other disorders. The purpose of this review is to summarize the physiology underlying TMS, the safety and tolerability in pediatric patients, and the evidence for TMS efficacy in the treatment of pediatric neurologic disorders.

RECENT FINDINGS

Studies investigating rTMS for adolescent depression, hemiparesis due to pediatric stroke, autism, and tics/Tourette syndrome have demonstrated some therapeutic benefit. rTMS has been insufficiently studied for migraine in children despite benefits demonstrated for adult migraine. Evidence for rTMS in childhood epilepsy and ADHD remains mixed. Repetitive transcranial magnetic stimulation is emerging as a safe, tolerable, and potentially effective therapeutic strategy in a number of pediatric neurological disorders, though high-quality, randomized controlled trials are needed. Ongoing studies should focus on optimization of treatment protocols, development of biomarkers to identify children who will benefit from the technique, and identification of the most appropriate indicators of response.

Neuromodulation techniques for status epilepticus: A review

BACKGROUND

Electroconvulsive therapy (ECT), Vagal Nerve Stimulation (VNS), Transcranial Magnetic Stimulation (TMS) and Deep Brain Stimulation (DBS) are neuromodulation therapies that have been used to treat Status Epilepticus (SE).

OBJECTIVE

Review the literature about the efficacy and safety of neuromodulation therapies in SE in humans.

METHODS

We searched studies in PubMed, Scopus, Google Scholar and Science Direct (inception to June 2018). Four review authors independently selected the studies, extracted data and assessed the methodological quality of the studies using the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions, PRISMA guidelines, Oxford and GRADE scales, and Murad et al., 2018 methodological quality and synthesis of case series and case reports.

RESULTS

We analyzed 27 articles (45 patients) with 4 different neuromodulation therapies. In ECT we found 80% rate of disruption of SE and 5% of adverse events was reported. Using iVNS 15/16 (93.7%) patients resolved the SE. All patients who underwent TMS and DBS aborted SE, however, 50% of patients with DBS had severe adverse events.

CONCLUSIONS

Case series and case reports suggest that neuromodulation therapies can abort SE in 80-100% of patients (Oxford scale and GRADE were level 4 and D) with a wide range of adverse effects, which claims for prospective studies on the relationship be-tween efficacy and safety.

Proceedings of the 2016 annual meeting of the Fetal Alcohol Spectrum Disorders Study Group

The 2016 Fetal Alcohol Spectrum Disorders Study Group (FASDSG) meeting was titled "Rehabilitation in FASD: Potential Interventions and Challenges". During the previous decades, studies with human subjects and animal models have improved much of our understanding of the mechanisms underlying FASD, putting the scientific community in a good position to test hypotheses that can lead to potential therapeutic interventions. During the conference, two keynote speakers addressed potential interventions used in different fields and their applicability to FASD research. The conference also included updates from several government agencies, short presentations by junior and senior investigators that showcased the latest in FASD research, and award presentations. The conference was closed by a talk by Dr. Charles Goodlett, the recipient of the 2016 Henry Rosett award.

Oscillatory Activities in Neurological Disorders of Elderly: Biomarkers to Target for Neuromodulation

Non-invasive brain stimulation (NIBS) has been under investigation as adjunct treatment of various neurological disorders with variable success. One challenge is the limited knowledge on what would be effective neuronal targets for an intervention, combined with limited knowledge on the neuronal mechanisms of NIBS. Motivated on the one hand by recent evidence that oscillatory activities in neural systems play a role in orchestrating brain functions and dysfunctions, in particular those of neurological disorders specific of elderly patients, and on the other hand that NIBS techniques may be used to interact with these brain oscillations in a controlled way, we here explore the potential of modulating brain oscillations as an effective strategy for clinical NIBS interventions. We first review the evidence for abnormal oscillatory profiles to be associated with a range of neurological disorders of elderly (e.g., Parkinson's disease (PD), Alzheimer's disease (AD), stroke, epilepsy), and for these signals of abnormal network activity to normalize with treatment, and/or to be predictive of disease progression or recovery. We then ask the question to what extent existing NIBS protocols have been tailored to interact with these oscillations and possibly associated dysfunctions. Our review shows that, despite evidence for both reliable neurophysiological markers of specific oscillatory dis-functionalities in neurological disorders and NIBS protocols potentially able to interact with them, there are few applications of NIBS aiming to explore clinical outcomes of this interaction. Our review article aims to point out oscillatory markers of neurological, which are also suitable targets for modification by NIBS, in order to facilitate in future studies the matching of technical application to clinical targets.

The Hemiconvulsions-Hemiplegia-Epilepsy (HHE) syndrome: a transcranial magnetic stimulation-EEG study

BACKGROUND

The Hemiconvulsions-Hemiplegia-Epilepsy (HHE) syndrome is currently regarded as an extremely rare condition. The etiological and pathophysiological mechanisms underlying this medical rarity as well as the optimal therapeutic approaches remain poorly defined and understood. We present the clinical, radiological and electroencephalography (EEG) findings of a patient with the HHE syndrome and describe the response of the continuously present epileptiform abnormalities to transcranial magnetic stimulation (TMS).

CASE DESCRIPTION

A 33-year old male patient was referred to our department for investigation and management of intractable epilepsy. His seizures began at the age of three months when, during the course of a common febrile illness, he developed repetitive clonic seizures involving the left upper and lower limbs, followed by permanent left hemiplegia. After extensive investigations, he was diagnosed with "idiopathic" HHE syndrome. Currently, he suffers from left hemiplegia, severe intellectual impairment [Intelligence Quotient (IQ) <30] and asymmetric, bilateral tonic seizures occurring 1-3 times daily despite treatment with valproate, topiramate, lamotrigine, rufinamide, and perampanel. Brain magnetic resonance imaging revealed atrophy of the right hemisphere and serial EEGs disclosed continuous sharp waves, the generators of which were localized by electrical source imaging (ESI) to two distinct sources within the right hemisphere. Repetitive TMS [210 stimuli of 1 Hz at 100 % corticomotor threshold applied with a circular coil over the generators of epileptic discharges (EDs)] resulted in a statistically significant decrease of ED counts compared to sham stimulation and the post-verum TMS period.

CONCLUSION

We present the clinical-laboratory profile and the long-term follow up of a patient with the HHE syndrome. Further, we describe the effects of TMS on EDs. The latter observation raises the possibility that TMS-EEG may be used in select cases with intractable epilepsy as a surrogate marker of responsiveness to more invasive modalities (i.e., cortical stimulation). HIPPOKRATIA 2017, 21(2): 101-104.

Safety of Transcranial Magnetic Stimulation in Children: A Systematic Review of the Literature

BACKGROUND

Data and best practice recommendations for transcranial magnetic stimulation (TMS) use in adults are largely available. Although there are fewer data in pediatric populations and no published guidelines, its practice in children continues to grow.

METHODS

We performed a literature search through PubMed to review all TMS studies from 1985 to 2016 involving children and documented any adverse events. Crude risks were calculated per session.

RESULTS

Following data screening we identified 42 single-pulse and/or paired-pulse TMS studies involving 639 healthy children, 482 children with central nervous system disorders, and 84 children with epilepsy. Adverse events occurred at rates of 3.42%, 5.97%, and 4.55% respective to population and number of sessions. We also report 23 repetitive TMS studies involving 230 central nervous system and 24 children with epilepsy with adverse event rates of 3.78% and 0.0%, respectively. We finally identified three theta-burst stimulation studies involving 90 healthy children, 40 children with central nervous system disorder, and no epileptic children, with adverse event rates of 9.78% and 10.11%, respectively. Three seizures were found to have occurred in central nervous system disorder individuals during repetitive TMS, with a risk of 0.14% per session. There was no significant difference in frequency of adverse events by group (P = 0.988) or modality (P = 0.928).

CONCLUSIONS

Available data suggest that risk from TMS/theta-burst stimulation in children is similar to adults. We recommend that TMS users in this population follow the most recent adult safety guidelines until sufficient data are available for pediatric specific guidelines. We also encourage continued surveillance through surveys and assessments on a session basis.

Bursts of high-frequency repetitive transcranial magnetic stimulation (rTMS), together with lorazepam, suppress seizures in a rat kainate status epilepticus model

BACKGROUND

Status epilepticus (SE) is a condition of prolonged or recurrent and often drug-resistant seizures where nonsedating SE therapy remains an important unmet need. Repetitive transcranial magnetic stimulation (rTMS) is emerging as a means to suppress seizures but has not been extensively studied in models.

OBJECTIVES

We aimed to test the antiepileptic potential of high-frequency rTMS in SE. As a step toward eventual coupling of rTMS with antiepileptic pharmacotherapy, we also tested whether high-frequency rTMS in combination with a low (ineffective but less likely to cause a side effect) lorazepam dose is as effective as a full lorazepam dose in suppressing seizures in a rat SE model.

METHODS

EEG was recorded to measure epileptic spike frequency in the rat kainate SE model. Epileptic spikes were counted before, during, and after either high-frequency rTMS treatment alone or high-frequency rTMS treatment in combination with lorazepam, a firstline SE treatment.

RESULTS

We found that rTMS alone decreases epileptic spike frequency only acutely. However, combinatory treatment with half-dose lorazepam together with rTMS was as effective as a full lorazepam dose.

CONCLUSION

We report that high-frequency rTMS has modest antiepileptic potential alone but acts in complement with lorazepam to suppress seizures.

Safety of repetitive transcranial magnetic stimulation in patients with epilepsy: A systematic review

Approximately one-third of patients with epilepsy remain with pharmacologically intractable seizures. An emerging therapeutic modality for seizure suppression is repetitive transcranial magnetic stimulation (rTMS). Despite being considered a safe technique, rTMS carries the risk of inducing seizures, among other milder adverse events, and thus, its safety in the population with epilepsy should be continuously assessed. We performed an updated systematic review on the safety and tolerability of rTMS in patients with epilepsy, similar to a previous report published in 2007 (Bae EH, Schrader LM, Machii K, Alonso-Alonso M, Riviello JJ, Pascual-Leone A, Rotenberg A. Safety and tolerability of repetitive transcranial magnetic stimulation in patients with epilepsy: a review of the literature. Epilepsy Behav. 2007; 10 (4): 521-8), and estimated the risk of seizures and other adverse events during or shortly after rTMS application. We searched the literature for reports of rTMS being applied on patients with epilepsy, with no time or language restrictions, and obtained studies published from January 1990 to August 2015. A total of 46 publications were identified, of which 16 were new studies published after the previous safety review of 2007. We noted the total number of subjects with epilepsy undergoing rTMS, medication usage, incidence of adverse events, and rTMS protocol parameters: frequency, intensity, total number of stimuli, train duration, intertrain intervals, coil type, and stimulation site. Our main data analysis included separate calculations for crude per subject risk of seizure and other adverse events, as well as risk per 1000 stimuli. We also performed an exploratory, secondary analysis on the risk of seizure and other adverse events according to the type of coil used (figure-of-8 or circular), stimulation frequency (≤ 1 Hz or > 1 Hz), pulse intensity in terms of motor threshold (<100% or ≥ 100%), and number of stimuli per session (< 500 or ≥ 500). Presence or absence of adverse events was reported in 40 studies (n = 426 subjects). A total of 78 (18.3%) subjects reported adverse events, of which 85% were mild. Headache or dizziness was the most common one, occurring in 8.9%. We found a crude per subject seizure risk of 2.9% (95% CI: 1.3-4.5), given that 12 subjects reported seizures out of 410 subjects included in the analysis after data of patients with epilepsia partialis continua or status epilepticus were excluded from the estimate. Only one of the reported seizures was considered atypical in terms of the clinical characteristics of the patients' baseline seizures. The atypical seizure happened during high-frequency rTMS with maximum stimulator output for speech arrest, clinically arising from the region of stimulation. Although we estimated a larger crude per subject seizure risk compared with the previous safety review, the corresponding confidence intervals contained both risks. Furthermore, the exclusive case of atypical seizure was the same as reported in the previous report. We conclude that the risk of seizure induction in patients with epilepsy undergoing rTMS is small and that the risk of other adverse events is similar to that of rTMS applied to other conditions and to healthy subjects. Our results should be interpreted with caution, given the need for adjusted analysis controlling for potential confounders, such as baseline seizure frequency. The similarity between the safety profiles of rTMS applied to the population with epilepsy and to individuals without epilepsy supports further investigation of rTMS as a therapy for seizure suppression.

H-coil repetitive transcranial magnetic stimulation for treatment of temporal lobe epilepsy: A case report

Low frequency repetitive TMS (rTMS) of a cortical seizure focus is emerging as an antiepileptic treatment. While conventional rTMS stimulators activate only superficial cortical areas, reaching deep epileptic foci, for example in temporal lobe epilepsy (TLE), is possible using specially designed H-coils. We report the results of rTMS in a young adult with pharmacoresistant bilateral TLE who underwent three courses (of 10, 15, and 30 daily sessions) of unilateral rTMS over the hemisphere from which seizures originated most often. Seizure frequency was assessed before and after each block of rTMS sessions, as was the tolerability of the procedure. Seizure frequency declined significantly, by 50 to 70% following each rTMS course. All sessions were well-tolerated.

Transcranial Magnetic Stimulation for Status Epilepticus

Background. Our goal was to perform a systematic review on the use of repetitive transcranial magnetic stimulation (rTMS) in the treatment of status epilepticus (SE) and refractory status epilepticus (RSE). Methods. MEDLINE, BIOSIS, EMBASE, Global Health, Healthstar, Scopus, Cochrane Library, the International Clinical Trials Registry Platform, clinicaltrials.gov (inception to August 2015), and gray literature were searched. The strength of evidence was adjudicated using Oxford and GRADE methodology. Results. We identified 11 original articles. Twenty-one patients were described, with 13 adult and 8 pediatric. All studies were retrospective. Seizure reduction/control with rTMS occurred in 15 of the 21 patients (71.4%), with 5 (23.8%) and 10 (47.6%) displaying partial and complete responses, respectively. Seizures recurred after rTMS in 73.3% of the patients who had initially responded. All studies were an Oxford level 4, GRADE D level of evidence. Conclusions. Oxford level 4, GRADE D evidence exists to suggest a potential impact on seizure control with the use of rTMS for FSE and FRSE, though durability of the therapy is short-lived. Routine use of rTMS in this context cannot be recommended at this time. Further prospective study of this intervention is warranted.

Direct Causal Networks for the Study of Transcranial Magnetic Stimulation Effects on Focal Epileptiform Discharges

Background: Transcranial magnetic stimulation (TMS) can have inhibitory effects on epileptiform discharges (EDs) of patients with focal seizures. However, the brain connectivity before, during and after EDs, with or without the administration of TMS, has not been extensively explored. Objective: To investigate the brain network of effective connectivity during ED with and without TMS in patients with focal seizures. Methods: For the effective connectivity a direct causality measure is applied termed partial mutual information from mixed embedding (PMIME). TMS-EEG data from two patients with focal seizures were analyzed. Each EEG record contained a number of EDs in the majority of which TMS was administered over the epileptic focus. As a control condition, sham stimulation over the epileptogenic zone or real TMS at a distance from the epileptic focus was also performed. The change in brain connectivity structure was investigated from the causal networks formed at each sliding window. Conclusion: The PMIME could detect distinct changes in the network structure before, within, and after ED. The administration of real TMS over the epileptic focus, in contrast to sham stimulation, terminated the ED prematurely in a node-specific manner and regained the network structure as if it would have terminated spontaneously.

Transcranial magnetic stimulation: A potential new treatment for depression associated with traumatic brain injury

BACKGROUND

Each year, more than 1.7 million Americans suffer a traumatic brain injury (TBI) and the lifetime prevalence of major depressive disorder following TBI is between 25-50%. There are no validated established strategies to treat TBI depression. Repetitive transcranial magnetic stimulation (rTMS) is a novel putative treatment option for post-TBI depression, which, compared with standard pharmacological agents, may provide a more targeted treatment with fewer side-effects. However, TBI is associated with an increased risk of both early and late spontaneous seizures, a significant consideration in evaluating rTMS as a potential treatment for TBI depression. Whilst the risk of seizure from rTMS is low, underlying neuropathology may somewhat increase that risk.

REVIEW

This review focuses on the safety aspects of rTMS in TBI patients. The authors review why low frequency rTMS might be less likely to trigger a seizure than high frequency rTMS and propose low frequency rTMS as a safer option in TBI patients. Because there is little data on the safety of rTMS in TBI, the authors also review the safety of rTMS in patients with other brain pathology.

CONCLUSION

It is concluded that pilot safety and tolerability studies should be first conducted in persons with TBI and neuropsychiatric comorbidities. These results could be used to help design larger randomized controlled trials.

Feasibility of transcranial direct current stimulation use in children aged 5 to 12 years

Transcranial direct current stimulation is a noninvasive brain stimulation technique that has been studied for the treatment of neuropsychiatric disorders in adults, with minimal side effects. The objective of this study is to report the feasibility, tolerability, and the short-term adverse effects of transcranial direct current stimulation in children from 5 to 12 years of age. It is a naturalistic study of 14 children who underwent 10 sessions of transcranial direct current stimulation as an alternative, off-label, and open-label treatment for various languages disorders. Frequency, intensity, adverse effects, and perception of improvement reported by parents were collected. The main side effects detected were tingling (28.6%) and itching (28.6%), acute mood changes (42.9%), and irritability (35.7%). Transcranial direct current stimulation is a feasible and tolerable technique in children, although studies regarding plastic and cognitive changes in children are needed to confirm its safety. In conclusion, this is a naturalistic report in which we considered transcranial direct current stimulation as feasible in children.

Evidence-based guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS)

A group of European experts was commissioned to establish guidelines on the therapeutic use of repetitive transcranial magnetic stimulation (rTMS) from evidence published up until March 2014, regarding pain, movement disorders, stroke, amyotrophic lateral sclerosis, multiple sclerosis, epilepsy, consciousness disorders, tinnitus, depression, anxiety disorders, obsessive-compulsive disorder, schizophrenia, craving/addiction, and conversion. Despite unavoidable inhomogeneities, there is a sufficient body of evidence to accept with level A (definite efficacy) the analgesic effect of high-frequency (HF) rTMS of the primary motor cortex (M1) contralateral to the pain and the antidepressant effect of HF-rTMS of the left dorsolateral prefrontal cortex (DLPFC). A Level B recommendation (probable efficacy) is proposed for the antidepressant effect of low-frequency (LF) rTMS of the right DLPFC, HF-rTMS of the left DLPFC for the negative symptoms of schizophrenia, and LF-rTMS of contralesional M1 in chronic motor stroke. The effects of rTMS in a number of indications reach level C (possible efficacy), including LF-rTMS of the left temporoparietal cortex in tinnitus and auditory hallucinations. It remains to determine how to optimize rTMS protocols and techniques to give them relevance in routine clinical practice. In addition, professionals carrying out rTMS protocols should undergo rigorous training to ensure the quality of the technical realization, guarantee the proper care of patients, and maximize the chances of success. Under these conditions, the therapeutic use of rTMS should be able to develop in the coming years.

Suppression of motor cortical excitability in anesthetized rats by low frequency repetitive transcranial magnetic stimulation

Repetitive transcranial magnetic stimulation (rTMS) is a widely-used method for modulating cortical excitability in humans, by mechanisms thought to involve use-dependent synaptic plasticity. For example, when low frequency rTMS (LF rTMS) is applied over the motor cortex, in humans, it predictably leads to a suppression of the motor evoked potential (MEP), presumably reflecting long-term depression (LTD) -like mechanisms. Yet how closely such rTMS effects actually match LTD is unknown. We therefore sought to (1) reproduce cortico-spinal depression by LF rTMS in rats, (2) establish a reliable animal model for rTMS effects that may enable mechanistic studies, and (3) test whether LTD-like properties are evident in the rat LF rTMS setup. Lateralized MEPs were obtained from anesthetized Long-Evans rats. To test frequency-dependence of LF rTMS, rats underwent rTMS at one of three frequencies, 0.25, 0.5, or 1 Hz. We next tested the dependence of rTMS effects on N-methyl-D-aspartate glutamate receptor (NMDAR), by application of two NMDAR antagonists. We find that 1 Hz rTMS preferentially depresses unilateral MEP in rats, and that this LTD-like effect is blocked by NMDAR antagonists. These are the first electrophysiological data showing depression of cortical excitability following LF rTMS in rats, and the first to demonstrate dependence of this form of cortical plasticity on the NMDAR. We also note that our report is the first to show that the capacity for LTD-type cortical suppression by rTMS is present under barbiturate anesthesia, suggesting that future neuromodulatory rTMS applications under anesthesia may be considered.

Transcranial magnetic stimulation for refractory focal status epilepticus in the intensive care unit

PURPOSE

To examine the efficacy and safety profile of antiepileptic repetitive transcranial magnetic stimulation (rTMS) for refractory status epilepticus (RSE) in the intensive care unit (ICU) setting. In addition, hypothetical concerns about electrical interference of rTMS with ICU equipment have been previously raised.

METHODS

We describe two cases of RSE treated with rTMS in the ICU.

RESULTS

In one case, rTMS contributed to decreased seizure frequency; in the second case, rTMS transiently decreased seizure frequency. In both cases, rTMS was safe and did not interfere with the functioning of the ICU equipment.

CONCLUSION

rTMS is a potential therapy for RSE when conventional therapies have failed. Future studies should investigate the efficacy of various rTMS stimulation parameters, safety issues, and bioengineering considerations in the ICU setting.

The effects of responsive and scheduled subicular high frequency stimulation in the intra-hippocampal kainic acid seizure model

BACKGROUND

Responsive stimulation is a promising and newly emerging treatment for refractory temporal lobe epilepsy in which current is delivered to target areas following seizure occurrence.

OBJECTIVE

We compared responsive and scheduled subicular high frequency stimulation (HFS) with a sham control group on acute seizures and seizure sensitivity two weeks later. We also investigated the role of status epilepticus (SE) on efficacy of both types of stimulation.

METHOD

Adult Wistar rats received kainic acid (KA) injections intrahippocampally until they reached Stage V (Racine scale) on Day 1. Responsive, scheduled or sham HFS (125 Hz, 100 μs) was delivered in three groups while EEG was recorded. All rats received KA injections again on Day 15 to measure the excitability of animals to KA, again with EEG monitoring.

RESULTS

All rats reached Stage V and 60% reached SE on Day 1. Focal seizures were suppressed in both stimulated groups (the scheduled group was slightly more effective) on both days in only non-SE rats. Similar stimulation effects were found on generalized seizures but mainly on Day 15.

CONCLUSION

Both types of subicular HFS suppressed focal and generalized seizures, albeit differently. Scheduled stimulation seemed a bit more effective, and the amount of stimulation might be a factor that influences the differences between the stimulated groups. Beneficial effects of HFS were restricted to non-SE rats and HFS did not suppress or even worsen seizures in SE rats.

NON-INVASIVE BRAIN STIMULATION IN CHILDREN: APPLICATIONS AND FUTURE DIRECTIONS

Transcranial magnetic stimulation (TMS) is a neurostimulation and neuromodulation technique that has provided over two decades of data in focal, non-invasive brain stimulation based on the principles of electromagnetic induction. Its minimal risk, excellent tolerability and increasingly sophisticated ability to interrogate neurophysiology and plasticity make it an enviable technology for use in pediatric research with future extension into therapeutic trials. While adult trials show promise in using TMS as a novel, non-invasive, non-pharmacologic diagnostic and therapeutic tool in a variety of nervous system disorders, its use in children is only just emerging. TMS represents an exciting advancement to better understand and improve outcomes from disorders of the developing brain.

Epilepsy

Noninvasive brain stimulation, particularly transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), are emerging as realistic tools for seizure control. Numerous open-label trials and a few recent randomized controlled trials suggest the capacity of both techniques to suppress seizures. Additionally, specialized TMS protocols aimed to map cortical function and to measure cortical excitability may have realistic roles as diagnostic tools in epilepsy. As the prevalence of drug-resistant epilepsy has not changed in recent years, TMS and tDCS offer noninvasive and nonpharmacological options to improve control of intractable seizures.